First Animal to Survive in Space + More Out-of-This-World Wonders
Guess what, space enthusiasts? The first animal to survive in space has officially joined the celestial ranks! Tiny water bears, also known as tardigrades, pulled off this extraterrestrial feat. These microscopic creatures are tough as nails, withstanding extreme conditions and even the vacuum of space. But that's not all – did you know there's a diamond planet out there? It's true! A planet named 55 Cancri e is twice the size of Earth and likely covered in diamonds.
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00:00 Hey, we landed on the Moon!
00:03 We sailed around the world!
00:05 Romeo met Juliet!
00:06 Hey, it's hard to imagine that there are creatures out there who saw it all happen!
00:12 Immortal animals!
00:14 Well, almost…
00:18 Glass sponges are weird little creatures that sit in one place for thousands of years.
00:23 From their favorite spot under the sea, they witnessed the first Europeans crossing over
00:28 to the Americas.
00:29 They can live up to 15,000 years!
00:32 And what's even cooler is that they can control their aging process – speed it up
00:36 or slow it down!
00:38 They have a glass-like exoskeleton for protection.
00:42 Lobsters can grow back a limb if they lose it, and they're basically immortal.
00:47 They produce an unlimited number of enzymes that keeps their DNA young forever.
00:52 And they just keep on growing.
00:54 That means they outgrow their own shells.
00:56 They have to shed their exoskeleton every now and then and upgrade to a bigger one.
01:01 The largest lobster ever caught was 44 pounds off the coast of Nova Scotia.
01:07 Scientists think this large lobster was around 100 years old.
01:11 It was around when Edison invented the phonograph.
01:15 This next creature is a mix between a jellyfish and a tree branch.
01:20 Each end of the hydra has a ringed foot, and it spends its days chilling by lakes and rivers.
01:26 Its tentacles grab onto tasty snacks that swim past it.
01:30 So what's the secret to its immortality?
01:32 That's something everyone wants to know!
01:35 The hydra has the ability to renew its stem cells.
01:39 Scientists have been trying to do that for years.
01:41 They can actually slow down their aging process.
01:46 These little sea creatures are Red Sea urchins.
01:48 They sit on seaweed in shallow waters and are immortal.
01:52 Well, we haven't been studying them long enough to know for sure, but scientists say
01:57 they only grow in size, not in age.
02:00 What?
02:01 Well, they sort of stay like little baby urchins, but grow in size.
02:05 Adult, baby urchin, okay.
02:07 These little babies can reach around 100 years old, even 200.
02:12 The slowest on the list?
02:13 The giant tortoise.
02:15 It can reach 200 years old.
02:17 And one of the oldest is Jonathan.
02:20 He's technically the oldest crawling land animal.
02:23 He was born in 1832 and lives it up on a remote island called St. Helena.
02:29 Jonathan's been through a lot.
02:31 He's seen the very first American skyscraper, the Eiffel Tower.
02:36 Oh yeah, he's also lived through every single World Series, starting when he was 71 years
02:42 old.
02:43 So he can't see too well and he's lost his sense of smell, but he's still going strong.
02:51 Back to the oceans and the Greenland shark.
02:54 It's been known to be the longest-living vertebrate and can live more than 400 years.
02:59 Swimming around for that long in the deep, dark, cold ocean means these sharks are tough.
03:05 They're able to withstand insane water pressure.
03:09 Sharks are one of the only creatures today that haven't been affected too much by evolution.
03:14 Many sharks have been around since the dinosaurs and haven't changed much.
03:18 Scientists found out that they grow around half an inch per year.
03:22 So with a little bit of quick math, they can easily find out the age of these tough sharks.
03:28 Imagine seeing a shark that's older than the USA!
03:32 This next creature is probably the most durable, indestructible, and cutest on the list.
03:38 It's called a tardigrade, but scientists nickname it "water bear" because I guess it looks like
03:44 one.
03:45 But it's not exactly bear-sized.
03:47 It has eight legs and hands with a strange little nose.
03:51 And these bizarre microscopic creatures are indestructible.
03:58 They're known to live in the most extreme places on the planet.
04:02 They're fine with temperatures as high as 300 and as low as -330.
04:08 Volcanoes, frozen desert nights…
04:11 They can even handle radiation and massive amounts of pressure in the deepest parts of
04:15 the ocean.
04:17 They can even survive the vacuum in space.
04:19 No tiny little spacesuit or anything.
04:22 That would be cute enough.
04:23 So far, they've survived 10 days on the outside of a spaceship, but they could probably do
04:29 longer.
04:31 Tardigrades might be able to outlive humans if there's some sort of worldwide catastrophe.
04:36 Biologic organisms in charge of the planet.
04:40 Wonder what that would look like.
04:41 Whether it's all the volcanoes erupting at once, or another ice age, or even another
04:47 pesky asteroid.
04:49 Tardigrades probably wouldn't even notice.
04:51 Scientists are studying them to see if they can help us with some next-level biotech.
04:57 Just for fun, here's the mayfly.
04:59 This poor little insect doesn't even make it past 24 hours on average.
05:04 Males and males can make it to a whopping 2 days old.
05:07 Talk about living in the moment!
