The Universe: Dark Future of the Sun (S5, E8) | Full Episode | History

in the beginning there was darkness and then  bang giving birth to an endless expanding   existence of time space and matter every day  new discoveries are unlocking the mysterious   the mind-blowing the deadly secrets of a place  we call the universe it's the apocalyptic finale   of our galactic neighborhood  probably the most dramatic event   in the entire history of the solar  system we've now uncovered sizzling   clues about our home star's violent demise and  the outcome doesn't look good for planet earth you could experience both death  by fire and also death by ice new cutting edge science traces the  real horrors awaiting our planet   as our sun unleashes its final fury  the kiss of death for everything our sun it's bathed us with light  and energy for over 4.5 billion years   but like all things in the cosmos our  nurturing star will eventually die and earth could literally melt into the sunset when the sun gets a hundred times  brighter than it is now the entire   surface of the earth will be incinerated  all the rock that composes the continents   will melt and run into seas of molten  lava the earth will be uninhabitable the death of our sun will have a  profound effect on our cosmic world   we rely on our home star located  in the center of our solar system over 1 million earths could easily fit  inside this gargantuan ball of bubbling gas   with core temperatures reaching  30 million degrees fahrenheit the sun is approximately 93 million miles  away so earth is not too hot or too cold   it's the perfect distance to sustain  oceans of liquid water and abundant life we're incredibly dependent on the sun's energy  for our survival first and foremost plants utilize   solar energy in photosynthesis so that they can  grow and then we use plants for food and so do   other animals and we eat those other animals  we also use the fossil fuels from partially   decayed plants winds are also generated by the  sun's heat we're using solar energy everywhere all this life-giving heat and  light comes from the sun's core a colossal nuclear reactor comprised  of three-quarters hydrogen and the   rest mostly helium with traces of heavier elements here hydrogen nuclei combine to  form helium nuclei this process   called fusion gives off radiant energy this car is like a newly formed star like the sun when a star like the sun is born it's born with a  full tank of gas so if i fill this tank with gas that's like the hydrogen coming together  gravitationally forming a hot dense core that   gas will later burn in the case of a star hydrogen  will fuse to form helium giving the star energy   just as in the case of the gas burning in the car  that'll give the car energy with which to move like an automobile the sun  will eventually run out of fuel and earth will be without  this crucial power source   the rate at which it's fusing hydrogen into helium  it will someday simply run out of hydrogen in its   core we can see other similar stars that were born  much earlier than the sun and they're now dying to track our sun's dark future we  travel back in time to its beginning these exotic clouds of gas  and dust are called nebulas they consist of the remnants of dying stars but upon closer observation they're actually   stellar nurseries where  stars like our sun were born about four and a half billion years ago  in our galaxy a giant cloud of gas and   dust gradually was pulled together by gravity  and as gravity caused that cloud to collapse   a lot of energy was released it heated  up and finally in the center nuclear   reactions started changing hydrogen  into helium and a new star was born the remaining stellar material  swirled around the newborn sun   it collided and coalesced eventually sculpting the  eight planets in our solar system including earth when that happened a stellar wind turned on  and cleared out all the extra material leaving   the planets that we have today and additional  bodies some of which collided or merged with   the other planets among the billions of points of  light in the universe our sun is an average star   there are stars one hundred times its  mass and contrary to its appearance the   true color of the sun differs from  what we see when it rises and sets the sun is actually a white star not a  yellow star it's white like this car now it's   true that the peak of its spectrum  is sort of in the yellow region   but it also emits some blue light and green light  orange and red and all those colors together   are perceived by our retina and  our brain as the color white our sun has a lot in common with humans   when it was young it was extremely  active and often unpredictable what we found was really very surprising we  found that stars like the sun when they're   very young are rotating much much faster than  today if you can imagine something as big as   the sun just whipping around uh in one day or  even less that was a very different kind of sun   was having all kinds of eruptions that blasted  particles through space that hit the earth right now our sun is middle age and has  settled into a quieter regular schedule   but it's still generating a lot of energy the  sun right now is about four and a half billion   years old it's slightly under half of its total  anticipated lifetime so it's kind of like this   car with a little bit more than half  of its tank