• 4 months ago
El profesor Brian Cox comienza su épica exploración del cosmos en esta excepcional serie documental de la BBC adentrándonos en los grandes cuerpos luminosos que aportan luz y calor al universo: las estrellas.

Se estima que hay doscientos billones de estrellas en el universo, cada una de las cuales desempeña su papel en una historia épica de la creación, una gran saga que se extiende desde el amanecer de los tiempos, con la llegada de la primera estrella, a través de diversas generaciones hasta la llegada. de nuestra propia estrella, el sol, y de un mundo y una civilización que han crecido gracias a su luz.

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00:00THE VARIETY OF THE UNIVERSE
00:16The variety of our universe is infinite.
00:21200 billion galaxies.
00:24Thousands and thousands of millions of stars.
00:33Countless planets.
00:36Worlds that surpass our imagination.
00:43The universe is so huge, so incomprehensible, so terrifying,
00:48that I think it's perfectly natural that we live our lives alien to it.
00:55Perhaps that's why we have that sense of relief when dawn comes.
01:01The brightness of the sky hides the stars and the questions they pose.
01:08They are the most transcendental questions.
01:14How was the universe formed?
01:17Why are we here?
01:20And how will it all end?
01:24THE VARIETY OF THE UNIVERSE
01:29If we want a deep understanding of ourselves,
01:32we have to face those questions.
01:36Astronomy is quite a challenge.
01:39From one perspective, we are nothing more than grains of sand drifting in an infinite and indifferent sea.
01:46But we are also the greatest creation of nature.
01:49Collections of atoms that can think,
01:52that can ask themselves questions about the universe,
01:55and choose to explore it.
02:12In our search for answers, we venture further and further away from home.
02:16Beyond the planets.
02:22On the path of the stars.
02:28Our spaceships send us a constant flow of extraordinary discoveries.
02:35Visions of alien worlds.
02:40That have the ingredients to create life.
02:47We have seen galactic clashes.
02:55Black holes devouring solar systems.
03:01And perhaps we have seen the origin of the cosmos.
03:09With every new observation, with every new knowledge,
03:13there is the opportunity to obtain a deeper understanding.
03:18And as we answer one question after another,
03:21we get closer and closer to being able to tell what is probably the greatest story ever told.
04:14NASA's Parker Solar Probe.
04:17A daring mission to shed light on the mysteries of our closest star.
04:34We could say that this is a journey to the country of never, never, ever.
04:43NASA's Parker Solar Probe is the first spacecraft to touch a star.
05:14It is designed to travel through the atmosphere of the sun.
05:20And it resists temperatures that no spacecraft has ever endured.
05:43NASA's Parker Solar Probe.
06:00Thanks to the Parker Solar Probe,
06:02we are getting to know our star as we had never known it before.
06:08That will help us tell the story of all the stars.
06:23Our sun comes from a long strip of stars that goes back to the beginning of time.
06:31From the intense blue giants that illuminated the universe,
06:35for the first time,
06:41until later generations.
06:46Whose deaths enriched the cosmos with the most valuable elements.
06:54The foundations of our solar system.
06:58The elements that allowed our sun to create what gives meaning to the cosmos.
07:11Life.
07:13All of us.
07:57We have a strange relationship with the stars.
08:00It goes from awe to indifference.
08:04We assume the existence of our star, the sun,
08:07probably because of its predictability.
08:10It rises in the east and sets in the west every day.
08:14Without any help or consideration on our part.
08:18But many ancient cultures deified the sun.
08:21They treated it as a god.
08:23And the sun gods were both creators and destroyers of worlds.
08:27So, what is the sun really?
08:31Well, I think that, in modern science,
08:33the modern story of the stars is that the sun is a god.
08:36And the sun is a god.
08:38And the sun is a god.
08:40And the sun is a god.
08:42And the sun is a god.
08:44I think that, in modern science,
08:46the modern story of the stars is an epic story,
08:49which goes back to more than 13 billion years,
08:52to the origin of the universe.
08:56And that places it clearly in the realm of the gods.
