4 Ways the Universe Might End (All of Them Are Bad)

hey smart people joe here now i don't want to alarm you but the world is going to end all of this gone poof adios the sun swells into a red giant the oceans boil away planet scorched and scientists are certain that all this will happen now i'm sorry if you're just hearing this from me but i want you to know the truth now on the bright side this isn't gonna happen for four to five billion years in a universe bigger than we can fathom across eons of time stars like the sun and planets like earth they blink out of existence all the time but could all of it end i mean everything the whole universe yes and it probably will [Music] i've been thinking about the end of the universe a lot lately and i know what you're thinking hey joe you okay kovid finally getting to you and don't worry that's not why it's because i've been reading this awesome book the end of everything astrophysically speaking by my friend astrophysicist katie mack it is great and i have never had more fun learning about how everything will cease to be forever the big crunch this is andromeda a trillion stars whizzing around a super massive black hole and the milky way's closest galactic neighbor and it's headed this way right now andromeda is currently around two and a half million light years from earth but it is closing that distance at 110 kilometers per second on a crash course with our galaxy in about four billion years the galaxies will start to merge into one across the cosmos galaxies collide on a regular basis and we can see these collisions with powerful telescopes even simulate these collisions on really really really big computers that go beep boop and do hard math stuff but these galactic mergers are becoming more rare because giant stuff like galaxies are drifting farther apart i don't know maybe they should check in once in a while just send a text it's not that hard you set up a coffee date catch up on old times actually galaxies are drifting apart because the universe is expanding and that expansion all started with one big push the big bang think of the universe like this slinky it started here and since that push the space between each rung of the spring has been getting slightly bigger that's like neighboring galaxies and as a result the ends have gotten way farther apart because of the collective distance between all these small expansions happening within its boundaries all that started with the big bang the question is will that initial push from the big bang eventually fizzle out think about it thanks to gravity everything is always attracting everything else that's why andromeda and the milky way will one day collide now the farther apart two objects are the gravitational attraction between them does get weaker but it never reaches zero it seems like the gravity of everything in the universe should eventually pull it back in so what happens if that expansion stops and goes in reverse doom in a collapsing universe the space between galaxies would get smaller and smaller collisions would become more frequent stars and planets flung out of orbit black holes ignite and merge becoming even more massive matter whirling into these giant black holes is superheated by friction so hot that it shoots out jets of radiation scorching anything in their path imagine rubbing two sticks together so hard that the fire that they create emits x-rays it's like that during these galactic crashes some new stars will be born even new planets and some of them might even have time to develop life if they're not the path of a sterilizing x-ray beam but eventually all of these two will be destroyed by fire as the universe collapses all of the energy that's ever been emitted by every star or drawn into any black hole will be squished into a smaller space and squeezed into higher energy wavelengths this concentrated radiation will become so intense the temperature of space will rise until nuclear explosions rip stars and planets apart leaving space full of hot plasma at this point the universe resembles the early moments after the big bang the temperatures and densities are so high we don't actually have a way to describe them except really really really hot that's three rillies so you know it's bad but what if that crunch never happens well today we think the universe isn't likely to snap back on itself but turns out that's not such good news either [Music] when you throw a ball into the air it slows down and falls back down okay everybody knows that but in the early days of the universe things were close together and so gravitational attraction slowed the outward push of the expansion from the big bang and expansion was slowing down just like a falling ball for a while but in 1998 scientists discovered about five billion years ago the expansion of the universe started speeding up and it's still speeding up like what would happen if you threw a ball up in the air and it kept going faster in the same direction forever and the bigger our universe gets the faster it's expanding that's weird really really really weird and it's three really so you know it's weird there's some mysterious property of empty space pushing outwards in all directions and we call this dark energy the more empty space there is the more dark energy and the more it pushes dark energy might be a source of energy that never runs out and that we find everywhere there's empty space something that astrophysicists and cosmologists call a cosmological constant and as the universe expands it makes more empty space which means more dark energy and the expansion gets faster and faster on the nearby scale other forces like gravity and electromagnetism are still strong enough to keep molecules together your feet on the ground our planet orbiting the sun and our galaxy from falling apart but the vast