still full the sun now   is burning fuel that is fusing hydrogen to  helium at a steady but ferocious rate it's   like a 90 billion megaton bomb going off every  second it's just an incredible amount of power on earth we're actually only receiving about  one two billionth of the energy that's being   produced at the sun now on a daily basis that's  enough energy to power about 29 million billion   100 watt light bulbs for one hour the amount of  energy being generated in the interior of the sun   is just enormous our sun will continue to  churn out energy over its entire lifetime   which is estimated to be around 12 billion years  in the 1990s scientists confirmed its age and   when it will die by measuring its brightness and  original mass as well as analyzing its sound waves   light doesn't penetrate the sun it's opaque it  sounds strange because light comes from the sun   but light can't pass through it so until  recently there was no way to probe the   deep interior of the sun there's a science now  called helioseismology that uses sound waves   to actually probe the interior  structure of the sun and so we have   a very good knowledge of what the  interior structure of the star looks like   and that's allowed us to constrain and confirm  the models of the sun's age and its evolution strangely our sun is now 30 percent brighter than  it was at birth as it ages it will gradually grow   even brighter and more powerful our climate is  very sensitive to the energy from the sun so if   you're worried about global warming you worry  about what humans are doing to the atmosphere   but you also need to know what the sun is doing  to the atmosphere the most recent estimate says   that maybe 20 percent of all the warming that's  happening the global warming is due to the sun in one billion years our star's luminosity   will be 10 percent greater and temperatures  on our planet will be 100 degrees hotter   the moisture in the air is very good at trapping  infrared radiation or heat and so it's sort of   like putting a blanket on the earth now  here's the bad part as the earth warms up   the oceans evaporate even more we trap  more heat and so the earth warms up more   and when the earth warms up more  again we trap even more heat   and the effect can run away it's  what we call the greenhouse effect with this surge of heat due to the runaway  greenhouse effect life on earth will be in peril whole societies will need to retreat  to underground shelters during the day   then emerge at night when  the temperature cools down   but as the thermometer continues to climb  there eventually will be nowhere to run or hide we know how that story ends it's called the  planet venus if you think about it venus is   only about 30 percent closer to the sun than the  earth is but it's way way way hotter 800 degrees   we don't quite have the technology that would  allow us to survive on the surface of venus but   we could imagine what would be required insulating  yourself from the heat so it would be a challenge in 3 billion years our sun's  brightness will increase   40 percent by this time  oceans will have boiled off earth will have become a global desert the sun will have used up about three quarters of  the hydrogen in its core fused to helium like this   car is three quarters empty by this time the  sun will be brighter than it is now and bigger   so earth will be hotter it won't be  a nice place to live at that time and the solar nightmare is far from over as the sun nears its 10 billionth birthday  and beyond the most drastic changes will occur if human type civilizations are still around what  will be the options for survival when our sun   eventually fills the entire horizon  it's a foregone conclusion when the sun   is about 10 billion years old it will  run out of hydrogen fuel in its core   it's the beginning of the end for  our star and it won't die peacefully as for earth global warming or other cataclysms could snuff out every living  thing in a mere 1 billion years   but if human descendants somehow managed to  survive until then they could face a living hell   when the sun burns through all  of its hydrogen at its core it will eventually start contracting  on itself because it's no longer   burning through the hydrogen fusing  it together creating this radiation   pressure outwards to balance  the gravitational pull inwards while hydrogen fusion will stop in the core  it will continue to fuse at a faster rate   in the shell surrounding the core the extra  energy will expand the outer layers of the sun that'll mean that the sun will grow much more  powerful much more luminous because the hydrogen   shell will be fusing while the core is contracting  at a greater rate than it normally would   all the pressure from the energy  generated in this hydrogen-fusing   shell will cause the outer parts of the  sun to expand making it into a red giant a red giant is a star that has exhausted the  primary reservoir of hydrogen fuel at its core   leaving behind a build up of the heavier denser  helium an average sized star like our sun   will spend the final two billion  years of its life as a red giant   we call it a red giant because as this  expansion happens the surface area gets   so great that it actually cools off and in terms  of temperature stars that are cooler appear redder during the initial red giant phase catastrophic  changes will occur our sun will swell   to 