09:00If we want to understand where these gods come from,
09:03we have to go back to a time before the stars.
09:09So, the sun is a god.
09:12And the sun is a god.
09:14And the sun is a god.
09:18And the sun is a god.
09:20And the sun is a god.
09:23And the sun is a god.
09:26the stars.
09:56In the beginning, the universe was dark.
10:06But it was not empty.
10:13Something was lurking in that emptiness,
10:19spreading its net of claws.
10:26The net of the cosmic claw
10:43The cosmic net grew into a gigantic structure
10:52that crossed the entire universe.
10:57It was made up of filaments intertwined with dark matter.
11:08And at the intersections of the filaments
11:14is where the first stars were born.
11:26The first ancestors of our sun.
11:56The cosmic net is the scaffolding of the universe,
12:00a huge and intricate structure that occupies the void.
12:20The net is mainly made up of dark matter,
12:23a mysterious substance that dominates the universe.
12:27Although we do not know what it is,
12:29it is one of the great mysteries of modern physics.
12:32Probably some kind of particle
12:35that interacts very weakly with itself and not with light.
12:39As it does not interact with light, it cannot be seen,
12:42and that is why it is called dark matter.
12:45But its gravity does influence the universe.
12:54And it was in the dark heart of the cosmic net
12:58where gravity began to sculpt the primitive universe,
13:05uniting the two simplest elements, hydrogen and helium,
13:12the raw material of the first stars.
13:17Hydrogen is a gas that adheres to the filaments of the net,
13:22attracted by the force of gravity of dark matter.
13:26And where the filaments cross,
13:29the gas becomes so dense that it collapses by its own gravity
13:34until it forms clusters of galaxies,
13:37each of them made up of billions of stars.
13:47The universe was approaching a point of inflection.
13:52The hydrogen and helium of the regions where the filaments crossed
13:57began to concentrate in denser clouds.
14:17Gravity imposed all its force.
14:23And the gas clouds concentrated even more,
14:31becoming more and more dense.
14:37And in the densest areas, the gas warmed up so much
14:43that nuclear fusion reactions began.
14:48From that voragine, the first gods arose
14:55and became the first gods of the universe.
15:02The first gods of the universe.
15:09The first gods of the universe.
15:14And the light was made.
15:44The first gods of the universe.
16:06The stars illuminate the universe,
16:10but that is their least relevant effect.
16:15What makes the universe interesting,
16:18what gives true meaning to the universe, is that,
16:21life, you and me.
16:24Life is just chemistry.
16:27And chemistry needs complex chemical elements.
16:31But the only thing that existed in the universe before the stars
16:34was hydrogen and helium.
16:37Carbon, oxygen, iron,
16:40those elements were formed in a process called nuclear fusion,
16:43in the nuclei of the stars,
16:46and the heaviest elements, like gold, in the collisions of stars.
16:50Without the stars, the universe would have no interest,
16:54it would have no meaning.
16:57It would just be an infinite gas box.
17:08The first stars were monstrous.
17:20Hundreds of times larger than our sun.
17:28They burned with such ferocity
17:31that the temperature of their surface
17:35exceeded 100,000 degrees,
17:38and their brightness was blue.
17:45They were the largest stars that have ever existed.
17:49Violent and volatile giants.
18:05In essence, a star is an act of balance.
18:08The force of gravity tries to cause its collapse,
18:11causing the hydrogen atoms
18:14and the loose protons that make it
18:17to get closer and closer to each other.
18:20And when those loose protons get close enough,
18:23another of the fundamental forces of nature comes into action,
18:26the strong nuclear force, which is capable of hitting the protons.
18:29This releases an energy that, in turn,
18:32creates the pressure that keeps the star active.
18:35Now, the more massive the star,
18:38the stronger will be the attraction of gravity towards the interior.
18:41More energy will have to be released to maintain balance,
18:44and its components will be exhausted more quickly.
19:03These giant stars
19:06constantly fought for their survival,
19:17fighting the relentless force of gravity
19:20and consuming more and more fuel
19:23to maintain their precarious balance.
