Nebulas are the strange structures of cosmic gas and dust where stars are born and die, and new discoveries reveal the secrets of these mysterious places.
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LearningTranscript
00:00all across our galaxy stunning clouds of gas and dust nebulas they contain secrets of the cosmic
00:11circle of life the birth and death of stars planets and us these things are really cradles
00:20of creation you are intimately related to the nebulas you are a nebula come alive the story
00:29of how our solar system formed starts with a nebula if you want to build a solar system you're going to
00:36need a nebula look around you everything you see everywhere was once inside of a nebula
00:42now scientists are pulling back the veil opening our eyes to the true expanse of our universe
00:53solving the riddles of these engines of creation
00:58there are mysteries waiting inside that we haven't even guessed at yet
01:03the milky way a spiral galaxy full of regions of gas and dust called nebulas and everyone has their
01:29favorite i really like the horse head nebula it just looks awesome the cat's eye nebula has always
01:35been really captivating to me my favorite nebula is the orion nebula the orion nebula is perhaps the
01:43best place to understand the evolution of stars and it's right here in our own backyard the orion
01:51nebula is maybe one of the most famous nebulas because you can go outside at night and see it
01:56with your own eyes humans have been observing this fuzzy patch of sky for centuries the maya of
02:03central america called it the fire of creation the maya were more right than they knew almost every
02:13part of the life cycle of a star you can see in a nebula we can't understand the life cycle of stars
02:21without understanding the life cycle of nebulas they are intertwined orion has it all from massive
02:29stars on the brink of death to newborn stars swaddled in gas you see the intricate wisps of material the
02:38thin veils enveloping newborn stars pillars colliding into each other you see stars plowing through clouds of
02:48gas you see this frenzied hive of activity operating right before our eyes in 2018 using new data nasa creates a
03:02groundbreaking 3d visualization of orion's interior for the first time in history we have the right tools to
03:10actually explore the hearts of these nebulas it was already beautiful to begin with but now we have
03:18even more vivid images to really appreciate how great of a structure this is at orion's heart lies
03:26a cluster of young stars together they blast out charged particles and solar winds blowing open a gap at
03:35the center creating a window inside we actually see the structures in the volume we can actually see
03:43the processes happening right before our eyes the clusters intense starlight energizes the surrounding
03:51gas causing it to glow pink and blue the pinks come from light emitted from hydrogen atoms in the nebula
04:00glowing like the gas in a neon tube the blues tend to come from the light from the hot new stars reflected
04:07off of dust particles these hot new stars illuminate the orion nebula but they were actually born in the dark
04:17one particular type of nebula is a dark nebula and basically that's when the concentration of dust is a lot
04:25greater dense clouds of dust block out visible light from the stars behind creating shadowy shapes like
04:37the horse head nebula this nebula is so large and dense it has enough mass to make about 30 stars the size of
04:45our Sun and now astronomers can peer inside only recently have we been able to start doing this thanks
04:55to detectors that can see light in the infrared the infrared allows us to sort of see through the dust of a
05:02nebula and see what's going on deep in its heart humans can't see infrared light but we can feel it as heat
05:12infrared detectors tell us these dark star forming clouds are cold hundreds of degrees Fahrenheit below
05:21freezing but deep inside our hotspots if you look at with infrared you see ah the signature of incredible
05:36densities and incredible temperatures the signs that a new star is being born a knot of matter comes
05:45together under the force of gravity as it grows so does the gravity it pulls in more gas growing bigger
05:53and bigger that gets very massive very dense and very hot eventually it gets high enough pressure and
06:03temperature in the center of that object that you ignite fusion a star is born
06:10one of the hundreds of billions that make up our galaxy the latest in a stellar production line going
06:23all the way back to the dawn of time and the very first nebula if we want to unravel the history of the
06:31milky way we want to start in the beginning and that's the big bang
06:3413.8 billion years ago the universe sparks into life at first it's pure energy
06:50but over 300,000 years that energy cools into hydrogen and helium gas back then
07:00the entire universe was one enormous cloud the essential ingredients of our universe spread
07:09as the universe expanded and so the universe started as one giant nebula over time the primordial nebula
07:18starts to collapse and fragment into smaller clumps these regions become so dense they collapse into discs
07:27with super hot balls of gas in their cores
07:29the first stars ignite they start out as nearly pure hydrogen but as they age they make other heavier elements
07:45they make other heavier elements stars forge new elements that's what they do the very definition
07:53of a star is in its core it's fusing hydrogen atoms into helium and releasing energy but many of those first
08:01simple stars were massive and massive stars don't live for long they burned through their supply