05:09 These little flies grow in swarms and are known to have one of the shortest lifespans
05:14 of any creature.
05:15 But as a species, well, they've been around for hundreds of millions of years.
05:21 Jellyfish have discovered the Fountain of Youth, and surprise, surprise, it's been
05:25 inside them all along.
05:27 Not inspirational poster style, but literally, it's always been inside them.
05:33 Jellyfish are able to reverse their aging process whenever they want.
05:37 Imagine you're swimming along and then you think to yourself, "Gee, I kinda wanna be
05:41 8 again."
05:42 And poof, there you are.
05:44 Who wouldn't want to go back to being 8?
05:46 That's how jellyfish stay young and live stress-free.
05:50 These brainless and boneless creatures can turn the clock back any time they want as
05:55 long as no one bothers them.
05:57 They're super chill, just floating in whatever direction the current takes them.
06:01 Like a go with the flow?
06:04 This creature looks like something right out of a sci-fi movie, and you could say it has
06:09 sort of alien features.
06:11 The giant weeda outweighs a mouse and is considered one of the biggest insects out there.
06:17 You find these big bugs in New Zealand.
06:20 While jellyfish can reverse their aging process, some members of the weeda family can come
06:24 back to life.
06:26 Talk about superpowers!
06:28 If they get completely frozen, they start to make special proteins that stop their organs
06:32 from getting ruined.
06:34 After whatever amount of time they're frozen, they can be thawed out and brought back to
06:38 life like nothing ever happened.
06:41 In fact, the giant weeda has ears on its knees and in its front legs.
06:46 And because it can resurrect, it's also called the zombie bug.
06:52 Planaria are flatworms that are unique.
06:54 Apart from being practically immortal, they're the ultimate regeneration machines for lost
07:00 body parts.
07:01 If you take one of them and divide its body into 10 parts, you'll end up with 10 new
07:06 planaria.
07:07 You keep dividing them up, they'll keep multiplying, even though they're usually
07:11 less than an inch long.
07:14 Imagine if we could figure out how to do that.
07:17 Would that be a way for us to live forever?
07:19 Or would we end up with a totally crazy world with copies of everyone walking around?
07:25 How about the world's fastest relay team – 4 identical Usain Bolts?
07:30 Clams have been around for a really long time.
07:33 Scientists have discovered that they can live up to 400 years old!
07:37 These little shelled creatures are the ones that create those shiny little pearls everyone
07:41 loves.
07:42 A clam will go into action mode when a parasite gets inside.
07:46 The clam tries to cover the parasite with a bunch of special chemicals – the same
07:50 ones it uses to make the inside of its shell.
07:54 That's when the magic starts to happen.
07:56 When these chemicals harden up, they make a shiny, glossy pearl.
08:00 The more chemicals, the bigger the pearl.
08:04 This long, slippery-looking creature lives deep in the caves of Europe.
08:08 Olm can live up to be 100 years old!
08:11 It spends its days hunting for little insects, snails, and crabs with its tiny front arms
08:17 and wriggling, snake-like body.
08:19 Its skin is so pale that some locals even call it the "human fish."
08:24 Hey wait a minute!
08:26 The olm is almost blind, but it can still detect light – it just mostly does it through
08:31 its skin.
08:33 Like other blind animals, it has a supercharged sense of hearing and smell.
08:37 It gets its distinct look from those little red gills around its neck.
08:43 Hey MythBusters!
08:44 Today we're debunking some classic space myths!
08:47 Hop on the next space shuttle and let's get to the bottom of these tales once and
08:51 for all!
08:54 Picture this – you're floating weightlessly in space, sipping on a cup of delicious hot
08:59 chocolate when a peculiar thought pops into your head.
09:03 Can you scream in outer space?
09:05 And if yes, would anyone hear that scream?
09:08 If you've watched the movie Alien, then you know the answer to this one.
09:15 You can't hear sounds in outer space.
09:17 It's not that sounds don't exist, it's just that you can't hear them.
09:22 There's no one better to clarify this myth than Chris Hadfield.
09:26 He's been on a couple of spacewalks during his life as an astronaut.
09:31 And once you're out there in the darkness of space, you can't hear anything.
09:40 But hey, just around the corner is a massive ball of explosion, aka the sun.
09:46 We just can't hear the explosions happening because there's no medium for sound to travel
09:50 through.
09:51 It would be quite uncomfortable for an astronaut though if they could hear all the noises going
09:55 on in outer space.
09:59 Now imagine you're zipping through space, feeling like a futuristic superhero, when
10:03 a shooting star passes by your side.
10:06 But wait, is it really a star?
10:08 Unfortunately, shooting stars are not stars at all.
10:12 They are small space rocks known as meteoroids, entering Earth's atmosphere and creating a
10:18 stunning light show.
10:20 Oh, and since we're debunking myths, let's head straight for another one.
10:26 You've probably heard that meteors only crash into Earth on extremely rare occasions, like
10:31 once every dinosaur extinguishing apocalypse.
10:35 That's not true.
10:37 Scientists estimate that about 48 tons of meteoritic material fall on Earth each day.
10:43 But almost all of this material is vaporized in Earth's atmosphere.
10:47 The bright trail we see in the night sky is what we popularly call a shooting star.
