- hace 2 meses
Categoría
📺
TVTranscripción
00:01The night sky.
00:04Countless stars and the majestic sweep of the Milky Way.
00:09But beyond our local neighborhood, across the cosmos,
00:13there are over two trillion more galaxies.
00:17When we first began to observe galaxies, we collected them like butterflies.
00:22Little by little, we realized that they formed a web.
00:25The cosmic web is the infrastructure that connects every corner of the universe.
00:31You don't know anything about our universe if you don't understand the cosmic web.
00:35It feeds galaxies, it forms galaxies, it is made of galaxies.
00:41It's the architect of everything, and our cosmic future depends on it.
00:48The cosmic web is one of the most important parts of our universe.
00:52It plays a key role in the evolution of the cosmos.
00:56Without the cosmic web, there would be no stars, no planets.
01:00Nowhere in the universe where the conditions of life could exist.
01:04How did the universe go from a hot soup of gas to a cosmic web,
01:09sprinkled with galaxies, planets, and us?
01:14The universe may appear random.
01:32Two trillion galaxies spread across the cosmos.
01:36But in this cosmic chaos, scientists detect water.
01:45When we first saw that the universe was full of galaxies, it seemed like overwhelming chaos.
01:51But it's not. They are all connected.
01:54Galaxies link up in a gigantic cosmic network spanning the entire universe.
02:00How this pattern emerged may be cosmology's biggest puzzle.
02:08In some senses, you don't understand something unless you understand how it comes into existence and how it's formed.
02:15And galaxies are the basic building block of our universe.
02:19To solve this mystery, scientists need to go deep.
02:24To the very edge of the observable universe.
02:28And study light from the first galaxies.
02:35Chile, 2021.
02:37Scientists point the VLT, or Very Large Telescope, towards the Hubble Ultra Deep Field.
02:44It's a patch of sky famously photographed by the Hubble Space Telescope in 1995.
02:52The VLT's power allows astronomers to see much deeper into space.
02:58Imagine you take a grain of sand and you put it on your fingertip.
03:02And you hold your arm out like this.
03:04And you block a part of the sky looking at that grain of sand.
03:08That's the size of the Hubble Ultra Deep Field.
03:11And yet it contains thousands of galaxies in it.
03:16The telescope stares at those galaxies for 155 hours and picks up the faintest of glows.
03:25Ancient hydrogen gas concentrated along a strand of space 15 million light years long.
03:35The filaments are just one tiny section of the cosmic web.
03:41The largest known structure in the universe.
03:45The scale of the cosmic web is enormous.
03:50It is, by definition, the largest thing that we can see in our universe.
03:54Today, the cosmic web is a lattice of filaments, linked streams of hydrogen gas,
04:03that form an intergalactic network spanning the entire universe.
04:08Inside the nodes of the cosmic web, you'll find galaxies, stars, black holes.
04:14Along the filaments, you'll find gas that connects these nodes.
04:18And the gas will connect to the other galaxies and clusters of galaxies.
04:22It's this beautiful superhighway of large cities that are connected through these filaments.
04:30We can see the cosmic web about as far back as we can look.
04:35And really, galaxies are forming along that web all the way back.
04:39This cosmic infrastructure dates back to the earliest days of the universe.
04:4513.8 billion years ago, the universe ignites in a tiny ball of superhot energy.
04:59It expands and begins to cool.
05:04Energy transforms into primitive subatomic particles of matter.
05:10The heat from the Big Bang is so intense, gravity is effectively powerless.
05:16The very early universe was super hot, super energetic,
05:20and regular particles of matter were zipping around so fast that not even gravity could hold them together.
05:26But regular matter wasn't the only thing in the early universe.
05:30In the background, gravity is working on something else.
05:35Regular matter's ghostly cousin, the invisible substance known today as dark matter.
05:42It makes up about 85% of all the matter created in the early universe.
05:48Normal matter and dark matter both existed around the time of the Big Bang.
05:53But the way they played out was very different.
05:56Just 10 seconds after the Big Bang, the infant universe is billions of degrees Fahrenheit.