spaces between galaxies are dominated by dark energy the universe is already expanding faster than the speed of light meaning that light emitted from galaxies beyond this point will always be moving away from us and will never reach earth and as that expansion speeds up closer and closer galaxies will be outrun and they'll disappear from our view eventually every galaxy will be alone in a dark universe nothing will approach anything else the stars already shining will burn out over billions of years 100 billion years from now the milky way will dim and eventually fade to black even black holes will evaporate there's no fuel for new stars just vast empty spaces left filled only with dark energy expanding forever a slow death by loneliness lasting hundreds of billions of years it could be worse though if dark energy actually gets more powerful over time that that would that would be so bad [Music] meet phantom dark energy it's like dark energy on steroids phantom dark energy would not only expand the space between things but expand things themselves remember in our universe today fundamental forces are enough to hold things together even as dark energy expands the universe as a whole but phantom dark energy would be strong enough to overcome all of those other forces it wouldn't just push galaxies apart it would push stars away from galaxies planets away from stars tear planets apart eventually atoms and molecules and particles would rip apart as phantom dark energy becomes stronger than the electromagnetic forces that hold them together and in the final moments the very fabric of space would be torn apart a big rip but don't worry if the big rip is coming it's not coming for like 200 billion years so at this point it might be nice to remind ourselves that both you and i will be dead by then so hooray but there's one scenario that might be less far off it could happen any time it could be happening right now but it destroys everything so fast you wouldn't feel it it all starts with a bubble it's like a self-destruct button for the universe setting off a wave of apocalypse moving at the speed of light how could that happen something called vacuum decay now the higgs field is a sort of energy field it permeates all of space it surrounds us and penetrates us it binds the galaxy together the higgs field sets the rules for physics on the scale of particles like what particles exist how they interact with each other what their masses are atoms and molecules and trees of people and planets for that matter are only able to hold themselves together and exist because the higgs field has a particular value if that value were slightly different it could scramble all of that up in fact it was like this in the early universe the higgs field had a different value and there were different particles with different rules the higgs field is pretty stable it's settled down here at a low energy but there is a small chance that an ultra high energy explosion the evaporation of a black hole or a quantum event could kick the higgs field to some lower value this would create a sort of bubble in the higgs field a new kind of space with different rules and this bubble would zip through the universe at the speed of light ripping particles apart swallowing everything in the bubble if it hit you you'd be gone before your brain knew anything happened once this bubble destroys everything the space inside it collapses into a black hole and they all lived happily never after don't worry there's no way that we could trigger vacuum decay ourselves but the universe might don't lose hope though we have one more scenario what if the end isn't the end there is another option other more recent theories point to cycling universes where the end of one is the beginning of another these theories involve ideas like anti-universes or parallel fabrics of space-time but they would mean that an end really isn't an end at all as we learn more all of these theories may change and we may even find some new ones but understanding our universe so deeply that we could one day figure out its ultimate fate as well as ours well that's a nice way to add meaning to a universe that we know won't last forever and besides none of this will happen for a very long time like at least tens of billions of years maybe more than a hundred billion i guess unless it's vacuumed stay curious hey everyone are you feeling a little stuck inside then you should check out overview it's a brand new show on pbs digital studios science and nature channel tara overview combines mesmerizing beautiful drone footage with deep science storytelling to reveal all the things that shape our planet from a bird's bird's-eye view literally go over to tara subscribe and oh did i mention that i'm the narrator yeah you get to hear me tell you these stories get over there already subscribe go watch them what are you still doing here i want to say a huge thank you to my friend katie mack this really is a great book she helped make this video possible there's links down in the description if you'd like to learn more about her awesome astrophysics work and as always i'd like to say a huge thank you to everyone who supports the show on patreon your support means everything to us it helps us make these videos and add a little bit of meaning to this universe that we know won't last forever there's links down in the description if you'd like to join our community see you next time the big crunch [Music] you ready the big crunch the big crunch

Channel: Be Smart

Views: 1,167,879

Keywords: science, pbs digital studios, pbs, joe hanson, it's okay to be smart, its okay to be smart, it's ok to be smart, its ok to be smart, end of the universe, big rip, big crunch, physics, cosmology, astrophysics

Id: 8uQgiv_Uy7w

Length: 12min 58sec (778 seconds)

Published: Tue Oct 13 2020