10:52 Next time you make a wish upon a shooting star, remember you're actually hoping on a
10:56 tiny piece of space debris.
10:59 It's not so romantic after all!
11:03 Can we or can we not fly into the stratosphere on air balloons?
11:08 Apparently, we can!
11:10 The Earth's stratosphere starts relatively close to the ground, about 7 or 8 miles up
11:14 from the Earth's surface, but it continues a long way up.
11:19 If you were to fly yourself all the way into the stratosphere with some type of air balloon,
11:24 just make sure you have really good equipment at hand.
11:27 You'll need a special suit and some breathing devices because air starts to get pretty thin
11:32 the higher you get.
11:34 Of course, if you do go all the way up, you need to get a picture of the Earth's curvature.
11:39 So take a chest harness with you where you can put a special camera or something like
11:43 that.
11:44 And how about you live stream the whole thing?
11:47 That would be a first!
11:50 Imagine it's been 102 days since you left Earth.
11:53 You've adapted well to life in outer space, but something weird is happening to your body.
11:59 You're getting taller!
12:01 How is that even possible?
12:03 Don't stress about it, it's completely normal!
12:06 The truth of the matter is, you're not getting taller.
12:09 This is what happens to your body when it's not under the effect of gravity.
12:13 Your body has natural space between vertebrae and joints.
12:17 On Earth, this space is almost completely squeezed due to the force of gravity.
12:22 But in space, your body gets some time off of the pushing force of gravity and begins
12:27 to stretch more and more.
12:30 So yes, astronauts can grow up to 3% taller when they're on long missions.
12:35 And here's a curiosity, NASA has that all covered when they're tailor-making spacesuits
12:39 of course.
12:41 This way, astronauts will always have extra space in their suits.
12:45 Once astronauts are back on Earth, the anti-gravity effect will wear off.
12:49 So maybe they'll spend a few days wearing capri pants before it fits perfectly on their
12:53 bodies again!
12:56 Never have I ever pictured an airplane door bursting open mid-flight and a bunch of passengers
13:01 being sucked into the atmosphere like flying feathers!
13:04 Well, I'm betting most of you have had similar thoughts when getting inside a plane.
13:10 Now imagine if this were to happen in outer space.
13:13 Common knowledge says that if an astronaut is sucked out of an airlock, this person would
13:17 be burnt to a crisp!
13:19 Brace yourselves, because this is not only true, but the reality of it is way worse!
13:25 According to astronaut Chris Hadfield, this is what would happen.
13:29 The part of your body in the shade of the sun would experience temperatures of -418
13:34 degrees Fahrenheit, while the part of you getting sunlight would burn at around 480
13:40 degrees Fahrenheit.
13:42 Your lungs would collapse, and your blood would start to boil like tea water.
13:47 So you would burn, freeze, lose your ability to breathe, and boil!
13:53 Yikes!
13:54 How many times have you heard that astronauts have to work out every second of every day,
13:59 otherwise they'll pass out?
14:01 This is a complete myth!
14:04 Remember we talked about gravity earlier?
14:06 Due to the lack of gravity in outer space, our bodies don't have to do any heavy work.
14:11 Our torsos don't have to sustain the weight of our heads, and we don't have to make
14:16 any effort to move our legs because, essentially, there's no walking in outer space!
14:22 Now imagine living like that for 6 months, or even a year of your life!
14:28 Your muscles could turn into jello!
14:30 That's why astronauts work out.
14:32 They'll strap themselves and run on a treadmill, or they'll do some weightlifting in a special
14:37 machine.
14:39 This way their muscles won't feel the lack of gravity too much.
14:43 They do need to keep hydrated though!
14:46 You know what?
14:47 If I was an astronaut, I'd ask NASA if I could take my super soft water flask up into
14:53 space with me!
14:54 You've probably heard that space smells like burnt steak or barbecue sauce.
15:00 Now as much as this sounds absurd, this myth is more true than it is false!
15:06 Astronauts obviously can't smell space when they're in it because they can't take off
15:10 their helmets.
15:11 They usually smell it once a space vehicle docks and they open up a hatch.
15:16 Apparently, what causes this smell is the presence of hydrocarbons that float around
15:20 in space.
15:22 Who would have thought, huh?
15:24 Hey smart people, let me ask you a question.
15:27 Do you really think that if astronauts fly at the speed of light, they won't age a single
15:31 second?
15:32 I knew you'd say no!
15:35 Let's get a few things straight.
15:36 First of all, we haven't figured out how to operate vehicles at the speed of light.
15:41 This would require an immense amount of energy and we don't have the technology to do that.
15:47 Second, even if we managed to send a human inside a spacecraft that travelled at the
15:51 speed of light, this person would still age.
15:55 They would age differently than the people who remained on Earth, that's a fact, but
15:59 they would still age.
16:01 Do you lot really think there's such a thing as immortality?
16:04 Nah!
16:06 If you've seen the first Avatar, then you certainly remember that humans only managed
16:09 to get to Pandora because they travelled in cryosleep.
16:13 In other words, they froze their bodies, put them in a cryo bed and travelled for years
16:18 without aging.
16:19 Yes, this sounds amazing, but we still don't have the technology to do that.
16:24 Our bodies are mainly made out of water, right?