06:03Still far too hot for regular matter particles to clump together.
06:08But dark matter plays by different rules.
06:11Dark matter isn't affected by the Big Bang's intense radiation in the same way that regular matter is.
06:18And so because it's able to cool, it clumps together in a way that regular matter doesn't.
06:24As dark matter clumps grow, they exert a gravitational pull and begin to form shadowy structures.
06:33As soon as the dark matter gets a foothold, we have a place where there's a bit more stuff.
06:37Then that attracts more and more dark matter.
06:40380,000 years after the Big Bang, the intense heat drops to a few thousand degrees.
06:49Normal particles of matter move around more slowly.
06:53Protons and electrons bind together and form atoms of hydrogen and helium gas.
07:00Then gravity from dark matter starts to work on regular matter.
07:06Before you know it, you have this very clumpy universe with these huge dark matter halos
07:11that can now start to draw in also ordinary matter in the form of gas.
07:16A billion year building project begins.
07:21The dark matter clumps pull in clouds of gas.
07:25The foundations of the cosmic web and the galaxies.
07:31Just as when you build a building, you know, there's a lot of work that happens before the building goes up.
07:37Our universe spent a lot of time laying the groundwork for this cosmic web before it switched on the lights.
07:43The foundations are complete, but the job isn't finished.
07:49How did those clouds of gas transform into the greatest structure in the universe?
07:55The secretive dark matter that brought the gas together is also on-site managing the build.
08:05It was really the dark matter that called the shots in cosmic clustering,
08:10because it outweighed the ordinary stuff by a big factor.
08:14In essence, the cosmic web is made of dark matter.
08:18Tendrils of material are stretched out across the cosmos.
08:21As the sprawling structure builds, its gravitational pull strengthens, pulling in more dark matter.
08:30The clumps begin to collapse and shrink down into filaments.
08:35These meet at even more tightly packed clusters, creating a huge dark scaffold that drags in more hydrogen gas.
08:44Imagine drops of dew on a spider web.
08:47That's like hydrogen blobs being pulled into dark matter's cosmic web.
08:54After tens of millions of years of construction, strands of gas stretch across the cosmos.
09:02Fast forward to now.
09:05The web appears in all its star-spangled glory, lit up with galaxies.
09:11We know at some point stars and galaxies formed.
09:14The big question is when.
09:15What were the first galaxies like?
09:17That's a big mystery.
09:19So, how then did the lights of the cosmos switch on?
09:23Evidence suggests that as the universe assembled its web of dark matter and hydrogen gas,
09:30the biggest stars that have ever lived set the cosmos ablaze.
09:352018, scientists study an ancient galaxy, the catchily named MACS 1149-JD1.
09:54There, they find some of the oldest stars ever detected.
10:00This particular galaxy is exciting because it's forming stars just a very short time after the Big Bang.
10:07Those stars could hold clues as to how the cosmic web that supports the universe first lit up.
10:15But, as astronomers study starlight from when the universe was just 250 million years old, they get a shock.
10:25The stars are not just made up of hydrogen and helium produced in the Big Bang.
10:30They also contain what astronomers call metals.
10:36Metals in astronomy is everything heavier than hydrogen and helium.
10:41No matter where it is on the periodic table, if you're not hydrogen or helium, you are a metal.
10:47Even though that makes no sense.
10:49If I were king of astronomy, metals is right out.
10:53The Big Bang only made hydrogen and helium.
10:56Anything heavier than that was churned up in the cores of dying stars.
11:02The bright stars of this ancient galaxy, dating back to just 250 million years after the Big Bang, contain chemicals that were created in even earlier stars.
11:16Some of them seem to be nearly the age of the universe, extremely old.
11:21And yet they contain elements that guarantee they can't have been the first generation.
11:26As old as these stars are, there must have been something that came before.
11:31The earlier first generation of stars remains cloaked in mystery.
11:36How did the first stars ignite?
11:40And did they kickstart the formation of the first galaxies?
11:45It sounds like a classic creation myth.
11:51It's out of the darkness, out of nothing.
