Space Facts That Make You Want to Be an Astronaut

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Transcript

00:00:00In 2017, a strange object was spotted in our Solar System.

00:00:06It had the shape of a long tube, similar to a pancake.

00:00:10No known asteroid or comet we've seen looks like that.

00:00:13Its exterior was also peculiar.

00:00:16It was at least 10 times more reflective than the average stuff that flies through space,

00:00:20with some saying it had a surface similar to polished metal.

00:00:24When it went past the Sun and left our reach, it accelerated faster than what our gravity

00:00:29could account for.

00:00:31At first glance, it was like this thing had a rocket strapped to its back.

00:00:35This unusual visitor even got a special name – Amuamua.

00:00:39It comes from Hawaiian and translates to scout or visitor from a faraway land.

00:00:45And because of its characteristics, scientists soon began to wonder if this was, at last,

00:00:50a visit from otherworldly creatures.

00:00:55So they went full-on with the science fiction suppositions.

00:00:59Astronomers gathered the information they were sure about.

00:01:02Starting with the fact that Amuamua must've come from another solar system.

00:01:06There must've been some unfortunate event in its home system that led to its ejection.

00:01:11What they didn't know was that this was a comet or asteroid.

00:01:15They're both celestial objects orbiting the Sun, but they have distinct compositions

00:01:19and behaviors.

00:01:21Comets are composed primarily of ice, dust, and rocky material, often referred to as dirty

00:01:26snowballs.

00:01:28When a comet approaches the Sun, the heat causes the ice to vaporize, releasing gas

00:01:32and dust particles into space.

00:01:35This creates a bright glowing tail that can extend for millions of miles.

00:01:40Comets generally have elliptical orbits, often taking them from the distant reaches of our

00:01:44solar system closer to the Sun.

00:01:49Comets, however, are mostly made of rock and metal.

00:01:52In our neighborhood, they are remnants of the early formation of the solar system and

00:01:57are typically found in the asteroid belt between Mars and Jupiter.

00:02:01Unlike comets, asteroids do not develop tails when they approach the Sun, as they have no

00:02:06ice.

00:02:07Their orbits generally follow more circular paths compared to comets.

00:02:12By all accounts, Amuamua should be a comet because it seems to come from a different

00:02:17location in the universe.

00:02:20But it doesn't exhibit the typical signs of cometary activity.

00:02:24Amuamua lacks a tail and does not spew out gas as it passes by, not like me.

00:02:30Even though it behaves like a comet, it looks more like an asteroid.

00:02:36Another big question is how scientists even managed to spot Amuamua in the first place.

00:02:42Considering the vastness of space and time in the galaxy, it's remarkable.

00:02:46Stars have lifetimes spanning millions or billions of years.

00:02:50And the formation of a solar system takes hundreds of millions of years.

00:02:54Even the fastest objects take tens of thousands of years to travel from one star to another.

00:03:00In contrast, humans have only been observing the skies with telescopes for around 400 years,

00:03:06a tiny fraction of cosmic time.

00:03:09And it's only in recent decades, even years, that we've had the technology to detect

00:03:14and track fast-moving, dim objects.

00:03:17Either rocks like these are abundant, or we've been incredibly lucky with our detections.

00:03:22Or it simply wanted to be seen.

00:03:27Another question that was asked was where such objects could come from.

00:03:31It's highly unlikely that Amuamua came from a mature, stable solar system.

00:03:37That's because such systems don't eject enough material to fill up the galaxy.

00:03:41Occasionally, a random rock might get flung out, but it can rarely travel so far.

00:03:47Young systems, however, act differently.

00:03:50In these chaotic environments, collisions, mergers, and migrations are happening everywhere.

00:03:56Plenty of tiny rocks roam around, perfect candidates for ejection.

00:04:00The solar system that kicked Amuamua out must've had a planet similar to Jupiter.

00:04:06Its massive size and gravity could influence other objects in the system, causing potentially

00:04:11ejections.

00:04:12But not all solar systems develop Jupiter-sized planets.

00:04:16Often massive planets end up close to their stars, becoming hotter versions of Jupiter.

00:04:22These planets, snugly orbiting the Sun, are less likely to eject debris.

00:04:27Now Neptune-like planets may play a role too.

00:04:30While not as massive as Jupiter, they tend to call the outer regions of solar systems

00:04:34their home.

00:04:36Our solar system has the Kuiper Belt, a reservoir of comets in its outer reaches.

00:04:41During a solar system's early stages, interactions between Neptune-like planets and debris are

00:04:47common.

00:04:48Finding Neptune-like planets in other systems has been challenging though.

00:04:52Our methods for detecting exoplanets work better for massive objects close to their

00:04:56stars, making it difficult to spot Neptune counterparts farther out.

00:05:04Amuamua was also linked to a peculiar theory about how life came to be in the universe

00:05:09– panspermia.

00:05:11Now that's a hypothesis that suggests that life exists throughout the universe and can

00:05:16be distributed between planets by various means, such as asteroids, comets, or even

00:05:22spacecraft.

00:05:23It says that life must have originated in one location in the universe and then spread

00:05:28to other celestial bodies.

00:05:30Fans of the panspermia theory have suggested that such interstellar objects could potentially

00:05:35carry tiny microbes.

00:05:37Those building blocks of life between star systems.

00:05:41If such objects were to impact a planet or a moon, they could transfer these materials

00:05:46and seed the celestial body with life.

00:05:49For now, there is no evidence to support the theory that this comet in particular has transported

00:05:54life between star systems.

00:05:59After years of research, the overall consensus became that Amuamua was indeed a comet.

00:06:05The reason why it moved so strangely is because it might have frozen hydrogen on its surface

00:06:10that reacts when touched by sunlight.

00:06:13The closer it got to our Sun, the faster it became, releasing that hydrogen and also changing

00:06:18its path through our solar system.

00:06:21Its color also supports this theory – it's red, which might mean it's been hit by cosmic

00:06:26rays for a long time.

00:06:28The longer it was touched by those rays, the more hydrogen it gathered in the process.

00:06:34But since they can't be completely sure, astronomers have a plan to follow this visitor.

00:06:39One idea is to send a mission to check it out.

00:06:42It's already far away from us, but it may not be too late just yet.

00:06:47We may be able to send a probe fast enough to catch up with the comet.

00:06:51The plan was named Project Lyra, and aims to use the Earth's orbit and that of Jupiter

00:06:56to bounce out a probe far enough to reach Amuamua.

00:07:00If it works, it will be the fastest space device we've sent out in the Universe.

00:07:05One potential trajectory of the space probe involves the gravitational pull of our planet

00:07:10and that of Jupiter as a lasso effect, but not Ted Lasso.

00:07:15The probe will leave our planet and re-enter Earth's orbit before sending it to meet

00:07:19with Jupiter's pull.

00:07:20It will be sent back near our planet a second time, where it will be ejected with enough

00:07:25force to reach the comet.

00:07:30Project Lyra also aims to follow a second far-away visitor, named Borisov.

00:07:35This one was discovered by an amateur astronomer and now bears his name.

00:07:39What's interesting about it is that it's, well, spotless.

00:07:44Similar to our experience with Amuamua, we haven't seen anything like Borisov before

00:07:48either.

00:07:49Studies of the light coming from its cloud of dust and gas show it's very clean compared

00:07:54to other space objects.

00:07:56After it was first noticed in August 2019, astronomers studied its path through our solar

00:08:02system and concluded it came from another star too.

00:08:06But Borisov gave us more time to study it because we spotted it earlier in its journey

00:08:11through our neighborhood.

00:08:13Researchers used advanced telescopes to look at the dust coming off Borisov.

00:08:17They found it's throwing off over 400 pounds of dust every second.

00:08:22They also found Borisov has more carbon monoxide than comets from our solar system usually

00:08:27do.

00:08:28But the amount isn't the same everywhere on the comet.

00:08:31This tells us the space object probably started forming near its home star before moving away,

00:08:37maybe because of larger planets in its system.

00:08:40The light from Borisov is way more polarized than light from other comets we've seen,

00:08:45and its cloud is super smooth.

00:08:47This tells us Borisov has never interacted with another star.

00:08:57You know, back in the 1970s, scientists discovered a mysterious gravitational anomaly called

00:09:02the Great Attractor.

00:09:03Wait a minute, I had that nickname in high school!

00:09:07Anyway, it's a place in the sky that draws hundreds of galaxies, including our Milky

00:09:11Way.

00:09:12You won't be able to see it because it's on the other side of the Milky Way, 150 million

00:09:17light-years away.

00:09:19The Great Attractor actually lies in the direction scientists usually call the Zone of Avoidance.

00:09:25I have one of those too.

00:09:26It's my closet.

00:09:27Now, there's so much dust and gas in this region that we can't see what's happening

00:09:32there.

00:09:33That area blocks most of the visible light from beyond.

00:09:36But all that dust and gas don't block X-rays and infrared light.

00:09:41So as X-ray astronomy developed, researchers could finally start to observe all the objects

00:09:46within that area, including the mysterious force attracting everything.

00:09:51But so far, no one has figured out why it's happening.

00:09:55Our Moon may be 200 million years younger than we previously thought.

00:10:00Many scientists believe that the Moon formed during a powerful collision between our planet

00:10:04and an unknown Mars-sized body.

00:10:07The molten dust and debris got together and formed a new object we know as the Moon.

00:10:12The lunar crust was probably going through a process of solidifying over a couple of

00:10:17hundred million years.

00:10:19Did you know about an early magma ocean on the Moon?

00:10:22Scientists realized it was a real thing after they had discovered big amounts of the lightweight

00:10:27mineral called plagioclase.

00:10:29This material usually crystallizes and floats to the surface of magma.

00:10:33Anyway, this mineral was 4.36 billion years old, which means it formed 200 million years

00:10:39after the first solid materials had appeared in our solar system.

00:10:43Thus, the theory that the Moon formed during this giant chaotic collision might be true.

00:10:49If you stand on the Moon one day and leave your footprint on its surface, it can stay

00:10:53there for a million years.

00:10:55You'd also see the footprints of other astronauts, even though no one has landed on the lunar

00:11:00surface for decades now.

00:11:02The Moon doesn't have a full-fledged atmosphere.

00:11:05There's no breeze or anything else that can sweep up the dust and erase the footprints.

00:11:10We see it as a small dot somewhere in the distance.

00:11:13But in reality, the Sun is so big that if it were an empty ball, you could fill it with

00:11:18more than a million Earths.

00:11:20The Sun makes up 99.86% of the mass of our entire solar system.

00:11:26Another enormous object in our solar system is Jupiter.

00:11:29It's 11 times wider than our planet.

00:11:32For example, Earth isn't even the size of the Great Red Spot.

00:11:36This enormous storm has been raging on Jupiter for more than a century.

00:11:40And no, it's not anchored to anything solid since Jupiter is a gas giant.

00:11:45It's like a massive hurricane, oval in shape, reddish in color, and wide enough to engulf

00:11:51our home planet.

00:11:53Once upon a time, it was three times as wide as our planet.

00:11:56But over the last few centuries, it's been shrinking as well as growing taller.

00:12:01As for Jupiter, this gas giant is some sort of vacuum cleaner that keeps our solar system

00:12:06safe.

00:12:07Jupiter has incredibly strong gravity that eats up comets or asteroids that might potentially

00:12:12harm our home planet.

00:12:14In some other planetary systems, gas giants similar to Jupiter migrate from the position

00:12:20where they formed.

00:12:21They spiral inward and come closer to their parent stars.

00:12:25And as they travel, they swallow up small rocky planets.

00:12:29Or their strong gravitational force flings these planets out of their star systems.

00:12:34Luckily for us, Jupiter's gravitational force doesn't work that way.

00:12:38If Jupiter-like planets stay away from their stars, they keep their planetary systems safe,

00:12:43protecting those small planets in their inner orbit.

00:12:46Jupiter, for instance, can change the orbits of small space bodies that come too close

00:12:51to the inner planets of our solar system.

00:12:54That's why this gas giant is a good guardian of our solar system.

00:12:58Now there's a supermassive black hole that roams through space at a speed of 3 million

00:13:04miles per hour and leaves a trail of debris behind.

00:13:07Hey, I had a little brother who once did that.

00:13:10It's about a million times as heavy as our Sun and, at the moment, 2 billion light-years

00:13:15away from Earth.

00:13:16This black hole started like any other – in its own elliptical galaxy with many stars

00:13:21surrounding it.

00:13:23Supermassive black holes often form and remain in the center of galaxies.

00:13:27This one got away.

00:13:29One theory claims that this black hole is different because the galaxy where it formed

00:13:33may have bumped into another galaxy at one point in the past.

00:13:37Sometimes galaxies merge into a new one if this happens.

00:13:41But not this time.

00:13:43Instead of merging, the black hole's galaxy passed through a way bigger one millions of

00:13:47years ago.

00:13:49That giant galaxy already swallowed up some other galaxies along the way.

00:13:53But since it was so large, the galaxy surrounding our supermassive black hole ended up ripped

00:13:59apart.

00:14:00The black hole at its center managed to run away with some of the nearby stars.

00:14:04That's what left a burning trail stretching across the surrounding space.

00:14:10Solar superstorms are so powerful that they can cause blackouts all over the world.

00:14:15Random flares coming from the Sun cause solar storms, and they can really happen at any

00:14:20time.

00:14:21Back in 2012, we were lucky because the strongest solar storm in over 150 years passed very

00:14:28close to us.

00:14:29It just tore through Earth's orbit.

00:14:31If it had happened only a week earlier, our planet would've had to deal with tons of

00:14:35terrible consequences, including power outages all over the globe.

00:14:40Gamma-ray bursts are strong enough to destroy planets.

00:14:43We're talking about extremely strong bursts that mostly occur in galaxies very, very far

00:14:48away.

00:14:49If these rays are pointed directly at some space object, they can completely wreck it,

00:14:54even if we're talking about an entire planet.

00:14:57So Earth is safe for now, and we have nothing to be afraid of.

00:15:01A gamma-ray burst happens in our galaxy approximately once every 5 million years.

00:15:06Luckily, it occurs too far away and doesn't affect life on Earth.

00:15:11That's what I call irrelevant but still scary!

00:15:14A burning ice is a thing.

00:15:16It may be hard to picture it here on Earth, but one strange planet called Gliese 436 b

00:15:22is literally a burning ball of ice.

00:15:25It's covered with ice, but at the same time, it has temperatures of 822 degrees Fahrenheit.

00:15:31You can't actually see the planet burn since there's too much water on the planet.