16:27 And when you freeze water, it expands.
16:30 That's why you should never leave soda cans unattended in your freezer.
16:34 Right now, if we froze a person's body, the water inside of it would expand, harming tissues
16:39 and organs.
16:41 So no, we can't cryosleep our way into interstellar travel.
16:45 Not yet at least.
16:48 Here's a crazy thought.
16:49 What would happen if an astronaut took a drone with him on one of their spacewalks?
16:54 Unless it's a NASA designed drone, maybe the thing would freeze and burn like humans would
16:59 if they went into space without a suit.
17:01 But hey, a person can dream, can't they?
17:05 You've been training for this for years.
17:11 You know you're ready.
17:14 You're standing on the door's threshold.
17:16 You take a deep breath and bravely open it.
17:20 You jump outside the International Space Station and into the vastness of space.
17:25 "Ah, this never gets old," you say on the transmitter device.
17:31 You feel like a feather whenever moving through space.
17:34 Except for the suit, of course.
17:38 It's true what that guy told you one day.
17:40 Astronaut suits limit your body's movement by 20%.
17:44 For you, that means you've got a 20% higher chance of being clumsy in outer space, which
17:49 is never good odds.
17:51 There's not a lot of room for error during a spacewalk.
17:54 You finally get to the docking port.
17:57 You look around and see the part of the station that needs fixing.
18:01 This is where other space shuttles dock when they come in from Earth or other planets.
18:06 About a week ago, a shuttle coming from Jupiter miscalculated the landing and broke a piece
18:11 of the port.
18:13 You've attached the new shield to your suit's belt.
18:15 Now all you've got to do is screw it on the station.
18:19 You've spent hours training underwater to do this.
18:22 You wore a heavy, hot, uncomfortable suit inside a pool in order to get the training
18:26 you needed.
18:28 "Incoming!" Sarah shouts on the transmitter.
18:32 You don't even have time to ask what, as an absurdly fast storm of space debris catches
18:36 you off guard.
18:38 It shakes everything around you.
18:39 You try to hold on tight to the strap that's keeping you safe, but oh no!
18:43 A piece of debris just hit your helmet shield.
18:45 "Come in, Bob.
18:47 Are you okay?"
18:48 Sarah asks you through the radio.
18:50 You got a bit shocked by the impact, but everything seems fine.
18:54 The meteorites are finally gone, so you can focus on your task now.
18:58 You pull the rope that's connecting the new docking shield closer to your body, but the
19:02 other part of the rope has nothing on it.
19:04 Zip.
19:05 Nada.
19:06 "Oh my," you think to yourself.
19:08 "Hmm, come in, Sarah.
19:09 We have a lost shield.
19:10 I repeat, we have a lost shield."
19:14 This is a pretty serious situation, and you are aware of it.
19:18 Anything that falls into space can go into a collision route with the International Space
19:21 Station or with other space vehicles.
19:24 You try to remember your training, but your mind goes blank.
19:28 This is worse than that one time you broke your girlfriend's favorite ceramic jar.
19:32 Sarah, the other astronaut who's with you on the ship, is shouting words on the transmitter.
19:37 "Oh no, Bob.
19:38 Tell me you didn't do this.
19:40 This is a total catastrophe.
19:41 I'm coming outside."
19:44 You spot the shield under the ISS.
19:46 It's the size of a medium-sized car door, and it's moving quite fast.
19:51 Here's what can happen in this scenario.
19:53 The shield could head back down to Earth and break into the atmosphere.
19:57 It would probably catch fire and disintegrate on the way down, but anyways, it would make
20:01 NASA and you look pretty bad.
20:03 The other option is the car door-sized shield gains momentum, and it orbits all the way
20:09 to hit the ISS, and you for that matter, or some satellite that happens to be in a similar
20:14 orbit.
20:16 Here's the thing.
20:17 If you ever thought that space was an infinite void, you got that part wrong.
20:22 Since different countries started to build equipment strong enough to travel in space,
20:25 space has been more crowded than ever.
20:27 Not with people, but with satellites, asteroids, and space debris.
20:32 You were surprised when you learned that Earth receives meteorite showers every single day,
20:36 but they're so small that no one on the surface of the planet notices it.
20:39 They usually turn to ashes before hitting the ground, but that's not all.
20:45 What just happened to you on this mission has happened on several other missions before.
20:49 Astronauts keep losing stuff in outer space.
20:52 So much so that NASA had to create a division to track down and monitor the orbit of all
20:56 debris that is just floating carelessly around.
21:00 You couldn't believe it when someone told you that there are over 23,000 softball-sized
21:04 pieces of debris roaming around in space, and if we're talking about smaller objects,
21:09 then that number goes up to half a million.
21:12 As you were about to unstrap yourself and dangerously venture through outer space without
21:16 any protection, you notice Sarah has beat you to it.
21:20 You can't let her do this alone, so you decide to tag along.
21:24 FYI, this is against every NASA handbook and training you ever received in your life.
21:30 But you think, "If this works in sci-fi movies, it must work for us."
21:35 Even though we all know that's very far from the truth.
21:38 Sarah is close to the debris shield, but her body weight makes her orbit in a completely
21:42 different direction.
21:44 "Okay," you think to yourself.