20 to 30 times its original size  and become 100 times more luminous as our red giant sun expands   it will continue to vigorously fuse hydrogen in  the shell surrounding the inactive helium core thus producing more helium in the core as that  happens the core of the sun collapses further   and gets hotter and the sun gradually expands  over the course of a couple of billion years   eventually the core of the sun is hot enough  to ignite the helium you get what's called a   helium flash it's like the stellar equivalent  of the big wolf when you light a gas barbecue the ignited helium will be hot enough to  undergo fusion now creating carbon and oxygen   in the core the dying sun will be resuscitated  with this new but temporary form of energy i'm stuck here in the  desert and i've run out of gas   but you know i have a spare gallon here  in the trunk and if i pour this gas   into the gas tank that'll allow the  car to keep going for a while longer   this is kind of similar to the sun during the red  giant stage it's going to run out of hydrogen as   fuel but it'll have helium that can briefly for  a few tens of millions of years fused to carbon   and oxygen providing a new source of energy  that'll keep the sun going for a while longer at the end of the initial red giant phase the  dying sun will enter this stable helium burning   phase it'll become hotter yet somewhat smaller  but this is merely a lull before the storm this is because the sun's transition to  a red giant actually comes in two phases during the second phase the helium will be  exhausted in the core which will now consist   of carbon and oxygen the core will again start to  contract and heat up but helium will still exist   in the shell and it will continue to fuse forming  more carbon and oxygen in the contracting core   and all of this will be surrounded by the hydrogen  shell that's still fusing to helium when the sun   becomes a red giant it will expand out and the  first thing it'll do is engulf the planet mercury   and eventually incinerate it evaporate it  eat it up then it'll expand out to venus after the helium changing into carbon  uses up all of its energy then the core   begins to shrink a second time the outer part  expands a second time and it's not very stable during the second red giant phase the wild  contraction and expansion will make our sun   pulsate like a slow beating heart the pulsations  can occur every few hundred or thousand years   and with each pulsation  planetary pandemonium will ensue mercury and venus are doomed  they'll be engulfed by the red giant   however there's been some debate in the  scientific literature as to whether the   earth would actually be engulfed or not the  sun will be large enough to engulf the earth   earth's future is uncertain because it lies on the  border line between being engulfed and surviving but astronomers now have one possible  sneak preview of our planet's ultimate fate   the infrared optical telescope array has captured  close-up photos of a death star kai signi which   is approximately 50 light years from earth kai  signi is near the end of its red giant stage   when it's grown really big and in those last few  million years of existence it starts pulsating it   actually pulsates every 400 years or so getting  bigger and brighter and smaller and fainter if the massively bloated  star kai signing were our son   it would have consumed every planet out  to mars earth and all its wondrous forms   of life would have been melded with  the materials inside the dying star we obviously haven't been around  long enough and will not be in our   lifetimes to understand exactly what's  going to happen when the sun dies   so we need to look to other stars  in order to see how that might work observations of other death stars have offered  a startling glimpse at our own sun's long-term   prognosis and what's in store for the rest of the  solar system earth could be catapulted into the   fiery abyss however recent research indicates  that with the right set of cosmic conditions   a shockingly different fate may  await our fragile planet all things   must end in about five billion years our motherly  son will stop nurturing its planetary offspring as it begins an agonizing death march   it will expand 100 fold and devour  the planet's mercury and then venus near the end of its second red giant  phase the sun will contract and expand   several times with each pulsation our dying star  will become dangerously close to swallowing earth however with the right set of  circumstances our planet could be spared   there's a phenomenon called the solar wind that's  continuously blowing lifting material from the   outer layers of the sun's atmosphere out into  interstellar space when the sun begins to expand   into the red giant phase the outer  layers of its atmosphere are even   more loosely bound than they are now  and so the solar wind will be much more prominent the data indicate that if the solar  wind blows off about 30 of the sun's mass its   gravitational pull will weaken enough to  allow earth to move sufficiently outward   if the sun loses some of its  mass its gravity gets weaker   and the earth's orbit is going  to get bigger so if we're lucky   our orbit will expand out enough that it will miss  the expanding sun and we won't get incinerated   but earth won't be completely removed from  harm's way while the sun might lose mass   it