00:15:35It's because of the strong gravitational force that pulls the water molecules to the core

00:15:40of the planet and packs them together incredibly densely.

00:15:43That way, water molecules can't evaporate, which is why the ice on the planet's surface

00:15:48doesn't melt.

00:15:50There are stars that can munch on other stars.

00:15:53These space objects are mostly smaller stars with a lower mass.

00:15:57They target the closest stars and begin to absorb their hydrogen fuel to boost their

00:16:01own mass and generally live longer.

00:16:04A vampire star becomes strikingly blue.

00:16:08It also gets hotter.

00:16:09This way, it seems that it's way younger than it actually is.

00:16:13If a star, or basically any other object, falls into a black hole, it gets stretched

00:16:19like spaghetti.

00:16:20This process is even called spaghettification.

00:16:23Dust storms on Mars can really go crazy.

00:16:25They hurtle through the Red Planet's southern hemisphere, especially during the summer.

00:16:30These storms can grow and encompass large areas of the planet, as happened in January

00:16:352022.

00:16:36Then, a dust storm covered almost twice the area of the United States.

00:16:41Could it be something like this that caused one of the robots we sent to Mars to go missing?

00:16:46The atmosphere and climate are harsh on Mars.

00:16:49It's mostly a desert with strong winds and average temperatures of minus 81 degrees Fahrenheit.

00:16:55It drops down to minus 220 at the poles during the winter.

00:16:59A lander needs to be specifically equipped and very sturdy to withstand such conditions.

00:17:04But researchers thought the Beagle 2 could handle the difficult trip to the Red Planet.

00:17:09June 3, 2003.

00:17:11A team of researchers got one of their pioneering robots they were about to send to space ready.

00:17:17It was a small and compact lander called the Beagle 2.

00:17:20Its mission was to touch down on Mars and search for what the world has been actively

00:17:25looking for for decades now – life on the Red Planet.

00:17:29The touchdown was due on December 25, but the signal never came.

00:17:34The team tried to contact the spaceship, but at one point, they had to accept they wouldn't

00:17:39be able to reach it.

00:17:41Some thought the landing was too difficult and complex after all, so the lander crashed.

00:17:46But they couldn't find any technical errors.

00:17:49Others had a theory that the lander may have become entangled in its own parachute and

00:17:53fell down to the surface of Mars.

00:17:55Either way, the Beagle 2 was considered missing.

00:17:59Until 2015, when NASA took pictures of what could be the remains of the lost lander.

00:18:05They weren't just smashed debris, the components actually looked to be intact.

00:18:09The lander's remains were lying with its solar panels partially deployed around 3 miles

00:18:14away from the site where it was supposed to land.

00:18:17Apparently, the Beagle 2 managed to land successfully, but its radio antenna got blocked.

00:18:24That's why researchers couldn't control it from Earth or communicate with it.

00:18:28But no one knows exactly why it happened.

00:18:31Have you heard of a face on Mars?

00:18:33In the 1970s, one of NASA's spaceships took the iconic images of the Martian surface that

00:18:39showed a face-like formation, as you can see in the upper part of the picture.

00:18:44If you have a rich imagination, you can easily see a nose, two eyes, a mouth, and an unusual

00:18:51hairdo.

00:18:52Some even thought it was a monument built on the Red Planet by another civilization.

00:18:57How about some other unusual things people have found on Mars, like Happy Face Crater?

00:19:03You can easily see why it has this nickname.

00:19:05Or rocks in different shapes – a pancake, brachiosaurus, or a fish.

00:19:11Mars also has a waffle-shaped island on its surface.

00:19:14It's a 1.2-mile-wide feature you can see in the area of lava flows.

00:19:19It might be the result of lava pushing this formation from below.

00:19:23It seems astronomers have also got some images of blue dunes.

00:19:27It's a sea of stunning dark dunes that strong winds sculpted into long lines.

00:19:33They surround the planet's northern polar cap and cover a region as large as Texas.

00:19:37The Red Planet is usually known for its brown, sandy dunes, so these ones certainly came

00:19:43as a surprise.

00:19:44In reality, though, they're not really blue.

00:19:47If you could visit Mars right now just to take a look, you'd see that these dunes appear

00:19:52brown and orange like the rest.

00:19:54And the picture is a false color image.

00:19:57Astronomers often use false colors to highlight differences in something.

00:20:00For example, here, it's the difference in depth.

00:20:04Also, the biggest valley on Mars is so large it could eat our Grand Canyon for breakfast.

00:20:10It's a fascinating system of canyons 2,500 miles long called Valles Marineris.

00:20:17And it's over 10 times as long as the Grand Canyon.

00:20:20Now, if you could stretch this Martian canyon, it would go from coast to coast of the entire

00:20:26United States.

00:20:27Since Mars doesn't have any active plate tectonics, no one knows for sure how this

00:20:32canyon formed.

00:20:34One theory says a chain of volcanoes located on the other side of Mars, the one that includes

00:20:39Olympus Mons, bent the crust from the opposite side of the planet.

00:20:44This powerful force caused cracks in the Martian crust as well as activated enormous amounts

00:20:49of water lying under the surface.

00:20:51This water then emerged and carved the rock away.

00:20:55The force activated glaciers too, and they possibly created new pathways in this gigantic

00:21:00canyon system.

00:21:03Volcanoes on the Martian surface could have erupted about 50,000 years ago, although the

00:21:07most powerful eruptions happened 2-3 billion years ago.

00:21:11But the planet doesn't have active volcanoes today.

00:21:15Most of the heat stored in its interior during the planet's formation has been lost.

00:21:20So now, Mars' outer crust is way too thick for the molten rock to reach the surface.

00:21:25But, a long time ago, eruptions formed giant volcanoes, and these volcanoes most likely

00:21:32had an important role in melting ice deposits, which released floods of water onto the Martian

00:21:37surface.

00:21:38Now, Mars has a thin atmosphere with a volume of gas, mostly carbon dioxide, less than 1%

00:21:45of Earth's.

00:21:464 billion years ago, it was way warmer and wetter than now.

00:21:50Its atmosphere must have been thicker back then too.

00:21:53That's why it could create a powerful greenhouse effect and trap sunlight.

00:21:58Mars also has a powerful magnetic field.

00:22:01Similar to Earth's, it formed because of the currents of molten metals in the planet's

00:22:05core.

00:22:06But unlike our home planet, Mars lost its magnetic field after its core had cooled down.

00:22:12And without it, the planet didn't have any protection from the solar wind, which

00:22:16is a stream of charged particles flowing from the Sun.

00:22:20The solar wind pulled away most of Mars' atmosphere in just a couple hundred million

00:22:24years, give or take.

00:22:26This is what makes those powerful Martian dust storms even more intense.

00:22:31Mars has a fascinating history.

00:22:32Judging by the planet's glaciers, Mars has probably gone through multiple ice ages, just

00:22:37like Earth.

00:22:38A team of researchers got images of about 60,000 Martian rocks.

00:22:43Rocks were different in size and distributed randomly, which means they probably formed

00:22:48during different ice ages.

00:22:50Glaciers hide their own stories too.

00:22:52Who knows what kinds of gases, rocks, or even microbes could be trapped inside?

00:22:57Now, if you could get into a time machine and stop it 4 billion years ago, on Mars of

00:23:02course, the chances are you'd see spectacular scenes of flooding.

00:23:07Maybe there would even be some form of life on the planet's surface.

00:23:11A strong meteorite impact that formed the Red Planet's Gale Crater could be something

00:23:16that triggered that mega-flood.

00:23:18After that collision, the temperatures on the planet got insanely hot.

00:23:22This caused the melting of all that ice that was stored on the Martian surface at that

00:23:26time.

00:23:27The flooding was so massive, it changed the geological structure of the planet's surface.

00:23:33It carved out big ripples as well as waves in the sedimentary rock.

00:23:37Now speaking of water, vapor has been noticed escaping the atmosphere of Mars.

00:23:42Also, researchers have found some evidence of water flowing on the planet's surface.

00:23:47There are dark streaks in the soil.

00:23:49They seem to get bigger in the summer and shrink over the winter.

00:23:53There are numerous dried-out valleys and river channels on the planet.

00:23:57It's possible that liquid water once flowed there.

00:24:00Now most of it could be locked up in ice caps or even hidden under the surface.

00:24:05When you look at photos taken from spaceships or the International Space Station that show

00:24:10sunlit objects like Earth or the Moon, something seems wrong.

00:24:14Space looks too empty.

00:24:17No magical scenery of a nighttime sky full of stars.

00:24:20It would be incredibly boring to go stargazing in space since the sky is always dark.

00:24:27During the daytime, the sky on our home planet is blue because of the diffusion of light.

00:24:32It happens when sunlight goes through the atmosphere.

00:24:35But if you were on the Moon or somewhere else in space, there would be no atmosphere

00:24:38to spread this light around.

00:24:40That's why the sky there would always appear black.

00:24:45But it doesn't mean less bright out there.

00:24:47If you were looking out the window of the space station, you'd see just as much direct

00:24:51sunlight as you would gazing out of your apartment window during a cloudless day.

00:24:56Maybe even more.

00:24:58When taking a picture on a sunny day, you'll probably use a short exposure, together with

00:25:02a narrow aperture setting on your camera.

00:25:05This way, just a short burst of light will get in.

00:25:08That's similar to how our pupils contract in sunlight so that they don't have to deal

00:25:12with too much light.

00:25:14And since it's just as bright up there in space, the process is the same when you take

00:25:18pictures of sunlit objects there.

00:25:21Using short exposure, you can get good, bright pictures of Earth or the surface of the Moon.

00:25:26But it also means there will be no stars in the picture.

00:25:29Even up there, stars are relatively dim.

00:25:32They don't emit enough light to show up in photos taken with such settings.

00:25:37Our home planet has a blue sky that slowly transforms into a beautiful orange-red palette

00:25:42at dusk and dawn.

00:25:44But if you ever get a chance to watch a sunset on Mars, you should expect the opposite, an

00:25:49orange-brown daytime sky that gets a bluish tint at sunset.

00:25:54First of all, Mars is farther away from the Sun than our planet.

00:25:58So when you're looking at the Sun from the Martian surface, of course, it looks fainter

00:26:02and smaller.

00:26:03And not just that.

00:26:04The Sun observed from Mars is just a bluish-white dot surrounded by a blue halo.

00:26:10The thin atmosphere of the red planet contains large dust particles.

00:26:14They create an effect called Mie scattering.

00:26:16It occurs when the diameter of particles in the atmosphere is almost the same as the wavelength

00:26:21of the scattered light.

00:26:22This effect filters out the red light from the Sun's rays.

00:26:26So only the blue light would reach your eyes on Mars.

00:26:31How come Earth doesn't have rings?

00:26:34All gas giants in our solar system, Jupiter, Saturn, Uranus, and Neptune have such rings,

00:26:40whereas the rocky planets Mercury, Venus, Earth, and Mars don't.

00:26:45There are two theories about how rings can appear around a planet.

00:26:48They might be just some material left from the times when the planet was forming.

00:26:53Or they may be the remains of a moon that got destroyed by a collision with some space

00:26:57body or torn apart by the strong gravitational pull of its parent planet.

00:27:02The gas giants formed in the outer regions of our solar system, while all the rocky planets

00:27:06are in the inner part.

00:27:08So maybe the inner planets were more protected from potential collisions that could have

00:27:12formed their rings.

00:27:14There are also more moons in the outer regions of our solar system, which could be another

00:27:19reason why the planets there have rings.

00:27:22Also, bigger planets have stronger gravity.

00:27:25It means that they can keep their rings stable after they form.

00:27:29Some experts believe Earth used to have a ring system a long time ago.

00:27:33A Mars-sized object might have collided with our home planet, which probably created a

00:27:37dense ring of debris around it.

00:27:41Some scientists think that this debris formed not a ring but what we know today as the moon.

00:27:47There's probably a giant planet lurking at the edge of the solar system, far beyond Neptune.

00:27:54Scientists call this mysterious hypothetical world Planet 9.

00:27:58If it does exist, it's probably similar to Uranus or Neptune, and 10 times more massive

00:28:03than our home planet.

00:28:05It's likely to circle around the Sun, but in the outer reaches of the solar system,

00:28:09about 20 times farther than Neptune.

00:28:12Another interesting theory says that Planet 9 could actually be a black hole the size

00:28:17of a grapefruit that warps space in a similar way a large planet would.

00:28:24Even though we once thought it was a rare substance in space, water exists all over

00:28:28our solar system.

00:28:30For example, you can often find it in asteroids and comets.

00:28:34It's also in craters on the Moon and Mercury.

00:28:37We still don't know if there's enough water to support potential human colonies if we

00:28:41decide to move there, but some amount of water is definitely present there.

00:28:47Mars has water at its poles, too.

00:28:49It's mostly hidden in the layers of ice and probably under the planet's dusty surface.

00:28:54Europa, Jupiter's moon, has some water, too.

00:28:58This is the most likely candidate we know about to host life outside Earth.

00:29:02There's probably a whole ocean of liquid water under its frozen surface.

00:29:07It might actually contain twice as much water as all of Earth's oceans combined.

00:29:13Neptune is unexpectedly warm.

00:29:16Even though it's 30 times as far from the Sun as our planet and receives less sunlight

00:29:19and heat, but it still radiates way more heat than it gets, it also has way more activity

00:29:26in its atmosphere than you'd suspect, especially if you compare it to its neighbor, Uranus.

00:29:32Both of these planets emit the same amount of heat, even though Uranus is much closer

00:29:37to the Sun.

00:29:38No one knows why.

00:29:40Neptune has extremely strong winds that can reach a speed of up to 1,500 miles per hour.

00:29:46Can they produce this heat?

00:29:47Or maybe it's because of the planet's core or its gravitational force?

00:29:53There's a monster black hole hurtling through space at a speed of 5 million miles per hour.

00:29:59Scientists located it with the Hubble Space Telescope.

00:30:02They believe it weighs as much as a billion suns.

00:30:05It was supposed to stay put in the center of its home galaxy, but some gravitational

00:30:09forces are pushing it around.

00:30:12At one point, this black hole is going to break free from its galaxy and continue roaming

00:30:16the universe.

00:30:17Luckily, it's still 8 billion years away from us.

00:30:22Solar storms are so powerful that they could leave us in complete darkness.

00:30:26Back in July 2012, the strongest solar storm in over 150 years narrowly missed Earth.

00:30:34Electrical mass ejections, or CMEs, are large bubbles of ionized gas.

00:30:40They tore through our orbit back then.