11:54Structure arrived and from that structure, the galaxies, the lights in the universe turned on.
12:02We've never seen a first generation star.
12:05But physicists have a theory of how they formed and what they were like.
12:10Let's step even further back in time, to around 100 million years after the Big Bang.
12:18The early cosmic web is dark.
12:21There are no stars to illuminate it.
12:23But the universe is ready for stellar ignition.
12:29Cooled down after millions of years of expansion,
12:35the gas clouds clinging to the dark matter scaffold begin to contract.
12:42As the hydrogen gas clumps together, larger clouds form super dense, ultra-hot cores.
12:50If you can bring hydrogen together and actually get it hot and dense enough,
12:56hydrogen will begin to fuse into helium.
12:59There will be a nuclear fusion reaction going on.
13:02Simulations suggest that some gas clouds are hundreds of times the mass of the sun.
13:11The stars they produce are unlike anything that exists today.
13:17So the stars around us today really top out at masses between, let's say, you know, 70 to 100 times the mass of our sun.
13:25There's nothing larger than that.
13:27These first stars were up to 1,000 times more massive than the sun.
13:34So if you plopped it in our solar system, it would extend all the way past Jupiter.
13:39So think about that.
13:40That is incredibly big.
13:42That scale is mind-blowing.
13:44So what happened to these stellar behemoths?
13:50The lifetime of a star has a lot to do with its mass.
13:53The more massive a star is, the more gravity crushes the interior up to high temperatures,
13:58and it burns through its nuclear fuel even faster.
14:01So, incredibly, the more mass there is, the shorter a lifetime you get for a star.
14:06The first generation of stars are sort of like the rappers and rock stars of the universe.
14:14They live fast.
14:15They die young.
14:16First generation stars didn't live long enough to form complex galaxies, but they did set the process in motion.
14:27The lives of the first stars may have been rock and roll, but their explosive deaths in supernovas pumped the universe full of heavy metal.
14:40In the galaxy today, we see a supernova maybe every couple of years, close to us every couple of decades.
14:46This must have been a firework show.
14:48Giant supernovas going off all the time, all around you.
14:52That act of destruction is actually an act of creation.
14:58What a star does in its core is it creates heavier elements from lighter elements.
15:05That first generation of stars must have been absolutely incredible.
15:09Simply exploding so quickly and unloading all of this wonderful new chemistry into the galaxy.
15:16200 million years after the Big Bang,
15:20The remains of the first stars flood the interstellar medium with heavier elements like carbon, oxygen, silicon and iron.
15:32Crucial ingredients for the next wave of stars.
15:36It's such a beautiful story because suddenly the whole process of star formation changed and it literally became easier to make a star.
15:46Heavy elements suck heat out of the surrounding gas.
15:50Cooler clouds crunch down much faster.
15:53The smaller, second generation stars form rapidly and in much greater numbers.
15:59Somehow, this mess of stars transformed into a network of young galaxies.
16:06But it wasn't easy.
16:08Because as these baby galaxies formed, a breed of matter hungry monsters appeared in the young cosmic web.
16:1613.6 billion years ago, the dark scaffold that supports all the regular matter in the universe emerges ablaze with stars.
16:35But how did this stellar array evolve into a structure littered with organized galaxies?
16:41It seems they formed under constant threat of destruction.
16:46October 2020.
16:52Astronomers discover a monster lurking among the cosmic web's earliest structures.
16:58Dating to 900 million years after the Big Bang.
17:02A supermassive black hole.
17:05Six galaxies surround this cosmic giant.
17:09Caught in its grip, seemingly linked to the supermassive black hole by filaments of the developing cosmic web.
17:18It's like the universe has given supermassive black holes an umbilical cord.
17:24It's like an all-you-can-eat buffet right there.
17:28Supermassive black holes are hungry beasts.
17:33They feast on any matter that gets too close to them.
17:37Supermassive black holes are likely some of the most powerful objects in the universe.
17:43They can be anywhere between 100,000 to 10 billion times the mass of the sun.