21:46 "This is your turn to shine and be a hero."
21:49 You try moving your arms like you would do underwater, but there's no friction in space.
21:54 Duh.
21:55 You can't butterfly swim your way to rescue the rogue equipment.
21:58 You try to contact Sarah, but she doesn't come in.
22:01 I guess you're on your own now.
22:05 For some reason, you start to orbit in a similar route as the floating car door shield.
22:09 It must be the amount of stuff you've got strapped onto yourself.
22:12 Or maybe it was the breakfast burrito you had that morning.
22:15 You feel like you're George Clooney in the movie Gravity.
22:18 No, better yet, you feel like Obi-Wan Kenobi.
22:22 Yes, you're feeling as strong and powerful as a Jedi right now.
22:26 You keep your hands stretched before your body, hoping you'll gently collide with the
22:30 space debris.
22:31 And three, two, one, and the landing was successful.
22:34 Joking, but yes, you managed to dock onto the debris.
22:37 Hooray.
22:38 Now what, you think?
22:41 Guess you needed to have gone through that plan of yours a little bit more, huh?
22:44 You still have no way of steering the debris.
22:47 And now, you have no way to contact mission control and tell them the object, and yourself,
22:53 are en route to somewhere.
22:56 Don't get scared.
22:57 You didn't come this far to get scared.
22:59 What's the best thing you can do?
23:01 First, take a mental picture of the Earth.
23:04 It never disappoints, from up here.
23:06 Then, you try to play out the possible scenarios that could happen in the situation ship you're
23:10 in.
23:12 Your normal body weight would not be enough to get you out of Earth's orbit.
23:16 In the hypothetical scenario in which this did happen, you'd probably be vacuumed into
23:20 Venus's orbit, and spend a quite unpleasant period of your life around immense heat.
23:25 Even though in Greek mythology, Venus represents love, there is nothing lovely about orbiting
23:30 close to this planet, and you know this.
23:33 If you got too close, your spacesuit would never be able to take on the heat.
23:37 It's only made to sustain temperatures of around 250 degrees Fahrenheit tops, and Venus's
23:42 atmosphere can heat up to 700 degrees Fahrenheit.
23:46 But honestly, the worst case scenario is much simpler than that.
23:50 Your spacesuit could decide to drown your ears, nose, and mouth in water.
23:54 Yup, this has happened on spacewalks before yours.
23:58 You see, in order to keep your spacesuit chill and cool, the suit relies on a gallon's worth
24:03 of water that makes up for a cooling system.
24:07 This system, which is supposed to send recycled air into the back of your helmet, does leak
24:11 sometimes.
24:12 And since you're stranded in the middle of the big nowhere, you'd have only that nowhere
24:16 to run.
24:17 But wait, what's that popping up on the horizon?
24:21 It's a modular space shuttle.
24:24 You try shouting, but nobody can hear you outside your helmet.
24:27 You wave with your hands, but it's coming straight at you.
24:32 "Finally, it took longer than I wished to find you," Sarah said.
24:37 Apparently, she made it back to the space station just in time to catch you before you
24:41 went definitely rogue.
24:42 "Guess I'll be losing some astronaut points for this little misadventure, huh?" you say.
24:48 And yes, you definitely will.
24:53 Astronomers have been asking one question for decades.
24:56 Is space really as black as we think it is?
24:58 Well, NASA's New Horizons space mission might have just given us the answer.
25:04 After exploring Pluto, the spacecraft kept going and is now billions of miles away from
25:08 Earth.
25:09 This means it's far from all the light pollution we get from sources like the sun and dust
25:13 particles around our planet.
25:16 Scientists used the spacecraft's simple camera to take images of what looked like incredibly
25:20 boring blank space, free of bright stars or anything else that could scatter light back
25:25 into the camera.
25:26 They then processed these images to remove all known sources of visible light.
25:31 Once they'd removed the light from stars, plus scattered light from the Milky Way, they
25:35 were left with light coming in from beyond our own galaxy.
25:39 But here's the surprising part.
25:42 They found that there was still plenty of unexplained light.
25:44 In fact, it was about equal to all the light coming in from the known galaxies.
25:49 That means there's just as much light outside of galaxies as inside them.
25:53 So where does all this light come from?
25:55 Well, it could be coming from sources we haven't yet discovered, like small, faint dwarf galaxies
26:00 or unknown phenomena out in the universe.
26:03 Or it could be associated with dark matter, which is still a mystery to scientists.
26:08 With this groundbreaking research, we can say that space isn't as dark as we know it.
26:12 What if we take all the light from the stars and galaxies out there and throw in some gas
26:16 and dust clouds?
26:18 What color do we get?
26:20 Beige.
26:21 This leads us to another question.
26:23 Do we still need the sun if our space is colorful?
26:26 And the short answer is, yes, we do.
26:29 The colors of space are a result of the interactions of light with different celestial objects,
26:34 such as stars, galaxies, and gas clouds.
26:37 While these colors are fascinating to observe, they do not provide the energy life on Earth
26:41 needs to survive.
26:43 There you go.
26:44 Don't expect to see the color of the sky in space.
27:15 It happens when sunlight goes through the atmosphere.