19:32When a star burns hydrogen,
19:35which only has one proton,
19:38and is the simplest of the elements,
19:41it turns it into helium with two protons.
19:44Now, when it runs out of hydrogen,
19:47the core of the star starts to collapse and heat up,
19:50and the star responds,
19:53producing more and more elements,
19:56which is why it's called a star bomb.
19:59It makes carbon with six protons
20:02and oxygen with eight protons,
20:05releasing more and more energy in the process.
20:12But when the star's interior accumulates iron,
20:15which has 26 protons in its core,
20:18no more energy can be released,
20:21and the star loses its battle against gravity.
20:24It collapses,
20:27and in a final act of creation before its destruction,
20:30it distributes through the universe
20:33those heaviest chemical elements
20:36just created.
20:40Imagine that we could travel through time
20:43and contemplate the brief luminous life
20:46of the first star.
21:10The first star
21:25Its fuel ran out after a million years.
21:40The core collapsed.
21:57The star imploded.
22:10And resurfaced
22:13with a colossal explosion,
22:16a supernova.
22:40The death of the first stars
22:43began to transform the cosmos.
22:49The immense ocean of hydrogen and helium
22:52that filled the universe
22:55was enriched with the new heavy elements,
22:58and with all this,
23:01new generations of more complex stars were formed.
23:10With time,
23:13these elements combined,
23:24generating very rich clouds of gas and dust.
23:39They were real nurseries
23:42where new generations of stars were born.
23:50And not just stars,
23:53but families of stars,
23:56the first galaxies.
24:00It was at this time
24:03that some of the first stellar systems
24:06were formed in our own galaxy,
24:09the Milky Way.
24:23A new era of complexity
24:26was dawning in the universe,
24:32with stars of different sizes
24:40and colors.
24:57And most importantly,
25:00new stellar bodies emerged.
25:10Planets.
25:13Places where the rich chemical elements
25:16created by the previous generations of stars
25:19could finally find a home.
25:27A new era of complexity
25:30was dawning in the universe.
25:39Countless billions of stars
25:42have appeared and disappeared
25:45since those first giants illuminated the darkness.
25:48Each of them has enriched the universe
25:51with matter that would give life to the next generation.
25:54Blue and white stars,
25:57individual and binary stars,
26:00even triple systems with three stars orbiting each other.
26:03The appropriate conditions were created
26:06for these stars to drive the universe
26:09towards a new and deep era of complexity.
26:24Our sun was formed
26:27from the ashes of generations of ancestors.
26:55It is only a small star
26:58in a galaxy with billions of brilliant gods.
27:13For its first million years,
27:16the sun was practically alone,
27:19enveloped in gas clouds,
27:22and dust.
27:29The dust slowly agglutinated,
27:36forming clusters the size of guillotines,
27:42then rocks,
27:46and finally, planets.
28:00But the planets were lifeless rocks.
28:09Only the sun had the power
28:13to turn them into worlds.
28:24Some were too far from the sun.
28:28The ice giants,
28:31frozen and apparently doomed to sterility.
28:39Others were too close.
28:42Embraced by its relentless light,
28:45they became deserted, calcined planets.
28:51But in the family of the sun,
28:54the sun was not alone.
29:01The sun was not alone.
29:07The sun was not alone.
29:12There was a planet
29:15that, by chance,
29:18did not form too close or too far.
29:27A place where our star
29:30could infuse life into dust.
29:43Part 2
29:58The planets are nothing more than
30:01the remains of the formation of the stars.
30:04Simple debris,
30:07small motes orbiting
30:11But the planets are also
30:14the places in the universe
30:17where gravity has concentrated
30:20the heavy elements
30:23that arose from the previous generations of stars.
30:26And that makes the planets
30:29the creative canvas of the stars.
30:32The canvas where the stars can create.
30:35And what do I mean by that?
30:38Not only are there rivers and mountains,
30:41there are also living beings.
30:44There are animals and plants,
30:47human beings and human civilization,
30:50the most complex entity we know in the universe.