00:30:42If they had caught our planet in the crosshairs, we would have literally been in the firing

00:30:47line.

00:30:48We'd have faced solar matter hurtling towards Earth, damaging computers and causing power

00:30:52outages that would have lasted for months.

00:30:56A surprise solar storm hit us on June 25, 2022.

00:31:00One photographer even managed to capture stunning bright auroras that flashed across the dawn

00:31:04sky in Calgary, Canada, and lasted for 5 minutes.

00:31:08They were caused by the storm.

00:31:12Vampire stars are a real thing.

00:31:14They're part of a binary star, and they can literally drain the life out of the other

00:31:18star in the system.

00:31:20In space, no one can hear you scream.

00:31:23Or is that, in space, no one can hear ice cream?

00:31:26Well, either way, we know that no supernovas, crashing asteroids, and burning planets make

00:31:32a sound in space.

00:31:34Or do they?

00:31:36What if you actually can hear something out there?

00:31:38Well, let's see.

00:31:40Okie dokie, back to middle school.

00:31:43Sound is a mechanical wave originating from vibration.

00:31:47What exactly does that mean?

00:31:49The simplest example is guitar strings.

00:31:51Let's pluck one of them.

00:31:53It starts to vibrate.

00:31:54The atoms inside the metal string begin to push and beat the atoms of the air around

00:31:59them.

00:32:00Now atoms are constantly pushing each other until they reach our ears.

00:32:04It's like a wave from a pebble thrown into a pond, and it happens very quickly, at a

00:32:09speed of about 761 miles per hour.

00:32:13Then our eardrums begin to vibrate at the same frequency, and the little bones inside

00:32:18our ears transmit this vibration to the brain.

00:32:22The brain then does its magic, recognizes the pattern, and turns it into sounds.

00:32:28Great!

00:32:30Now we know that we need some particles to create sound.

00:32:33And we can find these particles in gases, liquids, and solid substances.

00:32:38And what about space?

00:32:39Nope, it's almost a perfect vacuum.

00:32:42And you've probably already heard that there's no sound in space because it's a vacuum.

00:32:47But what does it actually mean?

00:32:50Well, a vacuum is a perfect void.

00:32:53It's an area completely devoid of matter.

00:32:56It means there's nothing there.

00:32:58Yeah.

00:32:59Except for all those celestial bodies in space, there's actually no air in between them.

00:33:03No atoms, no particles, nothing.

00:33:06Nada.

00:33:07Zippo.

00:33:08Well, almost.

00:33:09To be honest, the perfect vacuum doesn't really exist.

00:33:12We can't get rid of atoms for good.

00:33:15But space is very close to this notion.

00:33:17On average, there are 15 to 80 atoms per one cubic inch.

00:33:22This may sound like a big number, but keep in mind that these atoms are tiny, and the

00:33:27void distance between them is huge.

00:33:30For comparison, one cubic inch of air contains about 16,000 atoms.

00:33:35So of course, with such a low density, these atoms can't push each other.

00:33:40Even if the vibration is very strong, like, I don't know, a supernova, they still won't

00:33:44be able to do that.

00:33:47So movies have been lying to us.

00:33:50All these epic space scenes actually take place in an awkward silence.

00:33:54Who would've guessed?

00:33:57But don't get upset.

00:33:59What if I tell you there are, in fact, some ways to hear sound in space?

00:34:05First of all, there's still sound on other planets.

00:34:08If there's an atmosphere on a space body, or at least something like gas, water, or

00:34:12a solid surface, there will be sound.

00:34:16In our case, the atmosphere becomes completely silent at about 60 miles above the Earth's

00:34:22surface.

00:34:23That's where the sky stops being blue and a black starry veil begins.

00:34:28In any case, we'd have to land on another planet, or at least get close to its atmosphere

00:34:33to hear something.

00:34:35But whatever it is, it would sound very different.

00:34:38Let's take our favorite Venus as an example.

00:34:42The atmosphere there is very dense.

00:34:44Scientists jokingly call it a thick chemical soup.

00:34:47No thanks.

00:34:49So if you somehow manage to stay alive and speak there, your voice would be very different.

00:34:55It would become much louder, and it would sound deeper.

00:35:00So if you want a pleasant baritone, you know what to do.

00:35:05I wonder what would happen if Earth had a denser atmosphere.

00:35:08What would we hear then?

00:35:10Well, you can vaguely imagine that if you've ever been in the water.

00:35:15Water is very dense.

00:35:16Sound moves there much faster and better compared to the air, at a speed of almost a mile per

00:35:22second, depending on the water temperature.

00:35:25So if you sit in an empty room with no sound sources, you won't hear much, right?

00:35:31Now dip your head in the water and check out how the same silence sounds here.

00:35:36It's not quiet at all.

00:35:37Even if you ignore the ever-present sounds of the water itself, you'll immediately notice

00:35:42how well you can hear your own body, how your blood pulsates in the veins, how your heart

00:35:47works, the slightest movement of your fingers.

00:35:50Kind of creepy, isn't it?

00:35:53This gives us an idea of what would happen to us on a planet with a denser atmosphere.

00:35:57And that's just crazy.

00:35:58We would hear everything.

00:36:01From scurrying animals to the movement of tectonic plates.

00:36:04Ah, come on, you'd probably say.

00:36:07It's obvious that there's sound on other planets.

00:36:10But didn't you say we can hear something in open space?

00:36:13Actually yes.

00:36:14For example, in a cloud of dust.

00:36:17You can find space dust almost everywhere in space.

00:36:20It may be the remains of a star or something else.

00:36:23And in these places, everything is a bit denser than usual.

00:36:27This means there are probably dust clouds where particles are very close to each other,

00:36:32which means they can produce sounds.

00:36:34Of course, those will be very quiet and transmitted over a very short distance.

00:36:40But it's better than nothing, right?

00:36:43Plus, we already have one real space sound recorded.

00:36:48It came from the Perseus galaxy, which is located 250 million light-years away from

00:36:52us.

00:36:54NASA recorded it in 2003.

00:36:57Those of us music geeks will want to know that it's a B-flat, 57 octaves below middle

00:37:03C on the piano.

00:37:04You'd have to add another 660 keys to the left on the keyboard.

00:37:09But its frequency is so low that the human ear, unfortunately, can't hear it.

00:37:14But besides that, we can only hear something inside spaceships.

00:37:18These are small pockets of air, after all.

00:37:22In a spacesuit, you would hear sounds very well too, including your breathing or blood

00:37:27circulation in a spacesuit.

00:37:29But two astronauts, flying side by side, wouldn't hear each other, even if they got

00:37:34very close and shouted very loudly.

00:37:36It's quite funny.

00:37:38If you, being an astronaut, bumped into something, it would be very loud for you, but your friend

00:37:43wouldn't hear anything.

00:37:44That's why astronauts use radio devices.

00:37:51Now purely theoretically, if you could somehow crawl out of your spacesuit and survive, you'd

00:37:57be able to hear the chatter and noises going on inside the spaceship.

00:38:01But how?

00:38:02So, look, we have some air inside the spaceship, and it transmits sound.

00:38:07It reaches the metal casing and gets through it.

00:38:10And then, if you leaned against the ship, preferably touching it with your elbow or

00:38:15knee, the sound would be transmitted to the brain directly through your bones, ignoring

00:38:20the ears.

00:38:21Yes, our bones conduct sound.

00:38:24That's how, for example, deaf people listen to music.

00:38:27It's called bone conduction.

00:38:29It's used in some headphones and some other technologies.

00:38:33You can do a little experiment.

00:38:35Hold your fingers over your ears.

00:38:37Shut them properly so that you really don't hear much.

00:38:40Then try to touch a sound source.

00:38:42It can be anything vibrating.

00:38:44For example, a speaker playing music with some part of your body where the bone is close

00:38:49to the skin.

00:38:50Now watch the miracle happen.

00:38:52You can hear the sound not through your ears, but directly in your brain.

00:38:57But please, don't repeat this experiment in open space.

00:39:00You know, ice cream?

00:39:02Now, you've probably heard about things like the sounds of space, where you can listen,

00:39:08for example, to the sounds made by the Sun or different planets.

00:39:12How do we record these ones?

00:39:14Easily.

00:39:15There is another way to hear sound in space – electromagnetic waves.

00:39:20You're sitting at a coffee shop on Mars, keeping your head down, trying not to draw any attention

00:39:24to yourself.

00:39:26It's crowded, and many people are singing, dancing, and talking loudly about life on

00:39:30Mars.

00:39:31Your drink arrives, and you sip on it.

00:39:33So far, no one recognizes you.

00:39:36You're wearing a cloak with a large hoodie to cover your face and disguise yourself from

00:39:40everyone.

00:39:41Someone accidentally bumps into you and sees your face.

00:39:45The music stops, and now everyone is staring at you.

00:39:48You have nowhere to hide or run.

00:39:50You ignore the leering eyes and keep sipping on your beverage.

00:39:54An old bearded man sits in front of you, amazed to be in your presence.

00:39:59So it's true.

00:40:01No one believed you'd make it, he says.

00:40:04You don't reply and continue with your drink.

00:40:07Everyone else gathers around you.

00:40:09Another man speaks.

00:40:10Well, are you not going to tell us how you escaped from the clutches of the Space Kraken?

00:40:17Everyone gasps in shock.

00:40:19No one has ever made it to tell the tale of the Kraken, except you.

00:40:24Your plan was to find your messenger to take you to a spaceship far away from this planet.

00:40:29But it's too late, now that everyone knows you're here.

00:40:32And the messenger fled, knowing all the attention was on you.

00:40:36You lay back your hoodie and explain what happened.

00:40:41Two days ago.

00:40:43You're in your full gear, ready to make the voyage into deep space.

00:40:48You have a solo ship that's designed to maneuver through all the obstacles in space.

00:40:51You prepare the rest of the gear and fuel up.

00:40:55Everyone is watching you, knowing that you might not make it back.

00:40:58But the Kraken has been floating in space for too long, disrupting shipping containers

00:41:03bringing in goods.

00:41:05A small ship like yours can sneak past its acute sense of smell and vision.

00:41:10But larger ships will get destroyed.

00:41:12You made it your mission to find this Kraken and study it.

00:41:16If you learn its ways and patterns, you can figure out how to get rid of it.

00:41:22Everyone says their goodbyes, and you lift off.

00:41:25You know that it'll be a very long way to get there, possibly three days in the emptiness

00:41:30of space.

00:41:31You saw some quick footage of it, but no one knows exactly where it sleeps, or if it even

00:41:37does sleep.

00:41:39You put on some tunes and set your ship for cruise control.

00:41:43You make some notes and set the camera to document yourself while you prepare everything

00:41:47you need.

00:41:48You also have some cameras outside recording everything that moves, even thermal sensors

00:41:54to catch living creatures floating in space.

00:41:57After a few hours, you exit the safe quarters of Mars and enter into the hostile territory.

00:42:04There is no place to hide or anyone to help you.

00:42:07A few little ships like yours pass by now and then.

00:42:10They watch you going further to the Kraken.

00:42:13You notice many floating signs powered by machines warning you about the Kraken.

00:42:18The cameras start recording, and you begin your video journal which is transmitting to

00:42:22your network at home.

00:42:24So far, nothing.

00:42:26It's quiet and dark.

00:42:28Hours pass, and you're just floating in the middle of nowhere.

00:42:31You almost feel like you want to turn around, but then you pick up something in the sensors.

00:42:37You see a large live object nearby.

00:42:39You turn off the lights and slow down your ship.

00:42:43You resume recording and start talking to yourself, explaining everything.

00:42:48The object is getting closer and closer.

00:42:51You move aside to avoid it and latch on to a floating rock, but you still don't see anything.

00:42:57Out of nowhere, you see some glowing jellyfish-like creatures flowing together in a cluster.

00:43:03On your thermal sensors, they appear to be large objects, but in fact, they are just

00:43:08little creatures.

00:43:09According to your studies, these creatures are some of the main foods for the Kraken,

00:43:14so they're probably running away from it.

00:43:17After a few minutes, the creatures float away, and you launch yourself out and turn the lights

00:43:22back on.

00:43:24A few more hours pass, and you still see no Kraken.

00:43:28Suddenly, a whoosh shakes your ship, and you're thrown slightly off course.

00:43:33You notice that a large object has spiked your thermal sensors and left.

00:43:38You keep going and check the playback settings to see if your cameras manage to catch something.

00:43:43You try to look carefully, but it seems like a gust of wind blew past you, which is weird

00:43:48because there is no wind in space.

00:43:51You check the thermal sensors and notice that a large object shaped like the Kraken has

00:43:56zipped past you.

00:43:58It's still around, and it has probably caught your scent.

00:44:01Your system's got some DNA particles and are studying them.

00:44:05After a while, they show that the Kraken's skin can change colors according to its surrounding.

00:44:11Its skin is thick and made up of some cosmic fluorescent material that is new to any creature

00:44:16you've ever come across.

00:44:19The system continues studying it.

00:44:21After a while, the Kraken goes off your radar and disappears.

00:44:25You circle back, trying to find it.

00:44:28People back on Mars can see the data and already have information about its size and skin quality.

00:44:34They even see some footage you've managed to catch.

00:44:37As you continue driving towards it, you open your floodlights, trying to see anything.

00:44:42Your cameras are still rolling.

00:44:44Suddenly, the Kraken changes skin color and appears right in front of you.

00:44:50Its large tentacles flash around, whipping nearby space debris.

00:44:54Its large eye that's as big as a bus looks right at you.

00:44:58It opens its mouth, and you see layers of sharp teeth circling like a grinder.

00:45:04It has a large beak that can break your ship easily.

00:45:08It starts flashing its colors rapidly as a way to warn you.

00:45:11It shoots out some liquid to move in a no-gravity space environment.

00:45:16It's moving towards you until it launches itself.

00:45:19Your ship has an auto-force field for protection, but it can't sustain the powerful bite of

00:45:23the Kraken.

00:45:25After only a few seconds, the shield breaks, and your ship spirals down to another planet.

00:45:31You crash-landed in a swampy land.

00:45:33Your ship has survived, but it can't take off.

00:45:37The analysis of the Kraken is ready.

00:45:39It shows that it doesn't need oxygen to breathe, and its DNA is evolving.

00:45:45Now that it got a bite of your force field, it can adapt itself to create a bio-force

00:45:50field of a similar nature.

00:45:52But you crashed on a planet that is foreign to you.

00:45:55You put on your safety suit and observe the environment.

00:45:58The atmosphere is filled with nitrogen and sulfur.

00:46:01You get out and walk around.