27:17 But if you were on the moon or somewhere else in space, there would be no atmosphere to
27:21 spread this light around.
27:23 That's why the sky there would always appear black.
27:27 But it doesn't mean less bright out there.
27:30 If you were looking out the window of the space station, you'd see just as much direct
27:34 sunlight as you would gazing out of your apartment window during a cloudless day.
27:38 Maybe even more.
27:40 When taking a picture on a sunny day, you'll probably use a short exposure, together with
27:45 the narrow aperture setting on your camera.
27:48 This way, just a short burst of light will get in.
27:51 That's similar to how our pupils contract in sunlight so that they don't have to deal
27:54 with too much light.
27:56 And since it's just as bright up there in space, the process is the same when you take
28:00 pictures of sunlit objects there.
28:03 Using short exposure, you can get good, bright pictures of Earth or the surface of the moon.
28:08 But it also means there will be no stars in the picture.
28:12 Even up there, stars are relatively dim.
28:15 They don't emit enough light to show up in photos taken with such settings.
28:20 Our home planet has a blue sky that slowly transforms into a beautiful orange-red palette
28:25 at dusk and dawn.
28:27 But if you ever get a chance to watch a sunset on Mars, you should expect the opposite, an
28:32 orange-brown daytime sky that gets a bluish tint at sunset.
28:37 First of all, Mars is farther away from the sun than our planet.
28:40 So when you're looking at the sun from the Martian surface, of course it looks fainter
28:45 and smaller.
28:46 And not just that, the sun observed from Mars is just a bluish-white dot surrounded by a
28:51 blue halo.
28:52 The thin atmosphere of the red planet contains large dust particles.
28:56 They create an effect called "Mye Scattering".
28:59 It occurs when the diameter of particles in the atmosphere is almost the same as the wavelength
29:04 of the scattered light.
29:05 This effect filters out the red light from the sun's rays.
29:08 So only the blue light would reach your eyes on Mars.
29:14 How come Earth doesn't have rings?
29:16 All gas giants in our solar system, Jupiter, Saturn, Uranus, and Neptune have such rings,
29:22 whereas the rocky planets Mercury, Venus, Earth, and Mars don't.
29:27 There are two theories about how rings can appear around a planet.
29:31 They might be just some material left from the times when the planet was forming.
29:35 Or they may be the remains of a moon that got destroyed by a collision with some space
29:39 body or torn apart by the strong gravitational pull of its parent planet.
29:45 The gas giants formed in the outer regions of our solar system, while all the rocky planets
29:49 are in the inner part.
29:51 So maybe the inner planets were more protected from potential collisions that could have
29:55 formed their rings.
29:57 There are also more moons in the outer regions of our solar system, which could be another
30:01 reason why the planets there have rings.
30:04 Also, bigger planets have stronger gravity.
30:07 It means that they can keep their rings stable after they form.
30:12 Some experts believe Earth used to have a ring system a long time ago.
30:16 A Mars-sized object might have collided with our home planet, which probably created a
30:20 dense ring of debris around it.
30:23 Some scientists think that this debris formed not a ring but what we know today as the moon.
30:30 There is probably a giant planet lurking at the edge of the solar system, far beyond Neptune.
30:36 Scientists call this mysterious hypothetical world Planet 9.
30:40 If it does exist, it's probably similar to Uranus or Neptune and 10 times more massive
30:46 than our home planet.
30:47 It's likely to circle around the Sun, but in the outer reaches of the solar system,
30:52 about 20 times farther than Neptune.
30:55 Another interesting theory says that Planet 9 could actually be a black hole the size
31:00 of a grapefruit that warps space in a similar way a large planet would.
31:06 Even though we once thought it was a rare substance in space, water exists all over
31:11 our solar system.
31:13 For example, you can often find it in asteroids and comets.
31:17 It's also in craters on the Moon and Mercury.
31:20 We still don't know if there's enough water to support potential human colonies if we
31:24 decide to move there, but some amount of water is definitely present there.
31:30 Mars has water at its poles too.
31:32 It's mostly hidden in the layers of ice and probably under the planet's dusty surface.
31:37 Europa, Jupiter's moon, has some water too.
31:41 This is the most likely candidate we know about to host life outside Earth.
31:45 There's probably a whole ocean of liquid water under its frozen surface.
31:50 It might actually contain twice as much water as all of Earth's oceans combined.
31:56 Neptune is unexpectedly warm, even though it's 30 times as far from the Sun as our
32:01 planet and receives less sunlight and heat.
32:04 But it still radiates way more heat than it gets.
32:07 It also has way more activity in its atmosphere than you'd suspect, especially if you compare
32:12 it to its neighbor, Uranus.
32:15 Both of these planets emit the same amount of heat, even though Uranus is much closer
32:19 to the Sun.
32:21 No one knows why.
32:22 Neptune has extremely strong winds that can reach a speed of up to 1,500 mph.
32:29 Can they produce this heat?
32:30 Or maybe it's because of the planet's core or its gravitational force?
32:36 There's a monster black hole hurtling through space at a speed of 5 million mph.
32:42 Scientists located it with the Hubble Space Telescope.
32:44 They believe it weighs as much as a billion suns.
32:48 It was supposed to stay put in the center of its home galaxy, but some gravitational
32:52 forces are pushing it around.