17:49Supermassive black holes have been a nemesis for generations of scientists.
17:55Not because of their fearsome nature, but because nobody knows how they grew so large so early.
18:03I wish I knew where supermassive black holes came from.
18:06If I knew, I would have a Nobel Prize hanging around my neck and I would wear it every single day.
18:11As someone who deeply loves supermassive black holes, whose career is based on studying supermassive black holes, it is very frustrating to not know where they come from.
18:25Regular stellar black holes are the collapsed cores of dead stars, ranging from three to thousands of solar masses.
18:35But supermassive black holes? Those are a different beast.
18:3913 billion years ago, not enough stars had lived and died to build something as huge as a supermassive black hole.
18:51Now, the cosmic web offers scientists clues about the black hole conundrum.
18:58We now know supermassive black holes grow among the lattice of the young cosmic web, gorging on the hydrogen gas that travels along the filaments.
19:10At the same time, when the cosmic web is lighting up, supermassive black holes appear to be stealing star fuel from the young universe.
19:20You might think that would kill a growing galaxy. And yet, most mature galaxies have a supermassive black hole.
19:29They really dominate the physics of what happens in the centers of galaxies and even how galaxies can evolve.
19:36We think these galactic monsters have been around from the start.
19:41How then did the web's young galaxies develop around supermassive black holes?
19:48The Milky Way's supermassive black hole is called Sagittarius A-Star.
19:54It's around 27 million miles wide and weighs in at just over 4 million solar masses.
20:04The environment around Sagittarius A-Star is very dynamic.
20:09It can actually be a really hellish place.
20:12There's this accretion disk that's full of plasma, seated to thousands of degrees.
20:17So you wouldn't necessarily think that that's a great place for star formation to happen.
20:24But that's exactly where astronomers decided to look.
20:29Using the Atacama Large Millimeter Array, or ALMA for short, scientists scan the heart of the Milky Way for dense cores of gas and dust, stellar embryos.
20:42They found more than 800 within just a thousand light years of Sagittarius A-Star, including more than 40 embryos with energetic jets blasting from their cores.
20:55The telltale sign of the birth of stars.
20:58It's really surprising to find those stars there.
21:04It's like hearing babies' cries from a wolf's den.
21:10It's not the place you would expect this to happen.
21:13But in fact, stars are forming there.
21:16Now, it's not as efficient as it is out here in the suburbs where things are quieter, but it works.
21:21Baby stars igniting and thriving around a supermassive black hole.
21:28The kind of hostile environment we know existed in the young cosmic web.
21:33Star birth is a key part of kick-starting young galaxies.
21:37This evidence suggests that star formation is more resilient than researchers thought.
21:44And they've developed a theory to explain it.
21:49Gas and dust race around the black hole in the accretion disk.
21:53Heated to incredible temperatures, plumes of gas break off and blast into space.
21:59The gas rapidly cools, collapses, and forms baby stars.
22:04These accretion disks are the most chaotic of stellar nurseries.
22:09You see this mechanism that you think is violently inhibiting star formation, and at the same time it's triggering the birth of new stars.
22:18Matter clumps at the cosmic web's intersections, feeding the supermassive black holes.
22:25Around them, stars burst into life, slowly building galaxies.
22:31This could be how our own Milky Way formed among the filaments of the young cosmic web.
22:38But new research suggests that growth in these baby galaxies requires murder and mayhem.
22:47And without them, we wouldn't exist.
22:50The infant universe is a dramatic place.
23:03Stars ignite and stars die.
23:06Even in the violent surroundings of supermassive black holes.
23:10Baby galaxies form with the cosmic web.
23:15But how do they grow?
23:18Scientists believe the critical factor is galactic turmoil.
23:22The universe does need to churn things up.
23:27You need to break some eggs to make an omelet.
23:29You need to introduce some chaos into your galaxy to rapidly form stars or grow black holes.
23:34Smashing things together is how the universe came to be.
23:40The Hubble Space Telescope discovers many distorted galaxies.
23:45Twisted, battered, and torn.
23:49Victims of violent collisions on a cosmic scale.