30:53So we would have to ask ourselves
30:56how is it possible that such complexity
30:59has arisen in a totally casual way?
31:02The answer was already known
31:05in the 19th century
31:08thanks to the science of thermodynamics.
31:13In the 19th century,
31:16people were very interested
31:19in improving the efficiency of steam engines.
31:22Steam engines were the drivers
31:25of the factories that allowed
31:28to build increasingly complex things.
31:31It turns out that the only important thing
31:34is the difference in temperature
31:37between the fire in the oven
31:40that surrounds it
31:43and the cold that surrounds it.
31:46In the universe,
31:49the stars are hot spots
31:52in a cold sky.
31:55We are sitting inside a gigantic steam engine
31:58powered by the sun's oven.
32:01That is why the stars
32:04are the creators
32:07of the complexity of the universe.
32:13Creating complexity is a very subtle art.
32:19You need an engine,
32:22in this case a star,
32:25that is not too aggressive or bright.
32:29A star that remains stable
32:32during the necessary time
32:35to learn the sparks of life
32:42and allow those sparks to bear fruit.
32:59So that a star can sustain a civilization.
33:07Its main characteristic
33:10must be absolute reliability.
33:29No one knows exactly
33:32how life came to be on Earth.
33:43What we do know
33:46is that at some point
33:49the primitive cells that lived in the sea
33:52began to use solar energy
33:55to feed the chemical reactions
33:58that life depended on.
34:01Those cells established a bridge
34:04between Earth and the sun.
34:09Those delicate engines
34:12took advantage of the light
34:15that came from the fire of our star
34:18to convert carbon dioxide and water
34:21into food.
34:26This process, called photosynthesis,
34:29unleashed the creative power of the sun.
34:47It propelled the evolution of complexity.
34:56Starting with primitive bacteria,
34:59passing through plants and trees,
35:15until finally
35:18it came to us.
35:25Photosynthesis is a process
35:28that is very easily described in words.
35:31Plants take energy from the sun
35:34and use it to react carbon dioxide
35:37and water to make sugars
35:40and a waste product, oxygen.
35:43It's easy to explain and difficult to do.
35:46In everything we see here
35:49there is part of that machinery for photosynthesis.
35:52On our planet, photosynthesis is carried out.
35:55An intricate machinery
35:58with 46,630 atoms working together
36:01and very efficient
36:04after billions of years of evolution.
36:07Then we eat the plants
36:10or we eat something that has been eaten by the plants
36:13and we do the reverse reaction.
36:16We take the sugars and inhale that waste product, oxygen.
36:19Then we react together
36:22and we use that solar energy stored in the plants
36:25to maintain our structure, to grow, to live.
36:37Since the beginning of the universe
36:40there have been billions of stars.
36:44But ours has fed a real miracle.
36:50Life.
36:55That is why the sun
36:58is a more than extraordinary star.
37:08It is the only known star
37:11around which atom collections orbit.
37:14You and me.
37:17With the ability to give it a name, the sun, our sun.
37:20From the beginning of history
37:23we have venerated it and we have deified it
37:26to the point that it seems that the sun
37:29is at the base of all religions.
37:32In fact, there is a deep truth in that cult
37:35because our brief existence in the universe
37:38depends on that star.
37:42In fact, we owe it to all the stars.
37:45We do not need to invent imaginary gods
37:48to explain the universe.
37:51We can replace them for the authentic.
38:08All our loved ones.
38:15Everything we value.
38:20Our great achievements as a civilization.
38:29They have been created and elaborated
38:33by the stars.
38:56In our galaxy there are more than 200 billion stars.
39:03And there are two billion galaxies
39:06in the observable universe.
39:18We live in the era of the stars.
39:33An era of light and life in the cosmos.
39:42From our fleeting human perspective
39:45the stars seem eternal.
40:03But not even the gods are immortal.
40:12Where there is light
40:15there is also darkness.
40:23The stars are creators.
40:33But they can also be jealous guardians of their creations.
40:42Many small stars
40:45do not die with spectacular explosions
40:48but they fade away slowly.
40:56They become fossil stars.