00:46:03It has similar gravity to that of Earth.

00:46:06As you venture through the swamp, you start seeing little skin particles similar to those

00:46:11your ship has caught.

00:46:13The liquid below you is some foreign substance that seems to be deteriorating your suit,

00:46:18so you opt to hover.

00:46:20The trees are strange and seem to be living off the atmosphere, but there is no sign of

00:46:25life anywhere.

00:46:26Suddenly, you see a huge crater that leads to the center of the planet.

00:46:31You enter it and see some ships similar to yours.

00:46:35It seems that the Kraken knocked them off course, and they all crash-landed on this

00:46:39planet.

00:46:41Many of them seem to be intact, while others are completely obliterated.

00:46:45Your sensors pick up another reading.

00:46:47It senses another creature dwelling in the center.

00:46:51You try to get closer.

00:46:52You're doing your best to be as gentle as possible, but you feel the ground shaking

00:46:56below you.

00:46:57You duck down and try to avoid the rocks falling overhead.

00:47:01A large tentacle pops out of nowhere, and then another, and another.

00:47:06It swings itself out and crawls in the open.

00:47:09Venus most likely used to be covered with oceans, from 30 to 1,000 feet deep.

00:47:15Also, some water was locked in the soil of the planet.

00:47:18On top of that, Venus had stable temperatures of 68 to 122 degrees Fahrenheit, which, you

00:47:24have to admit, was quite pleasant, and not that different from the temperatures on Earth

00:47:29nowadays.

00:47:30So, what I'm getting at is that for 3 billion years, right until something irrevocable happened

00:47:35700 million years ago, Venus could've been habitable.

00:47:39But now, it's not.

00:47:42The Moon is the second brightest object in our sky.

00:47:45At the same time, among other astronomical bodies, it's one of the dimmest and least

00:47:49reflective.

00:47:51Our natural satellite only seems bright because it's so close to Earth.

00:47:55For comparison, our planet looks much brighter when you look at it from space.

00:47:59It's because clouds, ice, and snow reflect way more light than most types of rock.

00:48:05Triton, Neptune's moon, has all its surface covered with several layers of ice.

00:48:10If this satellite replaced our current moon, the night sky would get 7 times brighter.

00:48:17Even stars are some of the smallest, yet most massive objects in space.

00:48:22They're usually about 12 miles in diameter, but are several times heavier than the Sun.

00:48:26Oh, and they also spin about 600 times per second, far faster than your average figure

00:48:32skater.

00:48:35Saturn is the least dense planet in the Solar System.

00:48:38It has 1-8th the average Earth's density.

00:48:41And still, because of its large volume, the planet is 95 times more massive than Earth.

00:48:48A transient lunar phenomenon is one of the most enigmatic things happening on the Moon.

00:48:53It's a short-lived light, color, or some other change on the satellite's surface.

00:48:58Most commonly, it's random flashes of light.

00:49:01Astronomers have been observing this phenomenon since the 1950s.

00:49:05They've noticed that the flashes occur randomly.

00:49:08Sometimes they can happen several times a week.

00:49:11After that, they disappear for several months.

00:49:14Some of them don't last longer than a couple of minutes, but there have been those that

00:49:17continued for hours.

00:49:20The year was 1969, one day before Apollo 11 landed on the Moon.

00:49:25One of the mission participants noticed that one part of the lunar surface was more illuminated

00:49:30than the surrounding landscape.

00:49:32It looked as if that area had a kind of fluorescence to it.

00:49:35Unfortunately, it's still unclear if this phenomenon was connected with the mysterious

00:49:40lunar flashes.

00:49:42Trash isn't just a problem in Earth's oceans, cities, and forests.

00:49:46There is a thing called space junk, which is any human-made object that's been left

00:49:50in space and now serves no purpose.

00:49:53There's also natural debris from meteoroids and other cosmic objects.

00:49:57There are currently over 500,000 pieces of space debris orbiting the Earth at speeds

00:50:03high enough to cause significant damage if they were to collide with a spacecraft or

00:50:07satellite.

00:50:08It's best to track every single object to ensure that missions outside Earth can reach

00:50:13their destination safely.

00:50:16Our Sun is insanely massive.

00:50:18Want some proof?

00:50:2099.86% of all the mass in the Solar System is the mass of the Sun.

00:50:26In particular, the hydrogen and helium it's made of.

00:50:29The remaining 0.14% is mostly the mass of the Solar System's 8 planets.

00:50:35The Sun's temperature is hotter than the surface of a star.

00:50:39The surface temperature reaches 10,000°F, but the upper atmosphere heats up to millions

00:50:44of degrees.

00:50:46If someone could dig a tunnel straight into the center of the planet and out the opposite

00:50:50side, and you were adventurous enough to jump into it, it would take you 42 minutes to fall

00:50:56to the other side.

00:50:57You'd speed up as you fell, reaching maximum speed by the time you reached Earth's core.

00:51:03After the halfway point, you would then fall upwards, getting slower and slower.

00:51:08By the time you reached the opposite surface, your speed would be back to zero.

00:51:13Unless you managed to climb out of the hole, you'd immediately start falling again, back

00:51:17down or up to the other side of the planet.

00:51:20This trip would go on forever, all thanks to the weird effects of gravity.

00:51:24Hey, might be a fun way to spend an afternoon!

00:51:29There might be more metals, for example, titanium or iron, in lunar craters than astronomers

00:51:35used to think.

00:51:36The main problem with this finding?

00:51:38It contradicts the main theory about how the Moon was formed.

00:51:42That theory says that Earth's natural satellite was spun off from our planet after a collision

00:51:47with a massive space object.

00:51:49But then, why does Earth's metal-poor crust have much less iron oxide than the Moon's?

00:51:55It might mean the Moon was formed from the material lying much deeper inside our planet.

00:52:01Or these metals could've appeared when the molten lunar surface was slowly cooling down.

00:52:07Or maybe, as they've been saying for centuries, it's made of green cheese.

00:52:12Earth could've been purple before it turned blue and green.

00:52:16One scientist has a theory that a substance existed in ancient microbes before chlorophyll

00:52:21– that thing that makes plants green – evolved on Earth.

00:52:24This substance reflected sunlight in red and violet colors, which combined to make purple.

00:52:30If true, the young Earth may have been teeming with strange purple-colored critters before

00:52:35all the green stuff appeared.

00:52:38The highest mountain in the Solar System is Olympus Mons on Mars.

00:52:42It's three times as high as Mount Everest, the Earth's highest mountain above sea level.

00:52:47If you were standing on top of Olympus Mons, you wouldn't understand you were standing

00:52:51on a mountain.

00:52:52Its slopes would be hidden by the planet's curvature.

00:52:57Astronomers have found a massive reservoir of water in space – the largest ever detected.

00:53:02Too bad it's also the farthest – 12 billion light-years away from us.

00:53:07The water vapor cloud holds 140 trillion times as much water as all the Earth's oceans

00:53:12combined.

00:53:13What are we supposed to do with that information?

00:53:16Venus spins at its own unhurried pace.

00:53:19A full rotation takes 243 Earth days, and it takes the planet a bit less than 225 Earth

00:53:26days to go all the way around the Sun.

00:53:28It means a day on Venus is longer than a year.

00:53:32There's very little seismic activity going on inside the Moon.

00:53:36Yet many moonquakes, caused by our planet's gravitational pull, sometimes happen several

00:53:41miles below the surface.

00:53:43After that, tiny cracks and fissures appear in the satellite's surface, and gases escape

00:53:48through them.

00:53:49Hey, they sometimes escape from me, too.

00:53:53Now Mars is the last of the inner planets, which are also called terrestrial since they're

00:53:58made up of rocks and metals.

00:54:00The red planet has a core made mostly of iron, nickel, and sulfur.

00:54:04It's between 900 and 1200 miles across.

00:54:08The core doesn't move.

00:54:09That's why Mars lacks a planet-wide magnetic field.

00:54:13The weak magnetic field it has is just 1,100% of the Earth's.

00:54:20When the planets in the Solar System were just starting to form, Earth didn't have

00:54:24a moon for the longest time.

00:54:26It took 100 million years for our natural satellite to appear.

00:54:30There are several theories as to how the Moon came into existence, but the prevailing

00:54:34one is the fission theory.

00:54:38Somebody went fishing and caught the Moon?

00:54:41Actually no.

00:54:42The fission theory proposes that the Moon was formed when an object collided with Earth,

00:54:47sending particles flying about.

00:54:50Gravity pulled the particles together, and the Moon was created.

00:54:53It eventually settled down on the Earth's ecliptic plane, which is the path that the

00:54:58Moon orbits.

00:54:59Looks like the green cheese is off the table now.

00:55:03The largest single living thing on Earth turns out to be a mushroom in Oregon.

00:55:08This enormous honey mushroom lives in Malheur National Forest and covers an area of 3.7

00:55:13square miles.

00:55:15It could be as much as 8,500 years old.

00:55:18You could be forgiven for missing it, though, since most of it's hidden underground.

00:55:24When the roots of individual honey mushrooms meet, they can fuse together to become a single

00:55:29fungus, which explains how this one got so big.

00:55:33If you could gather all that mushrooming stuff into one big ball, it could weigh as much

00:55:37as 35,000 tons.

00:55:40That's about as heavy as 200 grey whales.

00:55:43Hey, that's a whale of a mushroom.

00:55:47The largest asteroid in the Solar System is called Vesta, and it's so big that it's

00:55:51sometimes even called a dwarf planet.

00:55:54When you look at photos taken from spaceships or the International Space Station that show

00:55:59sunlit objects like Earth or the Moon, something seems wrong.

00:56:04Space looks too empty.

00:56:06No magical scenery of a nighttime sky full of stars.

00:56:10It would be incredibly boring to go stargazing in space, since the sky is always dark.

00:56:16During the daytime, the sky on our home planet is blue because of the diffusion of light.

00:56:21It happens when sunlight goes through the atmosphere, but if you were on the Moon or

00:56:25somewhere else in space, there would be no atmosphere to spread this light around.

00:56:29That's why the sky there would always appear black.

00:56:34But it doesn't mean less bright out there.

00:56:36If you were looking out the window of the space station, you'd see just as much direct

00:56:40sunlight as you would gazing out of your apartment window during a cloudless day.

00:56:45Maybe even more.

00:56:47When taking a picture on a sunny day, you'll probably use a short exposure, together with

00:56:52the narrow aperture setting on your camera.

00:56:54This way, just a short burst of light will get in.

00:56:57That's similar to how our pupils contract in sunlight so that they don't have to deal

00:57:01with too much light.

00:57:03And since it's just as bright up there in space, the process is the same when you take

00:57:07pictures of sunlit objects there.

00:57:10Using short exposure, you can get good, bright pictures of Earth or the surface of the Moon.

00:57:15But it also means there will be no stars in the picture.

00:57:19Even up there, stars are relatively dim.

00:57:21They don't emit enough light to show up in photos taken with such settings.

00:57:26Our home planet has a blue sky that slowly transforms into a beautiful orange-red palette

00:57:31at dusk and dawn.

00:57:33But if you ever get a chance to watch a sunset on Mars, you should expect the opposite, an

00:57:38orange-brown daytime sky that gets a bluish tint at sunset.

00:57:43First of all, Mars is farther away from the Sun than our planet.

00:57:47So when you're looking at the Sun from the Martian surface, of course, it looks fainter

00:57:51and smaller.

00:57:52And not just that, the Sun observed from Mars is just a bluish-white dot surrounded by a

00:57:57blue halo.

00:57:59The thin atmosphere of the red planet contains large dust particles.

00:58:03They create an effect called Mie scattering.

00:58:05It occurs when the diameter of particles in the atmosphere is almost the same as the wavelength

00:58:10of the scattered light.

00:58:12This effect filters out the red light from the Sun's rays, so only the blue light would

00:58:16reach your eyes on Mars.

00:58:20How come Earth doesn't have rings?

00:58:23All gas giants in our solar system, Jupiter, Saturn, Uranus, and Neptune have such rings,

00:58:29whereas the rocky planets Mercury, Venus, Earth, and Mars don't.

00:58:34There are two theories about how rings can appear around a planet.

00:58:38They might be just some material left from the times when the planet was forming, or

00:58:42they may be the remains of a moon that got destroyed by a collision with some space body

00:58:47or torn apart by the strong gravitational pull of its parent planet.

00:58:51The gas giants formed in the outer regions of our solar system, while all the rocky planets

00:58:56are in the inner part.

00:58:57So maybe the inner planets were more protected from potential collisions that could have

00:59:01formed their rings.

00:59:03There are also more moons in the outer regions of our solar system, which could be another

00:59:08reason why the planets there have rings.

00:59:11Also, bigger planets have stronger gravity.

00:59:14It means that they can keep their rings stable after they form.

00:59:18Some experts believe Earth used to have a ring system a long time ago.

00:59:22A Mars-sized object might have collided with our home planet, which probably created a

00:59:27dense ring of debris around it.

00:59:30Some scientists think that this debris formed not a ring but what we know today as the moon.

00:59:37There's probably a giant planet lurking at the edge of the solar system, far beyond Neptune.

00:59:43Scientists call this mysterious hypothetical world Planet 9.

00:59:47If it does exist, it's probably similar to Uranus or Neptune, and 10 times more massive

00:59:52than our home planet.

00:59:54It's likely to circle around the Sun, but in the outer reaches of the solar system,

00:59:58about 20 times farther than Neptune.

01:00:02Another interesting theory says that Planet 9 could actually be a black hole the size

01:00:06of a grapefruit that warps space in a similar way a large planet would.

01:00:13Even though we once thought it was a rare substance in space, water exists all over

01:00:18our solar system.

01:00:19For example, you can often find it in asteroids and comets.

01:00:23It's also in craters on the Moon and Mercury.

01:00:27We still don't know if there's enough water to support potential human colonies if we

01:00:31decide to move there, but some amount of water is definitely present there.

01:00:36Mars has water at its poles too.

01:00:39It's mostly hidden in the layers of ice and probably under the planet's dusty surface.

01:00:44Europa, Jupiter's moon, has some water too.

01:00:47This is the most likely candidate we know about to host life outside Earth.

01:00:52There's probably a whole ocean of liquid water under its frozen surface.

01:00:56It might actually contain twice as much water as all of Earth's oceans combined.

01:01:02Neptune is unexpectedly warm, even though it's 30 times as far from the Sun as our planet

01:01:08and receives less sunlight and heat.

01:01:10But it still radiates way more heat than it gets.

01:01:13It also has way more activity in its atmosphere than you'd suspect, especially if you compare

01:01:18it to its neighbor, Uranus.