08:09of hydrogen incredibly rapidly and they burn themselves out and they died after a few million years
08:16they go out with a bang
08:25an explosion that releases more complex elements back into the primordial nebula
08:32after that first generation of stars started to form there was this huge burst of new elements
08:39that formed and that were dispersed throughout the universe to be able to form that next generation
08:43of stars as the second generation of stars lives and dies it adds even more ingredients to the cosmic mix
08:53the next generation of stars fused more elements exploded died spread the material new generation of nebula
09:00new generation of stars each generation having more and more elements in the periodic table than the last
09:08first generation of stars and around 300 million years after the big bang our galaxy the milky way takes shape
09:21galaxies like the milky way formed out of essentially a proto galactic nebula some gigantic gas cloud
09:27that collapsed down and formed our galaxy
09:29there is a rich cosmic symphony playing back and forth between stars and nebulas and we
09:40now know that we are a part of that symphony
09:49eventually our element rich sun is born
09:52we think that our sun is a third generation star so it was actually a nebula a star a nebula a star a
10:03nebula before it became our sun it took around 10 billion years to create a cosmic mix of elements
10:12rich enough to build planets and life carbon hydrogen nitrogen oxygen phosphorus and sulfur these are the
10:22key ingredients to life as we understand it and those need to be made in stars these elements are
10:29created during the life of a star but it takes an incredibly violent process to liberate them into the cosmos
10:39an event that can be seen clear across the universe a supernova
10:52the most beautiful nebulas in our galaxy are born out of incredible violence the deaths of giant stars
11:14some of the most colorful nebulas in our galaxy are remnants of supernova explosions things like the crab
11:18nebula castiopeia a also the veil nebula those all happened when a giant star exploded violently
11:30the crab nebula was once a massive star with around 10 times the mass of the sun
11:36in its core that star crushed atoms together to form heavier elements a process that releases huge
11:50amounts of energy a massive star confused heavier elements and those heavier elements into even heavier
11:58elements until it gets to iron and when it gets to iron that's when things go bad really fast
12:04iron atoms are so big that fusing them takes up more energy than it produces the core starts to collapse
12:14on itself setting off a catastrophic explosion
12:23blasting elements out into space
12:25when a star goes supernova it violently rips itself apart and all of the material of the star can be
12:34spread across light years we call this rather obviously a supernova remnant nebula now you have a
12:41nebula filled with all of these interesting chemicals all of those are illuminated by the energy of the supernova
12:48explosion supernova remnant nebulas glow brightly in many different colors
12:56the colors in a nebula are kind of like a fingerprint or a dna test of the elements inside
13:05every atom has a shell a cloud of electrons that orbits around its nucleus and as those electrons
13:11change energy levels the frequencies of light associated with those energy changes
13:16are emitted into space and contribute to the broad spectrum of colors that we see
13:21so we can look at a distant nebula and we can say it's this much hydrogen this much helium a little
13:30bit of platinum oh we got a lot of oxygen in that one
13:33the colors of a nebula reveal the elements created during a star's life and death
13:44but a nebula's shape can reveal what happens after a star dies
13:48you would think that one exploding star would be pretty similar to every other one they would
13:53make the same sort of nebula and then you see the crab nebula with this beautifully complex shape
13:59all of these different arcs and worlds of gas and dust something must be shaping it from the inside
14:08within the crab nebula lurks a stellar corpse called a pulsar
14:14pulsars are a kind of neutron star a ball of super dense matter they're born from the death of massive stars
14:23this is the leftover core of the star that exploded this collapsed down and formed a very tiny ball of
14:30neutrons and a little bit of normal matter that's very very hot and has a very very strong magnetic field
14:39this pulsar is spinning at around 30 times a second
14:44blasting out beams of radiation that sweep through space like a frenzied cosmic lighthouse
14:50and the pulsar in the crab nebula doesn't just emit light it's also blasting out a wind of charged particles
15:02the gas cloud itself around it is the pulsar wind nebula so it's taking all that
15:06leftover stuff from the supernova and blowing it out into that expanding cloud
15:13the pulsar winds plow through the surrounding gas creating the twists and folds of the crab nebula
15:20supernovas create the elements
15:32their winds spread them throughout the cosmos
15:36forming new nebulas nebulas that might form a solar system like ours
15:43the nebula is essentially the starting point of uh of the recipe for the solar system so it's got
15:52all the ingredients all of the chemicals all the gases solids that we see in our solar system today
15:59think about the major elements that make up the planet earth what happened to bring all that together
16:04how did a gassy cloud of elements become our planet and our sun what turned a nebula into our solar system
16:26once upon a time there was no sun no solar system no us just a cloud of gas and dust a solar nebula