41:03Preserving the valuable elements
41:06manufactured throughout their life.
41:09Those fossil stars
41:14remain inert in the universe.
41:21Depriving the future of the necessary material
41:24to create new generations of stars.
41:33The future of the stars
41:45The era of the stars seems infinite.
41:50But it had a beginning
41:53and it will have an end.
41:57Let's imagine the timeline of the universe.
42:00Here would be the origin of the universe
42:03the Big Bang
42:0613,800 million years ago.
42:09About 100 million years later
42:12the first stars were formed.
42:15On this scale, one centimeter is equivalent to 20 million years.
42:18At 4 million years the peak of star formation was reached.
42:21It is when the maximum number of new stars was born.
42:259 billion years later
42:28our sun was born.
42:31And today, after 13,800 million years
42:34it has reached half of its lifetime.
42:40Our sun will die within 5 billion years
42:43but new stars will be born
42:46and many of the oldest stars
42:49the smallest, will continue to shine.
42:53In fact, we think that the last star
42:56will cease to shine within 10 billion years
42:59and the universe will darken.
43:04On this scale
43:07we would have to place it
43:10about 5 kilometers from the Big Bang
43:13but that will not be the end of the universe
43:16as far as we know, it will continue to expand eternally.
43:19The light of the stars
43:22is the shortest moment in the infinite history of the universe.
43:25The age of darkness will continue, will continue, and will continue.
43:37The stars do not suddenly disappear, of course.
43:43They will remain here for eons.
43:49But, over time,
43:52the universe will become darker,
43:55colder, and emptier.
44:07Today, there are stars
44:10that already existed near the beginning of the era of the stars.
44:20And some of them
44:23will also be at the end.
44:30They are the longest stars in the universe.
44:35They are the red dwarfs.
44:45Trappist-1 is one of the oldest
44:48stars in the universe.
44:55It is more than 7 billion years old.
45:00It is almost twice the age of our sun.
45:12But it is a tenth of its size.
45:19And less than 1% of its luminosity.
45:27It is a cold star
45:30that burns very slowly.
45:38And that is the secret of its longevity.
45:42As they burn so slowly,
45:45the red dwarfs live a long time.
45:57Much longer than any other star.
46:06Like the sun,
46:09Trappist-1 has its own planets.
46:14They are seven rocky worlds,
46:18similar in size to those on Earth.
46:25Some of them have an atmosphere,
46:28and even seas.
46:40But that is where the similarities end.
46:55They are very strange worlds.
47:00Each of the seven planets
47:03is anchored in its orbit.
47:06One side is oriented towards Trappist-1.
47:10The other is frozen,
47:13permanently exposed to the cold emptiness of space.
47:29If we could be on the surface of one of those worlds,
47:37with the passage of time,
47:44we could see the slow development
47:47of the future of the cosmos.
48:00And one day,
48:03in five billion years,
48:09we would see how our sun
48:12blinks and fades forever.
48:34The death of our sun
48:37will probably go unnoticed.
48:41We won't be here to see it.
48:44Maybe some alien astronomer
48:47from a distant world,
48:50on the other side of the Milky Way,
48:53will see it with his telescope.
48:56But I don't think they'll give him any information.
48:59We've seen hundreds of stars die,
49:02and we haven't given him any information.
49:05But I think the death of our sun
49:08will be important here,
49:11in this little corner of the universe,
49:14because it will mark the end
49:17of a glorious era in the history of our galaxy,
49:20where the meaning of life existed.
49:23Science, literature, art, poetry, music,
49:26and that's important.
49:33And why does the meaning of life
49:36have to be eternal?
49:39It's the fragility of our lives
49:42that makes them so valuable.
49:45I think the wonderful thing is that our star
49:48has taken the laws of nature
49:51and has made a great materialization
49:54of them on this planet.
49:57You, me, and all this.
50:25Stars like TRAPPIST-1
50:28will continue to shine
50:31after the death of our sun.
50:39We'll never know the name
50:42of the last star.
50:54But we do know
50:57that the last shining star
51:00will be a red dwarf.