01:01:21Both of these planets emit the same amount of heat, even though Uranus is much closer

01:01:26to the Sun.

01:01:27No one knows why.

01:01:29Neptune has extremely strong winds that can reach a speed of up to 1,500 miles per hour.

01:01:35Can they produce this heat?

01:01:37Or maybe it's because of the planet's core or its gravitational force?

01:01:42There's a monster black hole hurtling through space at a speed of 5 million miles per hour.

01:01:48Scientists located it with the Hubble Space Telescope.

01:01:51They believe it weighs as much as a billion suns.

01:01:54It was supposed to stay put in the center of its home galaxy, but some gravitational

01:01:59forces are pushing it around.

01:02:01At one point, this black hole is going to break free from its galaxy and continue roaming

01:02:06the universe.

01:02:07Luckily, it's still 8 billion years away from us.

01:02:11Solar storms are so powerful that they could leave us in complete darkness.

01:02:16Back in July 2012, the strongest solar storm in over 150 years narrowly missed Earth.

01:02:23Coronal Mass Ejections, or CMEs, are large bubbles of ionized gas.

01:02:29They tore through our orbit back then.

01:02:32If they had caught our planet in the crosshairs, we would have literally been in the firing

01:02:36line.

01:02:37We'd have faced solar matter hurtling towards Earth, damaging computers and causing power

01:02:41outages that would have lasted for months.

01:02:45A surprise solar storm hit us on June 25, 2022.

01:02:49One photographer even managed to capture stunning bright auroras that flashed across

01:02:53the dawn sky in Calgary, Canada, and lasted for 5 minutes.

01:02:58They were caused by the storm.

01:03:01Vampire stars are a real thing.

01:03:03They're part of a binary star, and they can literally drain the life out of the other

01:03:07star in the system.

01:03:09No one will hear your cry in space, or something like that.

01:03:13We've all heard this famous chilling phrase, and it's actually true.

01:03:18Space, for the most part, consists of a giant nothingness.

01:03:21There's a lot of, you know, space in space.

01:03:24But this doesn't mean there are no sounds in space.

01:03:27In fact, there are plenty of them.

01:03:29And some of them can even make you shiver.

01:03:31Let's take a look at the scariest space sounds.

01:03:34First of all, how are cosmic sounds even recorded?

01:03:38Sound is just the vibration of molecules.

01:03:40When you scream, you make the molecules push each other furiously until they reach the

01:03:45ear of the person you're yelling at.

01:03:47Then these vibrations get transmitted to the brain, and we recognize them as something

01:03:52that you might need to apologize for.

01:03:55In other words, to hear something, we need molecules.

01:03:58And that's where things get complicated.

01:04:00There aren't any of them in space.

01:04:02The entire universe, almost completely, consists of a vacuum.

01:04:05No, not a hoover.

01:04:08Absolute nothingness.

01:04:09However, the wizards from NASA still record space sounds somehow.

01:04:13So how do they do it?

01:04:15The thing is, there are some types of waves that don't care about molecules.

01:04:19We regular folk can't perceive them without some special devices.

01:04:24These waves include, for example, radio waves.

01:04:26We'll need a radio or something like that to recognize them.

01:04:30And that's exactly what NASA's satellites do.

01:04:32They catch random radio waves.

01:04:35Thanks to their heroism, we can find out how different cosmic bodies sound.

01:04:40These satellites record a variety of waves, fluctuations of plasmas, magnetic fields,

01:04:45and other, you know, stuff.

01:04:47And then scientists from NASA transform all this into normal soundtracks.

01:04:52And some of them sound quite frightening, to put it mildly.

01:04:55Let's take our magnetic field, for example.

01:04:59It surrounds our planet like an invisible shield, protecting us from all sorts of nasties,

01:05:04like radiation and solar winds.

01:05:06But at the same time, we can neither see it, feel it, nor hear.

01:05:10Oops!

01:05:11Well, the last one is outdated.

01:05:13Scientists from the Technical University of Denmark took magnetic waves recorded by the

01:05:17SF Swarm satellite, they converted them into an audio track, and got a pretty creepy result.

01:05:27Now to be honest, it sounds more like an eerie entity stalking you in the middle of the night.

01:05:33But if you remember the maps of Earth's magnetic field, it starts to feel like a spider

01:05:38crawling nearby.

01:05:40And this isn't the first strange sound that we caught on Earth.

01:05:43Recently, we caught another weird radio emission from space.

01:05:47Scientists found out that the repeating signal came from somewhere very far away, like billions

01:05:52of light-years away from us.

01:05:54Such fast radio bursts usually lasted no longer than a few milliseconds, but this one was

01:05:59unique.

01:06:00It lasted about 3 seconds, basically thousands of times longer than usual.

01:06:05And at the same time, the signal was very precise, so much so that scientists even compared

01:06:11it to a heartbeat.

01:06:13Scientists believe that this signal is caused by pulsars, or neutron stars.

01:06:18One time Nikola Tesla caught something similar.

01:06:21But unfortunately, at that time, we didn't know about such things as pulsars, so Tesla

01:06:26was sure that he had caught a message from some extraterrestrial life.

01:06:31It's a pity that the truth turned out to be much more boring.

01:06:34But let's move on from the Earth to the Moon.

01:06:37In 1969, the astronauts of the Apollo 10 mission, the spacecraft that made the final test flight

01:06:43to the Moon, flew past its surface.

01:06:46And then they caught some strange signals coming from the dark side of the Moon, the

01:06:50side that we never see because the Moon is tidally locked to us.

01:06:55The sound was so weird that the astronauts weren't even sure whether to report it to

01:06:59NASA.

01:07:00They were afraid they wouldn't be taken seriously, and maybe even not allowed to participate

01:07:04in the next space missions.

01:07:06Here's what it sounded like.

01:07:12But according to NASA, it's not some creepy extraterrestrial music at all.

01:07:16These may just be some radio waves that affected each other because of their proximity.

01:07:21Although the astronauts who heard it for the first time probably felt a little creeped

01:07:26out.

01:07:27Let's move to the other planets.

01:07:2940 years ago, scientists actively explored the surface of Venus.

01:07:33They sent as many as 10 probes there, which were supposed to capture audio and video shooting

01:07:38from the surface.

01:07:39Now we know what Venus, which could easily destroy us at any attempt to even get close

01:07:44to it, sounds like.

01:07:47Horrifying.

01:07:50And you wouldn't expect anything else from the most dangerous planet in the Solar System.

01:07:55Unfortunately, Venus is even more toxic than the average Twitter user.

01:08:00So these probes didn't last too long.

01:08:02They heroically arrived on a planet and soon broke down.

01:08:06Next one is Jupiter.

01:08:08This space giant, which is 11 times larger than the Earth, never fails to scare us.

01:08:14One of NASA's probes, Juno, flies around Jupiter every few weeks.

01:08:18The probe is moving at a tremendous speed – 130,000 miles per hour.

01:08:23One day, Juno caught one of the strongest invisible signals it had ever encountered.

01:08:28This was the point at which the mad solar wind came into conflict with the magnetic

01:08:33field of Jupiter.

01:08:34It kind of sounded like a cosmic boom.

01:08:38The original sound lasted 2 hours, but it was compressed to a few seconds.

01:08:43It actually sounds more like a collision of a sea wave and a rock.

01:08:47But here, in terms of horror, Jupiter surprisingly loses to one of its small moons, Ganymede.

01:08:54In 2021, the Galileo space probe flew past Ganymede, and during its flight, it received

01:09:00a rather strange recording.

01:09:07These sounds are satellite radiation, and it's unclear whether it sounds like a cozy

01:09:11sunny day in the jungle, or like thousands of bats waiting for you in the night.

01:09:18Next one is Saturn.

01:09:19This signal was caught by the Cassini-Huygens Automatic Interplanetary Station, which was

01:09:24launched into space in 1997.

01:09:26When flying past Saturn, Cassini recorded a pretty scary sound.

01:09:33This terrifying cry of thousands of souls is actually just some radio waves.

01:09:38They aren't too different from what the auroras emit on Earth.

01:09:41A little later, Cassini received another recording.

01:09:44The sound's made by lightning and thunderstorms on Saturn.

01:09:48They sound pretty interesting too.

01:09:52More like popping corn or a Geiger counter, right?

01:09:55But that's just because these lightning strikes have a crazy frequency.

01:10:00Moving on from the Solar System to outer space.

01:10:03The famous Voyager 1 was launched back in 1977, and continues to send us data even 40

01:10:09years after its launch.

01:10:11In 2012, it left the Solar System and entered interstellar space.

01:10:17And then, while abandoning its home, Voyager 1 detected the sound of plasma waves.

01:10:22The original recording lasted 7 months, but fortunately, scientists felt sorry for us

01:10:28and reduced it to 12 seconds.

01:10:31It isn't really eerie, but it's still kind of unsettling.

01:10:35And although it feels like nothing can beat Saturn's horrors, let's end this tournament

01:10:40with one of the scariest objects in the Universe – a black hole.

01:10:44This sound was recorded by the Chandra Space Telescope.

01:10:48While studying a cluster of galaxies in the constellation Perseus, they discovered something

01:10:53strange.

01:10:54Some undulating movements appear from the center of the cluster.

01:10:58They spread out in all directions, like circles on the water.

01:11:03Scientists have suggested that this was caused by a supermassive black hole.

01:11:07The thing is, black holes don't always devour space objects entirely.

01:11:12Sometimes they kind of spit them out.

01:11:15This causes vibrations of gases, which we can convert into soundtracks.

01:11:19What's interesting is that the oscillation of each such wave actually lasts about 10

01:11:25million years.

01:11:26You're just listening to a very accelerated recording.

01:11:30Scientists have reduced the delay between oscillations by about 144 quadrillion times.

01:11:36So let's check it out.

01:11:38This is probably the eeriest sound from the whole list.

01:11:42Nothing too loud or wild, but there's something dark and disturbing about it.

01:11:47Those were the scariest space sounds captured by NASA.

01:11:50To be fair, most of them sounded creepy simply because they're radio waves.

01:11:55But it's still fun to get spooked sometimes.

01:11:58Our Sun is an average-sized star, and still, it could fit 1,300,000 Earths.

01:12:05The star is also 333,000 times as heavy as our planet.

01:12:11NASA has translated radio waves created by planets' atmospheres into audible sounds.

01:12:17That's how astronomers found out that Neptune sounds like ocean waves, Jupiter like being

01:12:23underwater, and Saturn's voice resembles background music to a horror movie.

01:12:28Here on Earth, it's bebop jazz.

01:12:31Now I made that up.

01:12:33The Sun's surface is scorching hot, but a bolt of lightning is 5 times hotter.

01:12:40Earth gets struck by 100 lightning bolts every second, which results in 8 million lightning

01:12:45strikes a day and around 3 billion a year.

01:12:49Ooh, shocking!

01:12:51If you manage to go to the Moon one day and see fresh footprints, that doesn't mean there's

01:12:56someone else there with you.

01:12:59Footprints or similar marks can last for a million years over there.

01:13:03Because the Moon doesn't have an atmosphere.

01:13:06There are no winds, not even a breeze, that can slowly erase those footprints.

01:13:12Astronomers have found the largest hole we've ever seen in the Universe.

01:13:16It's the giant void that spreads a billion light-years across.

01:13:21They found it accidentally.

01:13:23One of the research team members was a little bored and wanted to check how things are going

01:13:27in the direction of the cold spot.

01:13:30That's an anomaly in the Cosmic Microwave Background Map, or CMB for short.

01:13:35It's a faint glow of light that falls on our planet from different directions and fills

01:13:39the Universe.

01:13:41It's been streaming through space for almost 14 billion years as the afterglow that occurred

01:13:46after the Big Bang.

01:13:49So you fall right into the heart of the black hole and prepare for a sad end.

01:13:54Well, you don't have to.

01:13:56Falling into a black hole won't necessarily destroy you or your spaceship.

01:14:01You have to choose a bigger black hole to survive.

01:14:05If you fall into a small black hole, its event horizon is too narrow, and the gravity increases

01:14:10every inch down.

01:14:12So if you extend your arm forward, the gravity on your fingers is much stronger than on your

01:14:17elbow.

01:14:18This will make your hand lengthen, and you'll feel some discomfort.

01:14:22Rather significant, to be honest.

01:14:25Things change if you fall into a supermassive black hole, like the ones in the center of

01:14:29galaxies.

01:14:30They can be millions of times heavier than the Sun.

01:14:34Their event horizon is wide, and the gravity doesn't change as quickly.

01:14:38So the force you'll feel at your heels and at the top of your head will be about the

01:14:42same, and you can go all the way to the heart of the black hole.

01:14:46This myth is busted.

01:14:49If you watch a very touching movie in space and start crying, your tears won't run down.

01:14:55They will gather around the eyeballs.

01:14:58Your eyes will get too dry, so you'll feel like they're burning.

01:15:02Any exposed liquid on your body will vaporize, including the surfaces of your tongue.

01:15:08Speaking of burning, that's one thing fire can't do in space.

01:15:11Fire can spread when there's a flow of oxygen, and since there's not any in space, well…

01:15:19Once they explode, stars aren't supposed to come back to life.

01:15:23But some of the stars somehow have survived the Great Supernova Explosion.

01:15:28Such zombie stars are pretty rare.

01:15:31Scientists found a really big one, called LP40365.

01:15:34It's a partially burnt white dwarf.

01:15:38A white dwarf is a star that burned up all of the hydrogen, and that hydrogen was previously

01:15:43its nuclear fuel.

01:15:46In this case, the final explosion was maybe weaker than it usually is, not powerful enough

01:15:51to destroy the entire star.

01:15:54It's like a star wanted to explode but didn't make it, which is why part of the matter still

01:15:59survived.

01:16:01If you ever go into space, don't take off your spacesuit unless you're on a spaceship.

01:16:06Air in your lungs would expand, as well as the oxygen in the rest of your body.

01:16:11You'd be like a balloon, twice your regular size.

01:16:15Good news, the skin is elastic enough to hold you together, which means you wouldn't explode.

01:16:20Small comfort.

01:16:22When something goes into a black hole, it changes shape and gets stretched out just

01:16:27like spaghetti.

01:16:28This happens because gravitational force is trying to stretch an object in one direction,

01:16:33but at the same time squeeze it into another, like a pasta paradox.

01:16:39Speaking of, a black hole that's as big as a single atom has the mass of a really big

01:16:44mountain.