16:45we are here today because billions of years ago there was a nebula containing all the necessary ingredients
16:56everything that we see in our solar system today that was all part originally of the
17:02cloud of gas and dust that was our solar nebula
17:07almost five billion years ago a solar nebula was prepared to give birth to our sun
17:12so we have billions of years ago our solar nebula cloud of gas and dust and it's hanging out but
17:20it's unstable what tips the balance to turn a cloud of gas into solid objects something has
17:28to change inside a nebula something has to trigger the formation of stars and planets and that remains
17:34a mystery so what's the answer to this five billion year old mystery
17:42a mystery so what's the answer to this one is a mystery so what's the answer to this one is a mystery
17:47there are two theories
17:50both start with fossils fossils fossils that make their way from the edge of the solar system
17:57towards earth break through our atmosphere and find their way to us
18:03meteorites meteorites are really important for us to understand and study because they're time capsules
18:14to when the solar system was basically first forming
18:19mina wadwa curates one of the largest collections of meteorites on the planet
18:25these rocks hold a pristine record of the very early history of the solar system
18:31there was nothing else around in the solar system before these rocks were formed there was no earth
18:38there were no other planets it's it's mind-blowing the first solid objects form out of a cloud of dust
18:46surrounding our newborn star asteroids and meteorites forming at the same time contain the chemical
18:53fingerprint of our solar nebula they actually contain some of the oldest materials oldest solids
19:01that condensed from the cloud of gas and dust as our solar system was forming and so they came
19:06together and formed this this big rock that you see here in 2017 researchers analyzing the composition
19:14of a type of rocky meteorite called chondrites find a clue about how our solar system was formed
19:23there might be in fact a smoking gun somewhere in the chemistry of these rocks that could tell us about
19:29what exactly happened and how our solar system was formed this smoking gun is a radioactive element
19:36called iron 60 and it's thought to be created only in supernovas
19:46if you have a nebula which is about ready to start forming stars and a supernova goes off next to it
19:51that supernova is going to dump all those heavy elements into that gas cloud
19:56but it's also going to trigger the formation of stars by slamming into that gas and compressing it
20:04a nearby star goes supernova the shock wave strikes our solar nebula injecting it with iron 60
20:16but the collision starts a runaway gravitational collapse in the core of the nebula
20:21the gas cloud clumps together becoming hot and dense our sun is born as the sun is forming there's
20:33basically a cloud of junk all around the sun and as it orbits the sun it kind of accretes or sticks
20:40together and grows into these balls over the next hundred million years these balls get bigger and bigger
20:49forming asteroids moons and planets
20:55all of the planets in our solar system seem very different some ice giants some gas giants some rocky
21:01bodies but in fact all of these planets came from the same pre-solar nebula
21:08and on one small planet the right cocktail of elements gave rise to us
21:18everything every atom in our bodies was once part of the pre-solar nebula
21:26the theory that a supernova nudged our solar system into existence is compelling
21:31but not everyone agrees sometimes the biggest arguments amongst scientists are caused by the
21:38littlest things and in this case i'm talking about little tiny radioactive atoms
21:46in 2017 studies reveal other meteorites contain a different radioactive signature
21:53a rare isotope of aluminum called aluminum 26
21:58that's a rather odd atom that is not formed very easily in supernovas so that had to come from
22:05somewhere else
22:07that somewhere else is a rare type of giant star 40 to 50 times the mass of our sun a wolf raye star
22:19stars could be very weird and the very massive stars are incredibly weird the largest type of star that
22:26we've seen is what's known as a wolf rayette star
22:32wolf raye stars burn the hottest of all stars producing heavy elements like aluminum 26 during
22:38their short lives these are massive and hot and luminous and they blow off a tremendous wind
22:47this stellar wind ejects tons of matter from the star into the surrounding space creating a bubble structure
22:57scientists see this process at work in the bubble nebula 7 000 light years from earth
23:05in the middle of the nebula is one of these giant stars with a massive stellar wind high energy
23:10particles radiation and just like the name suggests it's blowing a bubble in the larger nebula around it
23:16the walls or shell of the bubble are dense and full of matter the stellar wind pushes more and more matter
23:26into the shell
23:29until this material collapses under its own gravity and condenses into stars
23:35it's entirely possible that what we're seeing in the bubble nebula is what happened here four and a
23:42half or more billion years ago to form the sun and the planets if our solar system formed within a wolf
23:50raye bubble nebula it would explain why so much aluminum 26 is present in meteorites
23:57but the jury is still out
24:04what we do know is that our story began with the collapse of the solar nebula
24:12but one day our star will die will the sun turn into a stunning nebula or will it just fade to black
24:27northern nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula nebula
24:57The stars aren't big enough to go out with a bang.