32:55 At one point, this black hole is going to break free from its galaxy and continue roaming
32:59 the universe.
33:00 Luckily, it's still 8 billion years away from us.
33:05 Solar storms are so powerful that they could leave us in complete darkness.
33:09 Back in July 2012, the strongest solar storm in over 150 years narrowly missed Earth.
33:17 Coronal Mass Ejections, or CMEs, are large bubbles of ionized gas.
33:23 They tore through our orbit back then.
33:25 If they had caught our planet in the crosshairs, we would have literally been in the firing
33:30 line.
33:31 We'd have faced solar matter hurtling towards Earth, damaging computers and causing power
33:35 outages that would have lasted for months.
33:38 A surprise solar storm hit us on June 25, 2022.
33:43 One photographer even managed to capture stunning bright auroras that flashed across the dawn
33:47 sky in Calgary, Canada and lasted for 5 minutes.
33:51 They were caused by the storm.
33:55 Vampire stars are a real thing.
33:57 They're part of a binary star, and they can literally drain the life out of the other
34:01 star in the system.
34:03 They do it to keep burning for a longer time.
34:05 It works like this.
34:07 A smaller star with a lower mass steals its sibling's hydrogen fuel to increase its
34:12 own mass.
34:13 This vampire star then becomes hotter.
34:16 Plus, its color changes to striking blue.
34:19 This way it looks much younger.
34:20 How sneaky!
34:23 The color of the universe is dubbed "Cosmic Latte."
34:27 The light coming from our galaxies and stars within them, as well as clouds of gas and
34:31 dust in the observable universe, have a specific color.
34:35 It's an ivory tint, pretty close to white.
34:39 The universe is beige because there are a bit more areas that produce green, yellow,
34:44 and red light than those that emit blue.
34:48 Did you know that humans are real space people?
34:52 You were born in space.
34:53 Heck, even I was born in space.
34:55 We were all born in space.
34:58 But for humans to be here on Earth, so many conditions have to be precisely correct that
35:03 it's highly improbable that we even exist.
35:06 But we do.
35:08 First, we, and any other space creatures who might be out there, have to live on a planet
35:13 orbiting a yellowish-white star, not a red star or a blue star.
35:19 Not a blue star, because they burn out too quickly.
35:22 In a few million years, there wouldn't be time for evolution to do its relatively slow
35:26 magic and produce intelligent beings.
35:29 Blue stars also tend to swell up and turn red when they collapse and explode.
35:35 That makes it highly unlikely that any civilization could prosper near a blue star.
35:41 Red stars, which are by far the most numerous kind of stars, don't seem like good prospects
35:46 for intelligent civilizations to orbit around either.
35:49 Red stars are so cold and so dim that a planet that could grow a civilization must orbit
35:55 very closely to the red star, which would expose the planet to intense, deadly X-ray
36:00 radiation.
36:01 So, though red stars are the most numerous and appear to have many planets orbiting them,
36:06 red stars are a no-go for hosting intelligent, civilized life like our own.
36:12 That leaves the yellowish stars, about 10% of all stars.
36:17 However, an important fact must be met before considering the possibility of intelligent
36:22 life living around a yellowish star.
36:24 That fact is that the yellow star must be a third-generation star.
36:29 Only third-generation stars will contain sufficient chemical diversity to sustain advanced life
36:34 forms.
36:35 Each time a star explodes, heavier, more complicated elements are created.
36:40 The explosion expelled these elements and eventually found their way into a nebula.
36:45 Gravity within the nebula will gradually form the next generation of stars, and so on.
36:51 Our bodies need calcium for our skeletons and teeth.
36:54 Our brains need zinc to help create the electrochemical signals that make us move, feel, and think.
36:59 Our blood needs iron.
37:02 Therefore, our bodies need to have formed around a third-generation star, and a yellow
37:07 one.
37:08 Amazingly, Earth has all the different elements in the universe, all 94 naturally occurring
37:13 ones, from hydrogen to plutonium.
37:15 Maybe that's why we're here, and we have to thank our third-generation yellow dwarf sun
37:20 for that.
37:21 Why yellow?
37:22 Because yellow stars burn very steadily by nuclear fusion, without significantly changing
37:27 brightness over billions of years.
37:30 If our sun became just 6% brighter or dimmer, Earth would become too hot or too cold to
37:36 sustain civilized life.
37:38 Fortunately, Earth is in the "habitable zone" around the sun.
37:42 The habitable zone is where liquid water can exist on a planet.
37:46 But that brings us to the second condition necessary for intelligent life to live in
37:50 space, the planet itself.
37:54 Recent studies with the Kepler telescope have shown that one quarter of all yellow dwarf
37:58 stars may contain Earth-like planets in the habitable zone around yellow dwarf stars.
38:04 That figure is somewhat debatable.
38:06 It might be as few as one out of every 33 yellow dwarf stars, but that's still a lot
38:11 of planets orbiting yellow stars in habitable zones.
38:15 So let's consider the second essential component for intelligent life in space, the planet
38:19 itself.
38:21 The planet that would bear intelligent civilization must have many particular characteristics
38:25 that aren't easy to come by individually, and even more rare to find in combination.