01:16:45There's one at the center of the Milky Way called Sagittarius A. It has a mass like for

01:16:51a billion suns, but luckily, it's far away from us.

01:16:57If you made a big boom on an asteroid, you'd never be able to hear its loud sound.

01:17:02Yes, we often hear the sound of spaceships and battles in space in the movies, but that's

01:17:07just a myth.

01:17:10Sound is a wave that spreads because of the vibrations of molecules.

01:17:14A person claps a few feet away from you, the sound wave begins to push the first air molecule

01:17:19next to the clap, then the second, third, and so on until the wave reaches your ear.

01:17:25So to spread sound, we need molecules like air or water.

01:17:29In our atmosphere, sound waves spread out just fine, but space is a vacuum, so it's

01:17:35nothing here.

01:17:36You can clap your hands loudly there, but there just won't be any molecules that can

01:17:40vibrate and carry that sound.

01:17:43So to carry on a conversation, you'd either need a radio or really good lip-reading skills.

01:17:51Meteoroids orbit the Sun, while the majority of human-made debris orbits our planet.

01:17:56For example, we launched almost 9,000 spacecraft around the world from satellites to rocketships.

01:18:03Even the tiniest pieces can damage a spacecraft at such high speeds.

01:18:08Galaxies, planets, comets, asteroids, stars, space bodies are things we can actually see

01:18:14in space.

01:18:16But they make up less than 5% of the total Universe.

01:18:20Dark matter, one of the biggest mysteries in space, is the name we use for all the mass

01:18:25in the Universe that's still invisible to us.

01:18:28And there's a lot of it.

01:18:29It may even make 25% of the Universe.

01:18:33Dark energy makes the other 70% of the Universe.

01:18:36Hmm, that adds up to 100, right?

01:18:40Now let's look at the Moon.

01:18:42It always looked at us with one side.

01:18:44This means the Moon has a dark side, and the Sun's rays never get there.

01:18:49Well, that's a myth.

01:18:51The whole point is that the Moon is gravitationally locked to the Earth.

01:18:55There are days and nights there too.

01:18:57It's just that this rotation is perfectly aligned with the rotation of the Earth.

01:19:02So whenever you look at the Moon, you only see one side.

01:19:06Although there are days when the Sun shines there too, so it's not the dark side, it's

01:19:10the far side.

01:19:12And we even have pictures of this place.

01:19:15And there's one of the biggest craters in our entire solar system, the South Pole-Aitken

01:19:20Basin.

01:19:21It's as wide as two states of Texas.

01:19:23Yeehaw!

01:19:24One myth that turned out to be untrue is that people have never actually been on the Moon.

01:19:32This is the original space suit of the first astronauts who were there.

01:19:36Look at the sole of the shoe.

01:19:38Some people claim there's no way they could've left footprints like this there.

01:19:42Actually they could.

01:19:43On the Moon, the astronauts wore extra boots over their suits, and their soles matched

01:19:48the footprints on the Moon perfectly.

01:19:51The astronauts didn't need them when they left the Moon and tossed them when the Moon

01:19:55walk was over.

01:19:56They left a lot of stuff there too.

01:19:58They even tossed the armrests of the seats in the lunar module to reduce the weight.

01:20:03Now, counting all the Apollo lunar missions, the total weight of rubbish on the Moon is

01:20:08approximately 187 tons, including several lunar rovers, spacecraft debris, 6 lunar modules,

01:20:16and all the experiments left behind.

01:20:18That's like 3 Boeing 737s.

01:20:22Another myth about the Sun is that it's yellow.

01:20:25Let's send you into space for this one.

01:20:27You look out the window, and… it's white!

01:20:29The Sun only appears yellow to us through the filter of our atmosphere.

01:20:34The composition of the air and its thickness just distorts the light of the star.

01:20:39But stars do come in different colors.

01:20:41Cooler stars have bright orange and red colors.

01:20:45In space, no one can hear you scream.

01:20:48Or is that, in space, no one can hear ice cream?

01:20:51Well, either way, we know that no supernovas, crashing asteroids, and burning planets make

01:20:56a sound in space.

01:20:58Or do they?

01:21:00What if you actually can hear something out there?

01:21:02Well, let's see.

01:21:04Okie dokie, back to middle school.

01:21:07Sound is a mechanical wave originating from vibration.

01:21:11What exactly does that mean?

01:21:13The simplest example is guitar strings.

01:21:16Let's pluck one of them.

01:21:17It starts to vibrate.

01:21:19The atoms inside the metal string begin to push and beat the atoms of the air around

01:21:23them.

01:21:24So now, atoms are constantly pushing each other until they reach our ears.

01:21:28It's like a wave from a pebble thrown into a pond, and it happens very quickly, at a

01:21:33speed of about 761 mph.

01:21:38Then our eardrums begin to vibrate at the same frequency.

01:21:41And the little bones inside our ears transmit this vibration to the brain.

01:21:46The brain then does its magic, recognizes the pattern, and turns it into sounds.

01:21:52Great!

01:21:54Now we know that we need some particles to create sound.

01:21:57And we can find these particles in gases, liquids, and solid substances.

01:22:02And what about space?

01:22:04Nope, it's almost a perfect vacuum.

01:22:06And you've probably already heard that there's no sound in space because it's a vacuum.

01:22:12But what does it actually mean?

01:22:14Well, a vacuum is a perfect void.

01:22:17It's an area completely devoid of matter.

01:22:20It means there's nothing there.

01:22:22Yeah.

01:22:23Despite all those celestial bodies in space, there's actually no air in between them.

01:22:27No atoms, no particles, nothing.

01:22:30Nada.

01:22:31Zippo.

01:22:32Well, almost.

01:22:33To be honest, the perfect vacuum doesn't really exist.

01:22:37We can't get rid of atoms for good.

01:22:39But space is very close to this notion.

01:22:41On average, there are 15 to 80 atoms per 1 cubic inch.

01:22:46This may sound like a big number, but keep in mind that these atoms are tiny, and the

01:22:51void distance between them is huge.

01:22:54For comparison, 1 cubic inch of air contains about 16,000 atoms.

01:22:59So of course, with such a low density, these atoms can't push each other.

01:23:04Even if the vibration is very strong, like, I don't know, a supernova, they still won't

01:23:09be able to do that.

01:23:11So, movies have been lying to us.

01:23:14All these epic space scenes actually take place in an awkward silence.

01:23:18Who would've guessed?

01:23:22But don't get upset.

01:23:23What if I tell you there are, in fact, some ways to hear sound in space?

01:23:29First of all, there's still sound on other planets.

01:23:32If there's an atmosphere on a space body, or at least something like gas, water, or

01:23:37a solid surface, there will be sound.

01:23:40In our case, the atmosphere becomes completely silent at about 60 miles above the Earth's

01:23:46surface.

01:23:47That's where the sky stops being blue, and a black starry veil begins.

01:23:53In any case, we'd have to land on another planet, or at least get close to its atmosphere

01:23:58to hear something.

01:24:00But whatever it is, it would sound very different.

01:24:03Let's take our favorite Venus as an example.

01:24:06The atmosphere there is very dense.

01:24:09Scientists jokingly call it a thick chemical soup.

01:24:12No thanks.

01:24:13So, if you somehow manage to stay alive and speak there, your voice would be very different.

01:24:19It would become much louder, and it would sound DEEPER.

01:24:24So if you want a pleasant baritone, you know what to do.

01:24:29I wonder what would happen if Earth had a denser atmosphere.

01:24:32What would we hear then?

01:24:34Well, you can vaguely imagine that if you've ever been in the water.

01:24:39Water is very dense.

01:24:41Sound moves there much faster and better compared to the air, at a speed of almost a mile per

01:24:46second depending on the water temperature.

01:24:50So if you sit in an empty room with no sound sources, you won't hear much, right?

01:24:55Now dip your head in the water and check out how the same silence sounds here.

01:25:00It's not quiet at all.

01:25:02Even if you ignore the ever-present sounds of the water itself, you'll immediately notice

01:25:06how well you can hear your own body, how your blood pulsates in the veins, how your heart

01:25:12works, the slightest movement of your fingers.

01:25:14Kinda creepy, isn't it?

01:25:17This gives us an idea of what would happen to us on a planet with a denser atmosphere.

01:25:21And that's just crazy.

01:25:22We would hear everything.

01:25:25From scurrying animals to the movement of tectonic plates.

01:25:28Ah, come on, you'd probably say.

01:25:31It's obvious that there's sound on other planets.

01:25:34But didn't you say we can hear something in open space?

01:25:38Actually yes.

01:25:39For example, in a cloud of dust.

01:25:41You can find space dust almost everywhere in space.

01:25:44It may be the remains of a star or something else.

01:25:48And in these places, everything is a bit denser than usual.

01:25:52This means there are probably dust clouds where particles are very close to each other,

01:25:56which means they can produce sounds.

01:25:58Of course, those will be very quiet and transmitted over a very short distance.

01:26:05But it's better than nothing, right?

01:26:08Plus, we already have one real space sound recorded.

01:26:12It came from the Perseus galaxy, which is located 250 million light-years away from

01:26:17us.

01:26:18NASA recorded it in 2003.

01:26:21Those of us music geeks will want to know that it's a B-flat, 57 octaves below middle

01:26:27C on the piano.

01:26:28You'd have to add another 660 keys to the left on the keyboard.

01:26:33But its frequency is so low that the human ear, unfortunately, can't hear it.

01:26:39Besides that, we can only hear something inside spaceships.

01:26:43These are small pockets of air, after all.

01:26:46In a spacesuit, you would hear sounds very well too, including your breathing or blood

01:26:51circulation in a spacesuit.

01:26:54But two astronauts, flying side by side, wouldn't hear each other, even if they got very close

01:26:59and shouted very loudly.

01:27:00It's quite funny, if you, being an astronaut, bumped into something, it would be very loud

01:27:06for you, but your friend wouldn't hear anything.

01:27:09That's why astronauts use radio devices.

01:27:15Now purely theoretically, if you could somehow crawl out of your spacesuit and survive, you'd

01:27:22be able to hear the chatter and noises going on inside the spaceship.

01:27:26But how?

01:27:27So, look, we have some air inside the spaceship, and it transmits sound.

01:27:31It reaches the metal casing and gets through it.

01:27:34And then, if you leaned against the ship, preferably touching it with your elbow or

01:27:39knee, the sound would be transmitted to the brain directly through your bones, ignoring

01:27:44the ears.

01:27:45Yes, our bones conduct sound.

01:27:49That's how, for example, deaf people listen to music.

01:27:52It's called bone conduction.

01:27:54It's used in some headphones and some other technologies.

01:27:57You can do a little experiment.

01:27:59Hold your fingers over your ears.

01:28:01Tuck them properly so that you really don't hear much.

01:28:04Then try to touch a sound source.

01:28:07It can be anything vibrating.

01:28:08For example, a speaker playing music with some part of your body where the bone is close

01:28:13to the skin.

01:28:14Now watch the miracle happen.

01:28:17You can hear the sound not through your ears, but directly in your brain.

01:28:21But please don't repeat this experiment in open space, you know, ice cream, haha!

01:28:27Now you've probably heard about things like the sounds of space, where you can listen,

01:28:32for example, to the sounds made by the Sun or different planets.

01:28:36How do we record these ones?

01:28:38Easily.

01:28:39There is another way to hear sound in space – electromagnetic waves.

01:28:44It was January 7th in 1610 when Italian astronomer Galileo Galilei made an astonishing discovery

01:28:52using his homemade telescope.

01:28:55Four moons orbiting the planet Jupiter.

01:28:58By the way, these days you can make your own version of his telescope using cardboard tubes,

01:29:03lenses, and some superglue.

01:29:06The main point of this DIY telescope is to place two lenses at the correct distance from

01:29:11each other.

01:29:12You'll need two lenses.

01:29:13One lens should be concave, the other one convex.

01:29:17So one lens is curved out and the other one is curved in.

01:29:21Galileo's initial telescope was able to magnify objects approximately 8 times.

01:29:27He continued to improve it until it reached about 20 times the magnifying power.

01:29:33But let's get back to the main story, shall we?

01:29:37When he first looked at those four moons of Jupiter, he believed he was simply looking

01:29:41at a bunch of stars.

01:29:43But he soon noticed that these space objects seemed to be moving in a regular pattern.

01:29:48It took him a couple of weeks to figure out that what he was looking at were not stars,

01:29:54but moons circling Jupiter.

01:29:57Galileo initially named those moons 1, 2, 3, and 4.

01:30:03But let's face it, those weren't the most creative names.

01:30:06As more moons in our galaxy were discovered later, the numerical system for naming them

01:30:11became confusing and impractical, so it lasted for just a few centuries.

01:30:16So these days, those four satellites, Jupiter's largest, are named Io, Europa, Ganymede, and Callisto.

01:30:26They're collectively known as the Galilean moons to honor the man who first noticed them.

01:30:32Galileo's discovery was crucial for our later understanding of astronomy.

01:30:36It was initially believed that other objects revolved around the Earth since it was seen

01:30:41as the center of the universe.

01:30:45We now know that there are hundreds of moons in our solar system, however, large moons

01:30:50like those discovered by Galileo Galilei are not so commonly stumbled upon.

01:30:55A moon is considered large when it's the size of our planet or bigger.

01:31:00Ganymede, for instance, is bigger than Mercury.

01:31:04We basically call Ganymede a moon just because it orbits Jupiter.

01:31:08Otherwise, it has all the other characteristics of a planet.

01:31:12It's no surprise that Jupiter has the biggest moons in the area.

01:31:16It beats all the other planets in our solar system in both size and mass.

01:31:21So no wonder it pulled in a lot of other objects towards it.

01:31:25Jupiter is believed to have in total almost 80 moons, with only 53 of them being given

01:31:31official names until today.

01:31:35The first of those Jupiterian moons to be discovered by Galileo was Io.

01:31:40What sets it apart is the fact that it has a lot of volcanoes.

01:31:44Io is the only space object to have active volcanoes in our solar system, apart from

01:31:49Earth.

01:31:50It's also nicknamed the moon of fire and ice because of its sulfur dioxide snow fields.

01:31:57Io's outer layer is splotchy, featuring multiple colors like orange, black, yellow,

01:32:03white, and red.

01:32:04That's probably the reason why NASA described it as a giant pizza covered with melted cheese,

01:32:10and splotches of tomato and ripe olives.

01:32:14Because of that sulfur though, Io doesn't smell that appetizing, something similar to

01:32:19a rotten egg.

01:32:22There are more than 100 mountains on the surface of this moon.

01:32:26They are a lot larger than those we see on Earth, some being bigger than Mount Everest.