23:55Galaxies are never sitting quietly doing nothing.
23:59They're always undergoing change.
24:01They're constantly encountering and slamming into and colliding with and mixing with other galaxies.
24:07You can see images in Hubble of total car wrecks of galaxies that are trying to merge with each other.
24:14We know that galaxies collide now.
24:19But what about in the early universe, when the cosmic web was beginning to take shape?
24:25Astronomers study a strange galaxy named Himiko, born just 800 million years after the Big Bang.
24:34Three bright light sources suggest intense star formation.
24:40Detailed analysis reveals not one galaxy, but three baby galaxies, not yet fully formed.
24:48Scientists call these youthful star systems proto-galaxies.
24:55The trio that make up Himiko are in mid-collision.
24:59Computer simulations of the early universe suggest proto-galaxies smashed together with frightening regularity.
25:08These violent shakeups trigger star birth.
25:13Proto-galaxies are rich in gas.
25:16When they collide and merge, those gas clouds collide and collapse and form stars, sometimes at prodigious rates.
25:23And after a billion years or so, all of that structure forms and you get a formal galaxy.
25:30Picture the early universe, 500 million years after the Big Bang.
25:35It's smaller and more compact than today.
25:38Cosmic collisions are common.
25:40Imagine taking a bunch of cars and just letting them drive around in Nevada where there's nothing but space, right?
25:47You're not going to get too many collisions.
25:49Now, squeeze them into a tiny little city block someplace and you're just going to have accidents everywhere.
25:55Well, it's the same thing with the universe.
25:57When the universe was younger, it was smaller and these proto-galaxies were everywhere.
26:01It was crowded.
26:02You were bound to get collisions between them back then.
26:06More and more baby galaxies form at the growing web's gas-rich intersections.
26:12A collision between small proto-galaxies might trigger modest amounts of star formation when regions of dense matter come together.
26:25But a merger involving proto-galaxies with rich reserves of gas can rev up the rate of stellar ignition, supercharging a growing galaxy.
26:36Gas-rich mergers can generate starburst galaxies where we see incredibly vigorous events of star formation.
26:44Astronomers think one such smash-up, around 10 billion years ago, kick-started the growth of the Milky Way.
26:52A group of stars called the Gaia Enceladus Cluster in the outer reaches of the galaxy behaves strangely compared to other stars around it.
27:02The stars in the Gaia Enceladus Cluster, they're different.
27:07They move differently.
27:08They act different.
27:09They're like kids from the next town over showing up at your school.
27:13You just know that they don't belong.
27:15The Milky Way had already largely formed.
27:19And then this massive cluster comes screaming in.
27:23It was a violent event that eventually ended up absorbing the stars from this cluster into the body of the Milky Way itself.
27:33Galaxies are built from these kinds of collisions.
27:37Less than a billion years after the Big Bang, the dark scaffold of the cosmic web begins to glow.
27:46Matter, channeled down the web's tendrils, creates dense clumps of gas.
27:52Even in the turbulent neighborhoods of supermassive black holes, stars burst into life.
28:00Baby galaxies collide and the young universe sparkles with light.
28:07But an important question remains.
28:10In the mayhem of the early universe, how did galaxies like our Milky Way survive and thrive?
28:20Galaxy evolution is very dynamic.
28:23Our understanding of galaxy evolution is very dynamic.
28:26And there's so much that we still don't know.
28:29There's a lot of different competing theories right now as to how galaxies grew into the galaxies that we see today.
28:37It's a huge open question and it's something that's a big deal in science right now.
28:42New research suggests that life and death in the cradle of the universe lay within the cosmic web.
28:5113.6 billion years ago, a proto galaxy, the infant Milky Way, forms in the tendrils of the young cosmic web.
29:07Today, it bears the scars of many collisions.
29:13Each one could have torn it apart.
29:16So what controls if a young galaxy lives or dies?
29:21May 2020. Scientists image a graceful galaxy that existed just 1.4 billion years after the Big Bang.
29:30Analysis of its light shows this is a starburst galaxy, pumping out newborn stars.