38:31 Most importantly, the planet must have protection against the star it's orbiting.
38:36 Because stars shine by nuclear fusion in their cores, gas in the outer shell of the sun,
38:41 called the corona, gets blown off into space in what's called the solar wind.
38:46 More United States satellites take constant readings of the force of the solar wind, which
38:51 is mainly electrified, ionized, hydrogen nuclei, along with a smattering of atomic nuclei
38:57 from the many other elements found in the sun.
39:00 It's not the atmosphere that protects Earth, it's the magnetosphere that stops, or deflects,
39:06 the dangerous solar wind, causing aurorae when the solar wind is attracted to Earth's
39:10 magnetic poles and electrifies the air of the upper atmosphere like a fluorescent bulb.
39:16 Without a magnetosphere surrounding it, any planet, even those in habitable zones, would
39:21 be toasted by a constant rain of ionized hydrogen nuclei from its star.
39:26 A planet with life on it must have a magnetosphere strong enough to deflect the solar wind.
39:32 Not every planet in our solar system has a magnetosphere.
39:35 The gas giant planets, Jupiter, Saturn, Uranus, and Neptune, have magnetospheres, but gas
39:41 planets cannot have civilizations.
39:43 Of the solid worlds, only Earth and Mercury have magnetospheres, and Mercury is too weak
39:49 to stop the solar wind because of its closeness to the sun.
39:52 Another protective shield that keeps the Earth safe from the sun is its atmosphere.
39:57 The atmosphere is about 300 miles thick, with most of it concentrated within just 10 miles
40:02 of the Earth's surface.
40:04 The atmosphere protects life on Earth from both the sun's ultraviolet (UV) radiation
40:09 and x-rays.
40:11 The gas, ozone, which is three oxygen atoms bound into a large gas molecule in the upper
40:16 atmosphere, blocks most of the sun's UV radiation from reaching the ground.
40:21 The planet Mars, whose atmosphere is 1,000 times thinner than the Earth's, has no ozone,
40:26 and the sun's ultraviolet emissions have totally irradiated its surface.
40:30 A planet must be able to stop the UV radiation from its star, so the specific composition
40:36 of the atmosphere is critical for any planet to have an intelligent civilization.
40:40 We've got it, but it is a rare and precarious mix.
40:44 The planet must have some part of its surface solid to walk and work on.
40:49 The planet must have a crust.
40:51 It's pure science fiction to consider underwater civilizations or floating civilizations in
40:56 the atmospheres of other planets.
40:58 A planet's crust must have tectonic plates that move.
41:01 This movement of tectonic plates creates the subduction of the crust.
41:06 Subduction is when one tectonic plate slides under or over another, bringing the fresh
41:11 matter to the surface.
41:13 This renewal of the chemical properties of the planet prevents chemical equilibrium,
41:18 where nothing is reactive.
41:20 Earthquakes and volcanoes also contribute to the process of geochemical renewal.
41:24 That's right, earthquakes and volcanoes are good!
41:28 Subduction of tectonic plates, then, is another planetary essential for life.
41:33 Mars doesn't have tectonic plate activity.
41:35 And neither does Venus nor Mercury.
41:37 Mercury is one big tectonic plate, but there's no ongoing plate activity other than slight
41:43 shrinkage.
41:44 One big reason these planets have no life is that there's no geochemical reactivity
41:49 because there's no tectonic subduction.
41:51 And that brings us to the Moon.
41:53 Yes, the Moon.
41:55 To say that the Moon keeps us alive may seem like a stretch, but the contribution of the
42:00 Moon to life on Earth is essential.
42:02 First, the gravity of the Moon as it moves through space with the Earth not only makes
42:07 the ocean tides ebb and flow, it also helps the rotation of the Earth to churn or stir
42:12 the magma inside the Earth.
42:15 The motion of the magma inside the Earth, with its high metallic content, contributes
42:20 to the creation of the Earth's magnetosphere.
42:22 So the Moon keeps us safe in space by helping Earth become a geodynamo and creating our
42:29 magnetism.
42:30 The Moon is the largest Moon in the solar system compared to the size of the planet
42:34 it orbits, essentially its primary.
42:37 Many people consider the Earth-Moon system to be a double planet, but that's another
42:42 issue.
42:43 Another thing the Moon does that keeps life safe on Earth is to hold the Earth steady.
42:48 Because the Moon is gravitationally locked to the Earth, the Moon acts much like a balance
42:53 pole does for a tightrope walker.
42:55 Therefore, the Earth doesn't wobble very much compared to other planets.
42:59 This wobble is called libration.
43:02 If the Earth wobbled as much as Mars or Saturn, not only would our weather become chaotic,
43:07 but farming might have been impossible.
43:10 These rare or unique astronomical circumstances work together to make Earth habitable for
43:15 humanity.
43:16 Many other factors are not astronomical, such as evolutionary, biological, and chemical
43:22 factors required for life to exist on Earth.
43:25 The probabilities, or improbabilities, are multiplying.
43:29 All in all together, we are very, very lucky to be here.
43:33 In fact, we're so lucky that we may have hit the jackpot!
43:37 Considering all the possibilities, it's doubtful that anywhere else in the Universe
43:42 is as fortunate as Earth.