01:32:31On average, these mountains are 4 miles tall and 98 miles long.

01:32:39Because of those active volcanoes and the intense radiation on Io, there's little

01:32:43chance that life as we know it could exist here.

01:32:46But hey, who's to say it can't have life the way we don't know it?

01:32:52Next on the list of Galilean moons is Europa, the smallest of the four.

01:32:57It's comparable in size to the moon.

01:32:59Europa has an entirely icy surface, with just a bunch of craters scattered here and there.

01:33:05Because of that outer layer, Europa is very reflective, making it one of the brightest

01:33:10moons out there.

01:33:11As for its age, scientists believe its surface to be somewhere between 20 to 180 million

01:33:18years old.

01:33:20Europa is about 4.5 billion years old.

01:33:26What lies beneath that icy surface is impressive.

01:33:29It may even hold the secret to life outside Earth.

01:33:33Ice forms here in two ways.

01:33:35The first is through congelation, a rather self-explanatory process.

01:33:40Ice just grows as the surrounding environment gets colder and colder.

01:33:45The other method, though, is a lot more fascinating.

01:33:48A layer of supercooled water found under the ice shell reacts when agitated.

01:33:53It then generates these crystals that make it look like it's snowing in reverse, floating

01:33:58upwards to the ice sheet they sit under.

01:34:02You can recreate this environment yourself at home.

01:34:05Take a bottle of purified water and place it into the freezer.

01:34:09If you don't have purified water anywhere near, just boil some water a couple of times

01:34:13to get rid of as many impurities as possible.

01:34:16Since there won't be any particles inside, once in the freezer, it won't turn solid.

01:34:23But if you take the bottle out of the freezer and give it a shake, the impact will make

01:34:27the water rapidly crystallize, transforming it into a slush-like consistency.

01:34:32There may be water on Europa, but there's little evidence so far that life exists on

01:34:37this moon.

01:34:38However, it's one of the highest candidates in the solar system for potential habitability.

01:34:44Some sort of life forms could adapt to live there in its under-ice ocean.

01:34:49That environment is most likely similar to what we can find in our planet's hydrothermal

01:34:53vents hidden deep within our oceans.

01:34:57The amount of oxygen in Europa's atmosphere is very little, but in 2013, NASA gave away

01:35:04some cool evidence.

01:35:06This yet again supports the theory that there is potential for life on this moon.

01:35:10It seems that Europa might be venting water into space.

01:35:15If this is confirmed by future observations, it could also mean that Europa is geologically

01:35:20active.

01:35:22It could also come in handy if we'd manage to study water sources one day.

01:35:28The largest of those Galilean moons is Ganymede.

01:35:31It's also the biggest moon in our solar system altogether.

01:35:35It's a low-density space object similar to Mercury in size, but having only half of its

01:35:40mass.

01:35:41However, Ganymede is the only moon out there to feature its own magnetic field.

01:35:47It's quite small though, and we can barely notice it from Earth since it's overshadowed

01:35:51by Jupiter's much more powerful magnetic field.

01:35:55Another cool aspect of Ganymede is that its atmosphere contains oxygen.

01:36:00Don't get too excited, it's not nearly enough to support any lifeforms living there.

01:36:06Back in December 2021, a 50-second audio clip was released, which was previously recorded

01:36:12by NASA's probe on its Ganymede flyby.

01:36:17For the inexperienced, the sounds were more similar to those of an old dial-up internet

01:36:21connection.

01:36:22But because of its quirky tunes, Ganymede was soon nicknamed Jupiter's singing moon.

01:36:29Finishing up the list of Galilean moons is Callisto, or the most heavily cratered object

01:36:34in our solar system.

01:36:37What's interesting about this moon is that its landscape has barely changed since it

01:36:41formed, and scientists are still debating why this is happening.

01:36:46Most other space objects go through loads of changes throughout their lifetimes because

01:36:50of events such as collisions with other objects, changes in orientation or speed, or chemical

01:36:57reactions happening on their surface.

01:37:00Callisto is also about the size of the planet Mercury, but it has a lower density.

01:37:06Jupiter's magnetic field has a lesser impact here since Callisto is the furthest from the

01:37:11giant planet.

01:37:12Its surface is estimated to be a staggering 4 billion years old.

01:37:18As opposed to Io, Callisto is not geologically active, but scientists believe there might

01:37:24be an ocean hiding underneath the moon's surface, which may potentially harbor life.

01:37:30The fact that it's less impacted by Jupiter's magnetic field means that it features low

01:37:35levels of radiation.

01:37:37Given this suitable environment, we may one day end up setting a human base for future

01:37:42explorations here.

01:37:46The infinite vasts of the universe hold endless possibilities and secrets.

01:37:52And here's one of the intriguing questions.

01:37:54How life, and we as humans, would look like on other planets?

01:37:59Imagine a world where the laws of physics, the environment, and the conditions are vastly

01:38:04different from what we're used to.

01:38:07How would we adapt and evolve to survive in these strange new lands?

01:38:11Let's see.

01:38:13Mercury is the closest planet to the sun and has a thin atmosphere.

01:38:17The temperatures there are extreme, with the day side reaching over 800 degrees Fahrenheit

01:38:23and the night side dropping to negative 290 degrees Fahrenheit.

01:38:28So what can we do to survive these crazy temperatures and constant solar radiation?

01:38:34Maybe we can magically turn into metal.

01:38:36For example, titanium and platinum can perfectly tolerate high temperatures.

01:38:42But seriously though, there is an option.

01:38:44We could settle underground, where the temperatures aren't so frenzied.

01:38:48If we lived underground, we might evolve with large eyes to better capture light.

01:38:53We might also evolve thicker skin to protect ourselves from the intense radiation.

01:38:59Basically, we have two options.

01:39:01Become metal or become moles.

01:39:04Let's move on to Venus.

01:39:06This planet is extremely hostile.

01:39:09First of all, Venus is known for its thick, more toxic-than-your-ex type of atmosphere.

01:39:14The whole planet is covered with carbon dioxide and its surface is absolutely dry, making

01:39:20it incredibly hot.

01:39:22The average temperature is around 847 degrees Fahrenheit, making it one of the hottest planets

01:39:28in our solar system.

01:39:29Also, don't forget about the crazy pressure.

01:39:33Living on Venus would be like standing 3,000 feet underwater.

01:39:37Only particular hardy microbes from Earth could survive in such conditions.

01:39:42So if you want to live on Venus, you might have to become a microbe.

01:39:46But unfortunately, since we're not microbes, we have to wear special gear and equipment

01:39:51to survive there.

01:39:53Maybe we'd have to develop a heat-resistant exoskeleton to protect ourselves, as well

01:39:58as get some new lungs that can filter out the toxic elements in the atmosphere.

01:40:03Let's talk about our favorite red sibling, Mars.

01:40:06The first noticeable change after a few hundred years would be your new skeleton.

01:40:11The gravity on Mars is much weaker than on Earth, so your muscles and bones would shrink.

01:40:17To make up for this difference, you'd have to eat more and probably start going to the

01:40:21gym.

01:40:22Also, you'd have to adapt to the low atmospheric pressure and colder temperatures.

01:40:27You need to retain heat, right?

01:40:29That means you'd need a thicker layer of body fat.

01:40:32Sorry folks, but on Mars, we might become fatter.

01:40:36Another reason to start working out.

01:40:39Another big change would occur in your skin.

01:40:41Your skin is like a big barrier that protects you from harmful things such as bacteria,

01:40:46UV light, looking totally creepy, and so on.

01:40:50So what would happen to it?

01:40:52Most likely, you would turn orange, due to the carotenoids.

01:40:57Carotenoids are a type of nutrient that you get from foods such as carrots, potatoes,

01:41:01tomatoes, and so on.

01:41:03They protect very well against ultraviolet radiation on Mars.

01:41:07They only have one downside.

01:41:09By eating a lot of pumpkins from the Martian farmer's market, you'll gradually start

01:41:13to turn orange.

01:41:14But maybe it's not so bad.

01:41:17Maybe life on Jupiter would be easier.

01:41:19Yeah, no.

01:41:20It has no solid land.

01:41:22This planet is made up of hydrogen and helium and is referred to as a gas giant.

01:41:28You would simply float there, like in a huge cloud.

01:41:31And even if you managed to land and try to walk, it would be like moving through a super

01:41:35thick fog.

01:41:37So how would we evolve there?

01:41:38Firstly, we might become much larger in size to withstand the immense pressures.

01:41:43Secondly, the temperature fluctuations on Jupiter are enormous.

01:41:48The surface is terrifyingly cold and the temperature rises significantly under the outer layers

01:41:54of the atmosphere.

01:41:55Thirdly, if you lived on Jupiter, there would be no verbal language.

01:41:59This gas giant absorbs radio waves, so even if you were speaking, no one would hear you.

01:42:05There would be no music either, so no parties.

01:42:07And what's the point then?

01:42:09Hey, maybe we could communicate with sign language, but that's not so simple either.

01:42:14Jupiter is full of wild winds and storm clouds, so it's unlikely you would be able to see

01:42:19anything.

01:42:20So even if we evolved there in some way, our lives would still not be easy.

01:42:26Before landing on Saturn, you would probably want to check out its iconic rings.

01:42:30But you wouldn't be able to do that because Saturn's rings consist of a bunch of ice particles

01:42:34flying in space, so it would be extremely hard to land.

01:42:39So let's go straight to Saturn itself.

01:42:42At first, it may seem that Saturn is not bad for us.

01:42:45Some layers of this gas giant have quite pleasant temperatures.

01:42:48If we dive deeper into Saturn, it gets surprisingly warm, up to 26 degrees Fahrenheit in its second

01:42:55layer.

01:42:56This is an average temperature in countries like Sweden and Canada.

01:43:00But unfortunately, this is only one such layer.

01:43:04The rest of the planet is incredibly cold, so in order to survive on Saturn, we'd have

01:43:08to do a lot of work.

01:43:11In addition to the cold, we'd have to deal with the planet's harsh environment, including

01:43:15its intense storms, strong winds, and radiation.

01:43:18To protect ourselves from these conditions, we'd need to evolve tough skin, again, find

01:43:24some insulation, and so on.

01:43:27Next planet is Uranus.

01:43:29Uranus has a very different environment from Earth, with much colder temperatures, a lack

01:43:34of a solid surface, and a much different atmosphere.

01:43:37It's like another Jupiter, but with blue vibes.

01:43:40It's not that bad, though.

01:43:41There's even water on Uranus.

01:43:43The only problem is, the planet is full of ammonia, that nasty stuff we use for cleaning.

01:43:47So don't be surprised if you feel the gross smell.

01:43:50Also, it's incredibly cold out there, almost like a never-ending winter.

01:43:55So what would it be like to survive in such a dark and harsh environment?

01:43:59We'd need thicker skin, again, to cope with extreme temperatures.

01:44:03And again, we'd need larger eyes to see better in all this darkness.

01:44:07We might even have to develop a new hearing system, like that of dolphins.

01:44:11Wouldn't that be fun?

01:44:13Let's move on to Neptune.

01:44:15If human beings were to evolve on Neptune, they would need to adapt to its harsh conditions.

01:44:20Neptune, the 8th and farthest planet from our sun, is another gas giant.

01:44:26The only difference is, this planet may have a solid core.

01:44:30If we were to live on Neptune, we'd need to float or swim in its methane-rich atmosphere.

01:44:35We'd also need to develop gills or something like that in order to breathe.

01:44:39Basically, we'd turn into space reptiles or cosmic fishes.

01:44:44The gravity on Neptune is slightly stronger than Earth's, but strong winds make it difficult

01:44:48to stand in one place.

01:44:50To withstand the wind, we'd need to be much heavier.

01:44:54Once again, you'd need to eat a lot and pump up some muscles.

01:44:58Yeah, yeah, technically it's not a planet, but we still love it and can't forget it.

01:45:03A small, distant, and incredibly cold world, Pluto's even smaller than our moon.

01:45:09And because of that, there's almost no gravity there.

01:45:12It will be extremely difficult to stand on it.

01:45:14To avoid accidentally flying into outer space while playing football, we'd need to create

01:45:19a fake gravity machine.

01:45:21And if we don't want to feel dizzy, we'd need to evolve a brand new nervous system.

01:45:25But Pluto isn't all that bad.

01:45:27For example, there's liquid water under the surface, and even some icy mountains.

01:45:32Maybe it would be possible to survive there if we had some serious equipment, clothes,

01:45:37supplies, and… nah, too much hassle.

01:45:40Anyway, from the scorching heat of Mercury to the freezing temperatures of Neptune, each

01:45:44planet has a unique set of environmental challenges and opportunities for evolution.

01:45:50While we may never truly know what humans would look like on these other worlds, it's

01:45:54exciting to consider the endless possibilities.

01:45:57Never stop looking at the stars and asking these questions!

01:46:01The center of the Milky Way is a story of intense radiation, gravity, and mystery.

01:46:07A place where the forces of nature are pushed to their limits.

01:46:11But what if our own planet were to find itself in this cosmic theater?

01:46:16What would happen if the Earth were located there and somehow managed to survive?

01:46:21Let's start this journey to the heart of our galaxy and find out!

01:46:27Picture this.

01:46:28You're floating in space, surrounded by billions and billions of stars.

01:46:33Suddenly, you see a bright swirling mass of gas and dust in the distance.

01:46:39That my friend, is the Milky Way galaxy, our home in the vast expanse of the universe.

01:46:46The Milky Way is estimated to contain over 100 billion stars, and is about 100,000 light

01:46:53years across.

01:46:55In other words, if you were traveling at the speed of light, it would take you 100,000

01:46:59years to cross the Milky Way from one end to the other.

01:47:02It's a couple trillions of miles.

01:47:06And it isn't just a static collection of stars and gas.

01:47:09It's a dynamic, evolving system.

01:47:12In fact, the Milky Way is currently hurtling through space at a speed of about 1.3 million

01:47:18miles per hour.

01:47:21One of the most fascinating things about our galaxy is its shape.

01:47:25The Milky Way is a spiral galaxy, which means that it kinda looks like a disc, with a central

01:47:30bulge and spiral arms.

01:47:33The spiral arms are the areas where new stars are born.

01:47:36It's where the most stars, gas and dust are concentrated.

01:47:41And this is where the solar system is located.

01:47:45Our system is like a tiny speck in the grand cosmic tapestry of the Milky Way.

01:47:51It's about 26,000 light years away from the center of the galaxy.

01:47:55A pretty long distance, isn't it?