29:40Galaxies like our Milky Way are old and rather stately.
29:43And they don't form stars very rapidly, about the equivalent of the mass of the Sun every year.
29:49Well, starburst galaxies, yeah, they form them a lot more quickly.
29:53Hundreds of solar masses per year.
29:56But BRI 1335-0417, 4,650 times the mass of the Sun every year.
30:04It is blasting out stars.
30:08Some young galaxies in the early universe appear to be supercharged with star fuel.
30:14How can they grow at such an incredible pace?
30:20Scientists think the answer lies in the mysterious substance that's controlled the flow of gas since the beginning.
30:28The dark structure whose tendrils stitch the universe together.
30:32But exploring this cosmic network is no easy task.
30:38When it comes to dark matter, we're flying blind.
30:42May 2021. An international team of researchers investigates dark matter in the local universe by observing its effect on the path of light.
30:57Gravity affects light.
31:00A massive object causes light to curve through space, even if that object is invisible, like dark matter.
31:12We can't see the dark matter directly, but we can see what it's doing to the light.
31:15It's stretching it. It's bending it.
31:17It's creating arcs in ways that would never happen unless the dark matter were there.
31:21Using an AI program, the team analyzes 100 million visible galaxies, looking for warped galactic light.
31:32Because the model is artificially intelligent, it gets better and better at finding dark matter.
31:38What's very clever about this kind of algorithm is that it's learning as it goes.
31:47It uses the information that it has to predict the existence of new structures.
31:54As the model teaches itself to see the dark matter behind the stars, it maps out new dark structures, never-before-seen highways between galaxies.
32:05There's a lot more filaments, there's a lot more intricacies, there's a lot more cosmic web there than what meets the eye.
32:14It's like, if you look how Manhattan is connected to the land around it, you can see all the bridges, but now we're also seeing the underwater tunnels.
32:24The new layout of dark matter reveals the local universe is a bird's nest of hidden channels feeding galaxies with gas.
32:35Galactic structures seem to thrive at the cosmic web's most densely knotted intersections.
32:43Because multiple filaments are intersecting in those locations, and that is a location of very enhanced gravity relative to other locations, then material will be drawn in.
32:58So these galaxy clusters are likely feeding off the cosmic web.
33:02This connectivity could be the key to the rapidly forming galaxies in the early universe.
33:11But there's a catch.
33:13Sitting right at the densest regions of the cosmic web can be really good for galaxy growth.
33:19You have all of this gas being funneled in for new star formation, but being that plugged into the network isn't all good news.
33:26There is evidence that, though the cosmic web gives life, it can also take life away.
33:34Scientists studying some of the universe's most heavily connected galaxies found something unexpected, plummeting rates of star birth.
33:44In some ways it's a little bit counterintuitive, right?
33:46If these nodes are meeting grounds for all of this gas, right, why aren't you forming more stars there?
33:54One explanation? In the all-you-can-eat buffet of the cosmic web's matter-rich junctions, a young galaxy might overindulge.
34:05As the cosmic web funnels more matter towards a junction and its growing galaxies, the gas influx doesn't just boost star formation.
34:17It fattens up the supermassive black hole at the galaxy's core.
34:21For a young galaxy, that's dangerous.
34:25Because when this monster overeats, it produces high-energy jets and belches out super-hot wind.
34:34These black holes radiate tremendous amounts of energy when they grow.
34:39And that radiation can slam into the material around them in the galaxy and blow it all out of the galaxy, launch it away or heat it up to super-high temperatures.
34:47Star formation requires stuff. So if you blow that stuff away, how are you going to form a star?
34:57And what's left behind would be what we call a quenched galaxy that basically can't form any new stars.
35:03The researchers found that although connectivity within the cosmic web can boost galactic growth, it was the super-connected galaxies that died the quickest, choked and stunted like over-watered plants.
35:19Perhaps our Milky Way got lucky.
35:22You could say that the Milky Way galaxy is sort of in this Goldilocks zone of galaxy formation.
35:29It's been receiving enough gas over time that it's been able to keep up with its star formation.