could also have a tidal interaction with our  planet and this could have sizzling consequences there are at least two competing effects although  as the sun ages it's losing mass and that means   that earth's orbit gradually drifts away from the  sun it's also true that earth being pretty close   to the surface of the sun will raise a tide  a bulge of gas on the sun and a gravitational   interaction between that bulge and the earth  will actually slow down the earth in its orbit   causing the earth to gradually spiral in so maybe  the loss of mass will move us out enough to be   safe but maybe the tidal forces will spiral us in  enough that will be engulfed and the earth will   be incinerated and if you come back in five or  six billion years you'll know which one wins out   earth just might get lucky an  international team of astronomers   discovered a planet outside our solar system  that survived the death of its home star the exoplanet is at least three  times as massive as jupiter   and orbits the star dub 391 pegasi  which is about the same mass as our sun some exoplanets clearly do survive through the  red giant stage for example 391 pegasi is a   star that has an exoplanet around it a planet  orbiting it and that planet is is still there   now it might have a rocky earth-like core  and perhaps even an iron central region   but we think it's mostly gaseous and liquid 391  pegasi and its gas giant planet have a similar   orbital distance from each other as earth does  from our sun which is about 90 million miles astronomers think the exoplanet survived  because its death star lost mass which   reduced its gravitational pull on the planet  just enough so that it drifted slightly outward   the planet around 391 pagassi is likely to be  one of these planets that have sort of walked   the knife edge between spiraling outwards and  being dragged in by tides you would not expect   to find a lot of planets in that particular range  of distances you would expect them to either be   completely swallowed or have them be much further  out and so it requires a somewhat delicate balance   of the two competing forces to actually enable  a planet to survive at that sort of location   so there's one case in which the planet survived   the bad news is that in this solar system the  planet is really big larger than jupiter and so   it probably has a better chance of surviving  than a small planet like the earth would it appears that stellar winds and  thermal pulsations produced by 391   pegasi pulled atmospheric material from the outer  layers of the exoplanet and hurled it into space   however the gas giant planet survived  because it could afford to lose a lot of mass   we can speculate that it may have  lost one or more earth masses of   material and of course if the earth lost  that much material it wouldn't be here   certainly a jupiter-sized planet a gas giant  isn't inhabitable by people but it's still   intriguing that if the sun went to the red giant  phase it's possible that jupiter would survive the continued existence of the gas giant planet  orbiting 391 pegasi doesn't provide conclusive   evidence one way or the other whether  earth will survive the death of our sun but one thing seems certain long before our  sun becomes a red giant our planet will no   longer be hospitable for earth-type life any  future civilizations will need to relocate   and billions of years before the impending inferno about a billion years from now if viewers were  around i'd recommend that you move to mars   mars instead of being too cool like it is now  would probably have a somewhat more favorable   temperature if there is water underground in  mars and we don't really know one way or the   other for certain yet maybe you could use some  of that water and you might have a comfortable   retirement on the planet mars but the move  to mars wouldn't be simple the red planet   would be warmer than it is today but it would  still be missing a few of life's necessities you have to create an atmosphere you have to  have pretty high pressures in order to have   molten water on the surface you need to somehow  generate oxygen just because a planet or a moon   is in the habitable zone doesn't  mean that it's already habitable if you were a strategic planner you would  encourage the growth of plant life on mars   a billion years in the future you would  generate oxygen and you'd make that planet   more hospitable for us perhaps a little  egotistically we call that terraforming   that we could form another planet in the shape of  terra or the earth i hope we're here to do that   even if an advanced society manages to colonize  mars this new home will be temporary the sun   will continue to become brighter and bigger  pushing the habitable zone even farther out during the red giant phase earthlings will  have to move again perhaps to the water-rich   moons of jupiter or saturn but with every  new location there will be more obstacles near the end of the sun's red giant stage it will  rapidly be growing much brighter and much bigger   so we'll need to move to the new habitable zone  much more frequently another problem with moving   to a new planet or a moon is that it would be  very difficult and expensive to move all humans   so whom do you choose just some elite subset  of society that would create great problems   instead of abandoning earth  before the sun becomes a red giant   another