01:47:58The solar system is also moving through the Milky Way as it orbits around the galactic

01:48:04center.

01:48:05It takes about 230 million years for our system to make one complete orbit around the galaxy.

01:48:12Just imagine that!

01:48:14Since the time of the dinosaurs, we've traveled just a quarter of this way.

01:48:19The position of the solar system in the galaxy affects our life in many ways.

01:48:24For example, things like the amount of radiation and cosmic rays we're exposed to, and even

01:48:31the likelihood of asteroid impacts, and so on.

01:48:35Also, thanks to our location, we can enjoy some pretty amazing views of the universe

01:48:41around us.

01:48:42From our vantage point in the Milky Way, we're able to see other galaxies, nebulae, and star

01:48:48clusters in breathtaking detail.

01:48:51We're also a part of a pretty happening neighborhood, with lots of other stars and planets nearby.

01:48:57So we're lucky fellas!

01:49:00But what would happen if we weren't so lucky?

01:49:02What if the Earth was located in the center of the Milky Way instead?

01:49:07The center of the Milky Way is home to a region of space called the Central Bulge, and it's

01:49:13just packed with stars.

01:49:15It's like a disco ball, but instead of shiny mirrors, it's covered in stars.

01:49:21Only this disco ball is really huge, about 10,000 light years in diameter.

01:49:27The center of the Milky Way is also home to some extreme environments that would make

01:49:32even the bravest astronauts shiver.

01:49:35High energy particles and intense magnetic fields can wreak havoc on electronics and

01:49:40spacecraft.

01:49:42These radiation fields can fry anything in their path, so it's not exactly a friendly

01:49:47place for life as we know it.

01:49:50So if the Earth were located somewhere closer to the center of the Milky Way galaxy, it

01:49:55would be a very different place.

01:49:59Let's take a look at some of the potential effects.

01:50:03First of all, radiation.

01:50:05As we mentioned earlier, the center of the Milky Way is one of the most radiation-dense

01:50:10regions in the galaxy.

01:50:12It would make life on Earth very challenging, if not impossible.

01:50:16Sure, we have the Earth's magnetic field.

01:50:20It's like a giant shield that protects us from harmful radiation from outer space.

01:50:25But could it protect us if we were located in the center of the Milky Way?

01:50:29Unfortunately, the answer is no.

01:50:32It's kind of like trying to use a tiny umbrella to protect yourself from a massive storm.

01:50:38So it would be an easy win for the galaxy.

01:50:42But it's not all doom and gloom.

01:50:44There are some brave organisms that are able to adapt to high levels of radiation.

01:50:50We've seen that life on Earth has evolved to survive anywhere, from the depths of the

01:50:55ocean to the icy poles of the planet.

01:50:59So let's imagine what would happen if we somehow evolved to survive in these harsh

01:51:05conditions.

01:51:06Like, picture humans with tough, scaly skin that protects them from radiation, and plants

01:51:12with unique structures that allow them to thrive in this bright environment.

01:51:17In that case, radiation could still have some seriously spooky effects on us.

01:51:23For example, it could damage DNA molecules and cause mutations.

01:51:28Imagine a world where plants grow with five leaves instead of four, animals have strangely

01:51:32colored fur, or people have unusual eye colors or other unique features.

01:51:38And these are just some of the best examples.

01:51:41Let's not dive into the bad ones.

01:51:44Also, it could cause us to undergo some metabolic changes.

01:51:48Maybe our bodies could process food and other resources more quickly, which could lead to

01:51:54faster growth rates and larger sizes.

01:51:57Plants could grow tall and thick, and animals would be much larger than usual.

01:52:03There are also some organisms on Earth that are able to bioluminesce.

01:52:09Thanks to high levels of radiation, these organisms could potentially glow even brighter

01:52:13than usual.

01:52:16Imagine walking through a forest at night and seeing trees, mushrooms, and even insects

01:52:21glowing with an eerie blue or green light.

01:52:24Frightening and amazing, isn't it?

01:52:27But let's move on to the next big change, gravity.

01:52:31The gravity in the center of the Milky Way is incredibly strong, all thanks to a super

01:52:36massive black hole, which is about 4 million times the mass of the Sun.

01:52:42This black hole is called Sagittarius A. And yep, it's our neighbor now, great.

01:52:49And assuming we don't get swallowed by this black hole or crushed by this incredibly

01:52:54strong gravity, it still could trigger lots of earthquakes and volcanic eruptions.

01:53:00This black hole would be like the gravitational bully, pulling and tugging at everything in

01:53:05its path.

01:53:06Basically, if we survived this, we'd have an epic surfing competition every single day.

01:53:13Just add a bit of the thrill of risking your life, and forget about running away from the

01:53:17planet.

01:53:18No easy rocket launches anymore.

01:53:21And physical objects won't be the only ones affected by gravity.

01:53:25Time would flow very differently for us.

01:53:28According to Einstein's theory of relativity, time passes more slowly in areas of high gravity.

01:53:35In other words, earthlings would age more slowly than someone far from the center of

01:53:40our galaxy.

01:53:41Also, the center of the Milky Way is a very busy place.

01:53:46Stars, planets, and other celestial objects moving around at incredibly high speeds there

01:53:51every day.

01:53:52The positions of stars and other objects would be constantly changing.

01:53:57In other words, say goodbye to normal navigation.

01:54:01The GPS system would likely be unreliable due to the strong gravitational forces and

01:54:06high radiation.

01:54:07So if you accidentally got lost in a glow-in-the-dark forest with some creepy animals, good luck!

01:54:15It's not all bad.

01:54:16The center is also home to molecular clouds.

01:54:20These are the regions of space where new stars are born.

01:54:24And the Milky Way in general has some pretty amazing sights to offer.

01:54:28For example, stunning nebulae like the Orion Nebula and the Eagle Nebula, which are visible

01:54:34with telescopes or even just a good pair of binoculars.

01:54:38So if earth were located in the center of the Milky Way, we would have a front row seat

01:54:43to some of the most spectacular cosmic events.

01:54:47Wouldn't that be awesome?

01:54:49Overall, if earth were located in the center of the Milky Way, it would be a very different

01:54:54place.

01:54:56Of course, we all understand that our planet wouldn't have survived such a change.

01:55:00But it's still pretty interesting to imagine how our life would flow if we were there.

01:55:06And judging by what we just discussed, it wouldn't be pretty.

01:55:10So let's treasure and appreciate our small, quiet solar system.

01:55:14This is Neptune.

01:55:15The next stop is Pluto.

01:55:18Stand clear of the closing doors, please.

01:55:21One day, with top-notch future technologies, one stop from Neptune to Pluto won't seem

01:55:26much further than Times Square from Bryant Park today.

01:55:29There are huge ice mountains on Pluto, valleys that go further than your eyes can see, 160-mile

01:55:35large craters, almost as big as the largest one on earth, and no life.

01:55:41The reasons are obvious.

01:55:42The long distance between Pluto and the sun guarantees freezing temperatures on that dwarf

01:55:47planet.

01:55:48It also ensures a trip of a few billion miles.

01:55:51Plus, it's smaller than the moon, so it would get crowded very soon if people started dwelling

01:55:57there.

01:55:58Still, there's one reason which makes life there not that far-fetched.

01:56:02The sun has a lifespan and cycles within it.

01:56:05Our solar system used to be nothing but a cloud of gas and dust.

01:56:08As a result of a gravitational collapse at the center of this cloud, the gas and dust

01:56:13started gathering in specific, denser places.

01:56:17These pulled more and more matter as time went on, and something called conservation

01:56:21momentum made the mass start rotating and heating up because of immense pressure.

01:56:27Later, there appeared a disk similar to what Saturn has, but it was made of entirely different

01:56:33And right in the center, there was the ball that eventually became the sun.

01:56:38A protostar is a young star that's still gathering its mass, and that's exactly what the sun

01:56:43was before the temperatures and pressures inside of it lighted up its core.

01:56:48Millions of years later, it became the sun we see every day.

01:56:52But it won't stay this way forever.

01:56:54It will heat up even more and eventually get bigger and denser, turning into a red giant.

01:57:00That may one day get big enough to swallow up Venus and Mercury.

01:57:04Chances are, it might swallow even planet Earth.

01:57:08Even if it doesn't devour our planet, the sun might get close enough to touch us.

01:57:12Well, if this happened, life on Earth wouldn't be possible.

01:57:16But then, in just a few minutes, the sun loses about 40% of its mass and shrinks about 10

01:57:22times what it used to be.

01:57:24It's not as bright, and indeed, not as hot as it used to be.

01:57:28By this moment, Earth will have already been deserted.

01:57:31People might want to start traveling around space or settle down on another planet where

01:57:36life is sustainable, like the exoplanet Kepler-62f, which, by the way, is even bigger than Earth.

01:57:43While all of this was happening, Pluto was changing.

01:57:46Before, every resource was frozen inside of the dwarf planet.

01:57:51Water, gases like methane, carbon monoxide, you name it.

01:57:55But as the sun was reaching its peak luminosity, Pluto was slowly warming up and losing a lot

01:58:01of what it had to the vastness of space.

01:58:03At the same time, an atmosphere formed up.

01:58:06If the atmosphere gets thick enough, it would create favorable life conditions.

01:58:10Then, instead of spaceships, a tiny percentage of us would be able to set up colonies on

01:58:16the dwarf planet.

01:58:17The temperature is comfortable there, almost t-shirt weather.

01:58:21It even resembles Earth a tiny bit.

01:58:23Canyons filled with water, beautiful endless fields with trees, and lots of space to run

01:58:28around, and mineral water pockets on the ground, good enough to drink.

01:58:33Pluto's rotations are different than Earth's.

01:58:35An Earth day is 24 hours, and sometimes it still feels like it never ends.

01:58:40But on Pluto, a whole rotation around the sun takes 153 hours, because it's pretty far

01:58:46away from the sun.

01:58:47After several hours without sleep, we get tired, and our eyes get red.

01:58:52That means we'd have to take several naps throughout the day on Pluto.

01:58:56A year on Pluto equals 248 Earth years.

01:58:59Unless we come up with some sort of technology to get us to live that long, our entire lifespan

01:59:04would be less than half a year on the dwarf planet.

01:59:08So, houses on Pluto might need to be equipped with cryo-chambers.

01:59:12Whenever you feel like dreaming for a long time, you jump in it and wake up 50 Pluto

01:59:17days later.

01:59:19On the dwarf planet, there are also seas and beaches, so it's just like a tiny Earth, far

01:59:24away from the actual Earth.

01:59:27The food on Pluto could be tastier.

01:59:29We might find a way to make the ingredients more savory, and even try to grow them faster

01:59:33during the trip.

01:59:34You plant a carrot, and two days later, it's ready to be in your salad.

01:59:39There could also be new ingredients for our salads on Pluto.

01:59:42Maybe two-meter-tall mushrooms we've never seen before.

01:59:46The animals we would take with us on the trip would get released into their new home

01:59:49forever.

01:59:50And with time, they would evolve and adapt to their new environments.

01:59:54The law of the jungle could change a bit, too.

01:59:57Lions might not be kings anymore.

02:00:00Deer are.

02:00:01Their antlers are twice the size of what they used to be.

02:00:04But to be fair, so are the deer.

02:00:06Most of the animals that were already here used to live underwater.

02:00:10But with time, the amphibians started shifting to the surface, just like Earth at the beginning

02:00:15of life.

02:00:16Pluto could only be a temporary home, though.

02:00:18Once the Sun has finally reached its final phase, Pluto would get frozen and lifeless

02:00:23again.

02:00:24People, instead, would need to try to find a planet that stays in the Goldilocks zone

02:00:29of another galaxy.

02:00:30The Goldilocks zone is the exact proper distance from the star like the Sun, where the temperature

02:00:35is perfect for the water to stay liquid.

02:00:38It's the rule scientists search for when looking for other planets that can sustain life.

02:00:43We can try setting new colonies on one such planet.

02:00:46Or even try to set up our own artificial home.

02:00:48Not exactly a planet or a spaceship, but a combination of both.

02:00:52Something huge built right in space.

02:00:54Say, a wheel with gravity everywhere we go, so we don't fall off.

02:00:59It would float in space toward the new exoplanet, capable of fitting entire states in.

02:01:04This whole trip might happen just because the Sun first grew too much.

02:01:08And then, having reached the culmination of its life cycle, it would finally become a

02:01:12white dwarf.

02:01:14It's going to be a pretty long journey, and entire generations will be born here.

02:01:18You'll have a choice, sleep your way through the journey until humans finally reach their

02:01:22new exoplanet, or enjoy the trip in this fantastic spaceship.

02:01:27There's all you need on board.

02:01:28Malls bigger than those on Earth, large futuristic cities, even places to farm, fields with rich

02:01:34soil made artificially, and finally, after a long journey, the exoplanet.

02:01:40It's even somewhat better than Earth.

02:01:42The planet is giant and has more continents.

02:01:45The continent's center isn't as far from oceans, which means there aren't as many desert areas.

02:01:51Though the Sun of this planet is an orange dwarf, it's not as hot as our yellow dwarf

02:01:55Sun today.

02:01:56It's a bit smaller, but here's the kick.

02:01:59Orange dwarfs live somewhat longer.

02:02:01They remain stable for between 15 billion and 45 billion years.

02:02:06Despite that, this new planet is full of rainforests because the planet itself is warmer.

02:02:12It means more biodiversity and creatures we've never seen before.

02:02:16But even if nothing out there is suitable, we could try and terraform this planet instead.

02:02:21If we take Mars as an example, we could create a greenhouse effect by smashing ice-rich comets

02:02:27and releasing ammonia in them, making the planet warmer.

02:02:31We could also start planting trees.

02:02:33We'd probably need some Earth soil to do that, or we'd have to modify Mars' soil to

02:02:37be similar to ours.

02:02:39Sooner rather than later, the atmosphere would be close to the one we have on Earth.

02:02:43We'd be able to breathe, too, because of the trees.

02:02:47Then, we can melt Mars' polar ice caps and voila, water.

02:02:52The problem is the solar winds and sun explosions that might strip it of an atmosphere just

02:02:57as quickly as we can create one, if not faster.

02:03:01It has no magnetosphere either, which means it can't protect us from radiation.

02:03:06So long-term Mars wouldn't be a good choice.

02:03:10Maybe out there, in the vastness that is space, there is a perfect planet waiting for us.

02:03:16That's it for today!

02:03:17So hey, if you pacified your curiosity, then give the video a like and share it with your

02:03:22friends!

02:03:23Or if you want more, just click on these videos and stay on the Bright Side!

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