25:03Some will just burn themselves out.
25:08But others can create beautiful nebulas with the misleading name,
25:13Planetary Nebulas.
25:17From a distance, they look like planets.
25:19But really, they're the ghosts of stars.
25:23When stars like our sun begin to die, they bloat up into what we call red giant stars.
25:31As a sun-sized star reaches the end of its life, its core gets hotter and hotter.
25:38As it heats up, the surrounding gas expands, transforming the star into a red giant.
25:44It gets so big, its outer layers are no longer held in place by gravity.
25:54The outer layers of that star begin to drift away.
25:58They kind of lose touch with that central core in the middle.
26:01And they just begin to blow into beautiful shells, beautiful colors, beautiful shapes.
26:06We call these dying stars planetary nebulas.
26:08We've discovered over 3,000 planetary nebulas in our galaxy.
26:14Some look like an hourglass, or it looks like an owl, or a clown, or a sphere, or a donut.
26:21But if they're all the ghosts of the same type of stars, why do they look so different?
26:27If you have a star that's just sitting there, no planets, nothing else around it,
26:31it's going to blow off its wind in a spherical shell.
26:34And so if you see a planetary nebula like that, it looks like a soap bubble in space.
26:38But only 20% of planetary nebulas have this perfectly symmetrical bubble shape.
26:46Most of them have these weird shapes.
26:48They can be two lobes, it looks something like two squids kissing.
26:53All kinds of different shapes to these things.
26:58Experts think the strange shapes of these planetary nebulas may be linked to how a star dies.
27:08And now, new research may reveal the fate of our own star.
27:12Would we be a beautiful, bright planetary nebula, or would we just fade away into darkness?
27:20For the first time now, we think we may have the answer.
27:25It's a long-running debate.
27:27Is our sun big enough to form a spectacular nebula?
27:31It's kind of a funny coincidence.
27:33The model shows that you need a certain mass to make a planetary nebula.
27:36By coincidence, the sun is pretty much right on that limit.
27:43The new data suggests that our sun is going to go out in style.
27:50As the sun dies, it'll expand into a red giant, filling up the sky.
27:56We're used to our gentle yellow sun coming over the horizon.
28:00So imagine a giant, bloated, brilliant red glowing ball coming over the horizon for the sunrise.
28:11The expanding sun engulfs Mercury.
28:15Then Venus.
28:18It'll cook the surface of the Earth.
28:21Turning it into a molten hell.
28:24So the sad news is, is that once the sun expands as a red giant, it will absolutely boil away the oceans on the Earth.
28:33Life will no longer be sustainable.
28:35It's like sticking your head in an oven set to broil.
28:38It's not like it's going to be a fun time on the Earth.
28:42Some think it could even mean the destruction of the planet.
28:45We think the sun will eventually become large enough to swallow up where the Earth is now.
28:51So instead of there being a sunrise and a sunset, we're going to find ourselves inside the sun.
28:56The sun sheds its outer layers, ejecting over half of its total mass, revealing the stellar core.
29:10And so when we look at this core, which is now called a white dwarf, about the size of Earth, they're very hot.
29:20Like hundreds of thousands of degrees.
29:23This white hot core radiates UV light and X-rays.
29:27These hit the outer layers of gas and turn them into brightly glowing rings.