35:35But not so much gas that its central black hole has been fed enough that it would clear the galaxy out of gas.
35:42The cosmic web determined if galaxies lived or died. Its construction project brought order to chaos.
35:53The cosmic web is the architect, the engineer, the builder, the construction worker, even the interior designer of the cosmos.
36:02But now work is shut down. An invisible force threatens to tear apart the very fabric of the cosmic web.
36:13What does this mean for galaxies and for us?
36:17The cosmic web brought order to the early universe.
36:32The gravitational attraction of its dark scaffolding helped build galaxies and fueled their development.
36:39But growth tops out at the level of galaxy clusters. Nothing bigger will ever form.
36:45Something has stopped the formation of structure in our universe.
36:52To understand what's going on, we need to return to the Big Bang and the formation of the cosmic web.
37:0013.8 billion years ago, the universe sparks into life.
37:08A tiny ball of pure energy cools and expands.
37:12The energy transforms into regular matter and dark matter.
37:20But another force appears at the same time.
37:25Dark energy.
37:29Dark energy, as far as we understand it, which is not much, has always been here.
37:35It's always been a part of the universe, but it's been silent in the background.
37:41Dark energy is everywhere. It's over here. It's over there. It's between you and me. It's absolutely everywhere.
37:48One theory is that dark energy never formed. That it's just a constant in the laws of physics. It has always been there and always will be.
37:58Some physicists believe that dark energy is simply the force of emptiness.
38:04People used to take for granted that space was empty, vacuum.
38:11But the discovery of dark energy has made some people wonder if space is actually more of a substance.
38:18And that space also might have pressure that causes things to push apart.
38:22So, you know, whatever space is, it might be more interesting than we thought.
38:28Dark matter dominates the young universe.
38:33But as the dark scaffold of the cosmic web grows, it sows the seeds of self-destruction.
38:39As the network of matter takes shape, pockets of emptiness form between the filaments, cosmic voids.
38:53In these expanding hollow spaces, dark energy grows.
38:58The weirdest thing about dark energy is that it has constant density.
39:02Constant density means the more volume you have, the more dark energy you have.
39:09So the larger the voids get, the more dark energy they contain.
39:15Dark energy pushes against the cosmic web, opening up huge chasms in the architecture of the universe.
39:23Five billion years ago, dark matter's strength of attraction is finally overwhelmed.
39:29Like bridge cables in a hurricane, the cosmic web's filaments stretch and snap, and the universe's substructure fails.
39:40Galactic construction freezes as the universe expands.
39:45But darker times are ahead for the cosmic web.
39:49As time goes on, not only is it expanding, but this expansion gets faster and faster and faster.
39:56As the dark energy in the voids increases, the entire structure of the cosmic web begins to break up.
40:07The effects of dark energy will get stronger and stronger with time until the very fabric of space-time gets torn apart.
40:16This isn't a superhero movie. The bad guy wins.
40:21The future of the cosmic web is looking bleak.
40:25Ultimately, it's going to be a cold, lonely universe.
40:30Our closest galaxies will accelerate away until they're just tiny pinpricks of light.
40:37Then the universe will go dark again.
40:40Everything will fade out. So the universe started with a bang, but it will die with a whisper.
40:49The cosmic web transformed the universe from a hot mess to a sparkling structure.
40:56It gave birth to billions of galaxies and us.
41:00Without it, space would be a much less interesting place.
41:06This giant structure, the largest thing that we know of in the universe, is responsible for nourishing the galaxies, creating the stars, making the conditions right to form life.
41:17We would not be here talking right now if it were not for this cosmic web.
41:21Understanding the cosmic web is understanding dark matter, is understanding dark energy, is understanding our past, is understanding our future.
41:32Really, everything that we know about how the universe works is directly tied to the cosmic web.
41:38It's amazing to think that the overall structure of the universe that we witness today began in the earliest times of the universe and has yielded beings like ourselves who can now discover it and ponder about its existence.
41:57That's pretty dope.
Sé la primera persona en añadir un comentario