alternative might be to actually move the  entire planet this may sound like science fiction   but technologies are already being considered  that might rescue earth from the solar apocalypse predictions about our son's demise are widely  accepted in about five billion years our star will   begin a long violent death as it mushrooms into a  red giant it will vaporize planets mercury venus   and most likely earth if human type  civilizations still exist they will have   already relocated to the outer solar system and  they may have even hauled earth away with them   the challenge will be finding the right cosmic  moving van we might gradually move the earth   to a new habitable zone by for example taking an  asteroid and bringing it into an orbit so that it   comes reasonably close to the earth every once in  a while and gives it a gravitational tug outward right now scientists are running  computer simulations to test   the feasibility of actually moving  earth using manned or drone rockets in order to do that we would either have  to use solar sails perhaps to direct this   asteroid into the correct place or maybe  a fusion powered rocket in a billion years   we may have other technologies that you know are  much easier and who knows what we can do by then researchers have determined that an  asteroid would need to be rounded up   every 6 000 years to keep nudging our planet  outward as our sun grows in brightness   if it does that very gradually very  steadily but over millions of years   then we will gradually drift out keeping  pace with the drifting habitable zone even if earth could be reorbited beyond  the danger zone its future remains bleak   near the end of the second red giant phase the  unstable pulsations of our sun will subside   because much of its outer  atmosphere will be ejecting away however this means its energy  will be rapidly depleting   there won't be as much mass  as much gravity pushing down   on the thin helium layer and compressing it  and it won't be as sensitive to the temperature   at this stage the sun will actually become smaller  and hotter and bluer not red and big and extended and so the nuclear reaction rates  are going down so eventually   when the star has lost enough mass those  reaction rates basically die away so the   star in this case the sun will eventually  run out of fuel and it will start to shrink unlike other stars our dying  sun will not go out with a bang   when it runs out of fuel some death stars  actually produce a supernova explosion   a burst of radiation that can  temporarily outshine an entire galaxy but why won't our sun have a spectacular fireworks  display upon its death that's what one viewer   wanted to ask the universe so leroy g from newport  rhode island texted us why won't our son go   supernova when it dies leroy i'm sure glad  the sun won't explode as a supernova there's   two reasons first the sun isn't massive enough to  explode on its own stars have to be eight or ten   times the mass of the sun to explode on their own  and second the sun doesn't have a companion star   from which it could steal material grow in  mass and eventually become unstable and explode at the last stage of our sun's  life its outer atmosphere   a glowing sphere of gas called a planetary  nebula will have drifted away all that will   remain of our once powerful star will be a  glowing white hot cinder called a white dwarf it'll be about the size of the earth at that point  and it'll have about half of its mass remaining   that object still has as much thermal energy  as the entire sun did but it's very small   and doesn't radiate it very effectively  white dwarfs are small but extremely dense   imagine our white dwarf sun as small as the  earth but with the same mass as a whole star   if you were to take a chunk of white dwarf  material the same size as the cell phone   it would weigh approximately the same as  an elephant so it's very dense material   although this white dwarf size is very  small relative to the sun as we know it today as a white dwarf our  sun will slip into retirement   using up its life savings of thermal  energy for billions even trillions of years   when it has become a white dwarf it'll be like  a car that's coasting it's run out of gas but   it's still moving because it has energy of motion  that's propelling it forward it's not generating   any new energy by burning fuel it'll be radiating  away the stored energy in its hot interior energy   that it had generated through nuclear reactions  when it was young and vibrant so it's like a car   that's just going along without any fuel until  finally eventually very slowly it comes to a halt anything left in the solar system after  that transition to the white dwarf stage   would just gradually cool off it would remain  in orbit around the white dwarf the orbital   decay times are extremely long and it would just  stay there as a quiet cold orbiting body forever our white dwarf sun will become  progressively cooler and dimmer since   it's no longer generating energy everything  in the solar system will begin to freeze as the sun's vital signs continue to  dim what will be the forecast for earth in its death throws our aging sun will  become insufferably hot as a red giant   and then unbearably cold as a white dwarf this could be the kiss of death for planet earth  as it moves from the frying pan and into the frost by the time the sun