29:37A planetary nebula that will shine for about 10,000 years.
29:43One thing is for sure, and that is the solar system, when the sun turns into a planetary nebula, is going to look a whole lot different than it does now.
29:50It will be unrecognizable.
29:51The planetary nebula will mean the end of the solar system as we know it.
29:59The sun will eventually die away and unravel itself back into space.
30:04But then the cycle begins again.
30:06This is not just an ending, it's also a new beginning.
30:10It's going to provide the ingredients that will foster yet a new solar system.
30:15As one solar system dies, another solar system is born.
30:23So really this is the cosmic cycle of life.
30:26Nebulas always signal change in the universe.
30:31Intimately linked with star birth and star death.
30:35Now, new observations reveal that some of our favorite nebulas are also dying.
30:44Could the famous pillars of creation be dead already?
30:48Deep inside the Eagle Nebula is a dense region of cold molecular gas.
31:02Perhaps the best known image in all astronomy, the pillars of creation.
31:22One of the images that really changed things was the pillars of creation.
31:26And it was an image that was very evocative.
31:28It really made me feel very emotional.
31:33The pillars are five light years across and silhouetted by the light from a nearby star cluster.
31:40And it was these stars that carved out the shape of the pillars.
31:47The surface of these stars are energetic and boiling and constantly streaming particles off of them.
31:5410,000 mile an hour stellar winds ravage the surrounding gas clouds.
32:00Eventually, they completely dissipate their surrounding nebula.
32:06As the nebula disappears, columns of thicker, denser clouds survive.
32:13But for how long?
32:14When you look at these beautiful Hubble images of the pillars of creation, the Eagle Nebula, you see some blue, very diffuse gas around the pillars themselves.
32:25And this is a clue as to how the pillars formed and how they're going to change over time.
32:28This hazy blue gas is actually superheated material evaporating off the pillars themselves.
32:39Nearby stars are slowly eroding the pillars.
32:43This is similar to how weather erosion works here on Earth.
32:46Think about Monument Valley.
32:50You have these amazing stone pillars and really unlikely shapes coming up out of the ground.
32:56Well, those are denser areas of rock that used to be covered up by soil and sand.
33:01Over millions of years, that lighter material was blown away, exposing the denser rock underneath.
33:07And that's exactly the same thing that's happened here.
33:09This process is ongoing. Nebulas like the pillars are constantly evolving.
33:18The thing you keep in mind about the pillars of creation is this is actually a pretty transient feature in the life of the galaxy.
33:24It's not going to last forever.
33:26And in fact, over the course of time, even that we've taken images with the Hubble Space Telescope, we've seen it change.
33:32When astronomers compare new data to the original Hubble image from 1995, they discover a jet blasting out of the nebula at 450,000 miles an hour, extending 100 billion miles into space.
33:54What could be the source of all this energy?
33:57These jets are associated with the moment a star turns on.
34:02The stars being born inside of the pillars are basically eating their way out.
34:07They're eating up this material and then they're going to blast it away.
34:12Newborn stars are a lot like little kids on a sugar rush.
34:15They gorge on gas, then spin out of control.
34:19But stars also have a magnetic field.
34:23That magnetic field is rapidly rotating.
34:25It's sweeping up this material around it and shooting it out in two jets going out of the poles of the star.
34:33Jets and stellar winds are destroying the pillars of creation from the inside out.
34:43What's more, some of these baby stars are growing so fast they could soon reach the end of their short, violent lives.
34:50Wind stars die.
34:51They send shock waves, high energy radiation, particles.
35:00Supernova explosions like these could blow the pillars to pieces.
35:04Some have already suggested that the pillars may have already been destroyed thousands of years ago.
35:18Eagle Nebula is about 7,000 light years away.
35:21Eagle Nebula is about 7,000 light years away.
35:24And so we are literally seeing the Eagle Nebula as it was 7,000 years ago.
35:28Not as it is today.
35:30It's a sad fact of life.
35:33Nebulas are destroyed by the stars they create.
35:36That's happening all the time.
35:39Everything changes.
35:40Our most famous, favorite nebulas don't exist forever.
35:44And it might seem really sad, but this is just how the universe works.
35:49It's a transitory state.
35:51It's something in the act of changing.
35:54Where today we see pillars of creation, in the future they'll just be clusters of stars.