51:09The last star will slowly cool down
51:15and fade away.
51:25With its disappearance,
51:28the universe will become again
51:31an empty space,
51:34without light
51:37and without the meaning
51:40of life.
51:54The Last Star
52:11The stars have illuminated the universe
52:14and created the most intricate structures.
52:20And one day,
52:24the stars are gods,
52:27but they're mortal gods.
52:30And when that time comes,
52:33when the last stars fade away
52:36and all possibility of life
52:39in the universe disappears,
52:42they'll have left the most profound legacy.
52:45Because for a moment in the long history
52:48of the universe,
52:51they allowed us to illuminate it.
53:21We want to study the sun
53:24because it teaches us a lot
53:27about the stars.
53:30It teaches us a lot
53:33about the billions of stars
53:36in our galaxy and beyond.
53:46During the final assembly
53:49I took a moment to look at it
53:52and to realize that this is going to be a star.
53:55And I realized how special it is
53:58to be able to work on this
54:01and that humanity decided
54:04that this was something that had to be done.
54:07Minus 30.
54:09Proof of state.
54:11Go Delta.
54:13Go PSP.
54:15Minus 15.
54:17Four.
54:18Three.
54:19Two.
54:20One.
54:21Zero.
54:22Liftoff.
54:23Liftoff of the powerful Delta IV Heavy rocket
54:26with NASA's Parker Solar Probe on board.
54:29There we go.
54:31It's the first time that NASA has baptized a spacecraft
54:34with the name of a living person,
54:36and Eugene Parker is a fundamental physicist
54:39in our field.
54:41The Delta IV Heavy is a very slow rocket
54:44if you compare it to other launches.
54:46So I just saw the fireballs at first
54:48and I was very, very scared.
54:51Twenty-five seconds.
54:54The camera pressure is still good
54:56on all three propellers.
54:58Then realized that everything was going well
55:00and slowly, slowly, the rocket was going up into the sky.
55:04Fifty seconds.
55:07Parker Solar Probe is revolutionary
55:10because it's the first time that we're actually going to touch the sun.
55:14We're going 94% of the way between the earth and the sun
55:19to experience the solar crown, the atmosphere of the sun.
55:23I think that our closest approach
55:26is going to be eight solar radios from the sun itself.
55:29It's going to be the first time that we're actually going to touch the sun.
55:33It's going to be the first time that we're actually going to touch the sun.
55:36It's going to be the first time that we're actually going to touch the sun.
55:42So we were expecting everything to be very hot,
55:45over 1,300 degrees Fahrenheit,
55:48but in a plasma soup at more than half a million degrees.
55:55That's a real challenge,
55:57to get the probe to survive in that environment.
55:59It's a real challenge.
56:01Parker has a huge thermal shield in the front
56:04that protects the instruments installed in the main body.
56:10What makes the probe so special
56:13is that it has a set of instruments
56:16that work together, observing in all directions,
56:19to solve the great mysteries of the solar wind.
56:22The solar crown has always been a mystery.
56:25It's really strange.
56:28The surface of the sun is at about 3,500 degrees.
56:31And above that, you have this thin atmosphere
56:34that's at about half a million degrees.
56:37And the way it heats up,
56:40we know it's something to do with the magnetic fields,
56:43but we don't know exactly how it works.
56:46That's where the solar wind is generated.
56:49And we don't know exactly how it works.
56:52We're also learning about the mass ejections.
56:55When we were initially planning,
56:58we thought we wouldn't see more than five
57:01in the seven years that the mission lasts.
57:04And we ended up seeing four or five
57:07just in the first year.
57:10So, there's been a significant change
57:13in the way that the mission works.
57:16So, there's been a significant change
57:19in the activity of the sun
57:22or in the mass ejections of the crown.
57:25Maybe there's changes in both.
57:32It is a pleasure to see all of that data coming in.
57:35It's a pleasure to share it with everyone
57:38who has had the same curiosity
57:41that I have had for a decade.
57:45So, Parker probe has just begun its mission,
57:48but it's already transforming our understanding
57:51of how the sun works.
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