becomes a white dwarf we can  imagine that temperatures on earth depending on   where it is in its orbit would drop significantly  fairly rapidly because the white dwarf is no   longer producing energy through fusion so it's  not producing this energy to heat the earth we'll be fried to a crisp if we remain where  we are during the red giant stage but in a   similar vein we will go into a deep freeze if  we remain where we are when the sun becomes a   white dwarf nevertheless there will be some  pockets where life could continue to survive   for example in the liquid parts  deep in the oceans it could survive   at the outset humans could theoretically  live in submarines near hot hydrothermal   vents while they dredge up the geothermal  energy from deep within the earth's core   but after a million years the oceans would  completely freeze and life would inevitably perish after the sun becomes a white dwarf it's just  gonna cool and cool it's very much like a pot   on the stove once you turn off the burner there's  no more source of energy and so it just gradually   gets cooler and cooler and cooler if the earth  manages to survive until the sun is only a white   dwarf star it will hardly be getting any energy at  all i can say with absolute certainty that if you   stick around long enough you could experience  both death by fire and also death by ice without energy from our sun all remaining  life in our solar system will disappear however this disaster could be preempted  by accomplishing what so far has been   impossible to do actually duplicating the  sun's hydrogen fusion right here on earth science has already been able  to manufacture nuclear fission   which involves the splitting of  atoms into lighter smaller nuclei this is the power that drives our nuclear  power plants and ignites nuclear weapons   but nuclear fusion which occurs in the core  of the sun requires putting nuclei together to   form a larger heavier nucleus and so far this  process has not been achieved here on earth the problem with recreating the sun's conditions  is essentially getting materials to the densities   and temperatures that you have in the  center of the sun the sun has its gravity   to drive the pressures and dead seas up so you  can get these high reactions on earth we don't   have the luxury of using the sun's gravity so  we have to find other ways to try and compress   the material and generate the kinds of densities  that you see at the lawrence livermore national   laboratory in northern california scientists are  taking on the challenge by attempting to create   a miniature man-made star the experiment  involves aiming the world's largest laser   the size of three football fields at a  bb sized target filled with hydrogen fuel in an inertial confinement experiment like the  one at lawrence livermore you start with a small   pellet maybe a half an inch across the core of  which is made of a solid material containing   lots of hydrogen to undergo fusion the outside of  which has layers of different material that are   engineered to produce a shock wave that will drive  in and compress that core as much as possible the colossal laser will split into 192  separate beams that will strike the pellet   housed inside a capsule when the fuel pellet's  shell is struck by these high-energy x-rays   it should implode and then ultimately  produce nuclear fusion in its core if we had controlled affordable nuclear  fusion it would change everything   many things about our lives  would change but most importantly   we wouldn't need the sun anymore we could  produce energy heat light on demand we could   live anywhere in the cosmos with a supply  of hydrogen and make our own energy we could fly to other planets very quickly  in days instead of years you can extract   all the water you need from practically  any material that contains hydrogen oxygen   if there isn't enough oxygen  around you could make some generating reliable nuclear fusion could  ultimately save earth and all forms of life   by eliminating our dependence on the sun yet the sun's own fate is forever sealed as a  white dwarf it will become dimmer and cooler the star that once provided energy to an entire  solar system will eventually fade from sight   when the sun eventually cools off so much you  won't even be able to see it with your eyes   and so that's why some people call it a black  dwarf or a dark star it'll just be invisible   sitting there in space nearly forever our solar system cannot dodge its  date with doom in 5 billion years   but the death of one planetary system can  spark the birth of another our sun's nebula   will eventually blend together with other stellar  material and spawn the next generation of stars and one might even nurture  another vibrant planet like earth you

Channel: HISTORY

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Keywords: history, history channel, history shows, history channel shows, the universe, history the universe, the universe show, the universe full episodes, the universe clips, full episodes, the universe season 5 episode 8, the universe s5 e8, the universe s05 e08, the universe 5X8, watch the universe, Watch the universe full episodes, Season 5, history clips, history channel full episodes, universe, the universe season 5, Dark Future of the Sun, five billion years, Episode 8

Id: Y57571w4Uxg

Length: 44min 22sec (2662 seconds)

Published: Mon Jan 18 2021