36:02But this eternal recycling of gas and dust into stars can't last forever.
36:09Nebulas across the universe are disappearing.
36:12Is our galaxy running out of gas?
36:38New research shows that across the universe, the birth rate of stars is falling.
36:45Fast.
36:47Researchers predict that 95% of all the stars that will ever exist have already been born.
36:54In order for a galaxy to be healthy, to keep making stars, it needs to keep collecting new reservoirs of gas, of raw material.
37:04Our galaxy is running out of gas, and in fact, galaxies all across the universe are slowly running out of gas.
37:13That cycle is winding down, and someday it will stop.
37:19More and more gas is locked up in low-mass stars that never go supernova.
37:30And the massive stars that do go out in a blast push the gas away.
37:36Galaxies eject materials.
37:40Supernova winds and fountains are constantly sending streams of gas and particles outside the galaxy.
37:48But stars are not acting alone.
37:52They're in cahoots with something even bigger.
37:54Experts think the main culprit lies at the center of every galaxy.
38:01A supermassive black hole.
38:04In the past, even the Milky Way has experienced this gas loss.
38:08Just a few hundreds of millions of years ago, the central black hole was pretty massive, and it gobbled up some material.
38:17In this process, it released a lot of energy. It sort of burped up a lot of energy.
38:23It released gas, and some of that probably escaped the galaxy altogether.
38:26Right now, our galaxy is still forming stars.
38:39But the gas tank needs refilling.
38:42Galaxies run on hydrogen.
38:45It's what creates nebulas, what creates stars.
38:48So it looks now like we may have reached a bit of a refueling stop.
38:51In space, we've discovered a giant cloud of hydrogen heading right for us.
38:57This hydrogen cloud is massive.
39:0110,000 light years long by 3,000 wide.
39:06Scientists call it Smith's Cloud.
39:10The thing is, it's orbiting our Milky Way, and in about 27 million years, it's going to slam into the disk of our galaxy.
39:18The collision will re-energize the galaxy, jump-starting star formation.
39:24There's a lot of gas in there. There's about a million times the mass of the sun. You could make a million suns.
39:32But this is only a snack.
39:35To keep forming stars, the galaxy needs regular feeding.
39:39Here in the Milky Way, we're still forming stars. And that's because our galaxy is a cannibal.
39:47It's surrounded by dwarf galaxies, and it's eating them. And it's stealing their gas and their dust.
39:52We're the product of mergers. Many small galaxies coming together and colliding.
39:59When a new galaxy collides with the Milky Way, it brings with it new gas, new dust, the potential to form new nebulas.
40:06So, by eating its own kind, the Milky Way is pulling out a few billion more years of star formation.
40:16But our galaxy is always looking for its next meal. And in a few billion years, it will feast on its next-door neighbor, the Andromeda galaxy.
40:28When Andromeda merges with the Milky Way, it's almost certainly going to deliver a fresh amount of gas.
40:36Although this is a catastrophic train wreck on a galactic scale, it's actually kind of a good thing.
40:43Because when it happens, more stars will be born inside of the Milky Way.
40:47That's going to extend the life of our galaxy, if you want to think of it that way.
40:50But there are only so many galaxies nearby for the Milky Way to feed on.
40:56Eventually, over the long run, the nebular gas is being used up.
41:00When that gas is gone, that's it. You can't form any more stars.
41:04And so whatever happens at that point, that will be the last generation of stars.
41:11With no gas to replenish them, nebulas will disappear across the universe.
41:16The universe really is winding down. Nebulas themselves are being depleted and dying away.
41:24The last stars will eventually blink out.
41:29From here on out, everything goes dark.
41:33Nebulas. One of the most spectacular features of the universe.
41:40One of the things that make nebulas so appealing is that they're just so beautiful.
41:44But it's more than just beautiful.
41:47They are cradles of creation.
41:50Nebulas are quite literally the starting point and the ending point of stars and therefore planets in life.
41:56I think it's incredible that we can learn about the cosmos.
42:00And I think in the end, we're really learning about ourselves.
42:03They are our connection to the cosmic circle of life.
42:07Nebulas are almost like an analogy for our own lives.
42:14They're incredibly beautiful.
42:16But yet, they're transitory.
42:18They're not going to be here forever.
42:20And that's the story of our universe.
42:23It's a story of change.
42:24So, seize the day.
42:28EUS
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