Every Space Object Death Explained In 18 Minutes

[00:00:00]You wake up and immediately begin scrolling, just to discover a video on the full life cycle of fire ants. How informative. It's a good thing they die after 6 months though.

[00:00:09]Good morning, Kyle. I couldn't help but hear what you were watching while peeping through the keyhole. It makes you wonder though, doesn't it? How long would it take every object in the universe to vanish without a trace?

[00:00:22]People always ask how the universe will end, but nobody asks how every lonely rock, pathetic planet, and insane star will live and die. And yes, each one has a radically different fate than you think. Do you know all of them? Does the viewer? Good thing I've brought this literal map of life and death in the universe for us to find out on this beautiful morning. Chapter 1. Don't worry, we'll 100% cover the full life cycle of stars and extreme objects, but to fully understand that, we have to start with the rocky like short-period comets.

[00:00:55]See, these are just giant rocky ice balls. The exact second one loops within 6 AU of the sun, the solar radiation violently boils away 1 to 3 m of surface ice and dust, bleeding out up to half a percent of its entire mass every single orbit. Within 100,000 to 200,000 years, it literally dissolves into a vapor. And yes, that is the story of Halley's Comet that orbits past the Earth every 76 years. One day, it just won't. Aw, Kyle, it's okay, don't cry. It will have lived a full life, like my new hamster. The last one Yeah. Anyway, next up are asteroids. You think asteroids are indestructible? Wrong. Small ones like Bennu are just loose boulders barely glued together by microgravity. One decent impact and they will shatter into pieces, but the big ones will honestly fly around for literally ever unless they end up in a situation like a moon, which have two major ways they can die other than being roasted by stars.

[00:01:56]The first way is a death spiral by being too close to a planet. Of course, the example is Mars' moon Phobos, which orbits at around 9,400 km in just 7 hours and 39 minutes, which is how long I last riding a mechanical bull on Friday nights. My girlfriend always enjoys my stamina. But because Mars takes 24 hours to rotate, this speed gap drags the moon inward by 2 m every single century. That doesn't sound like a lot, but in about 70 million years, it will hit the Roche limit threshold, meaning at about 5,500 km from the center of Mars, Phobos gets violently shredded into a temporary ring of rocky garbage for 10,000 years before crashing straight into the atmosphere.

[00:02:40]Well, whatever atmosphere it has left.

[00:02:42]And the same can happen to almost any rock in a similar situation. The alternative are slow-orbiting moons like the moon, which because of Earth's ocean tidal forces is leaving us at 3.78 cm a year.

[00:02:56]In 50 billion years, if we don't all get roasted by the dying sun first, it'll reach a distance of 550,000 km from Earth and our day will be 47 hours long. Now, for some rocks, they might get to fly off into space, but for moons like ours, the dead sun's gravity, which we'll talk about in another chapter, Kyle, pulls a complete U-turn, forcing the moon into a multi-hundred billion-year inward spiral. Yes, it will eventually pass Earth's Roche limit just like Phobos. Damn, Kyle, even if we all survive that long, eventually the moon will probably just crash and kill us.

[00:03:32]These poor rocks. Well, at least it's a lot easier than being a planet. Well, until you die. Chapter two.

[00:03:40]What's that, Kyle? All planets eventually get obliterated by a star?

[00:03:44]Nah, most planets die long before that happens. Think of a planet as an engine powered by a hot, churning liquid iron core that generates an invisible magnetic shield because that's what many are. But if a planet is too small, it leaks its internal heat into space at a blistering rate. The exact second that core freezes solid, the magnetic shield drops to zero and the solar wind slams directly into the surface stripping the atmosphere and boiling the oceans until all that's left is a dead frozen skeleton like Mars. Though what about Earth? Yeah, our core is freezing by 1 mm a year. In a few billion years, same thing. Atmosphere dies, magnetic shield won't exist, and we're bone dry as a desert corpse. We die before the sun even expands. Merry Christmas, huh? Then there are planets like WASP-12b that get murdered from day one. Orbiting at just 0.08 AU, its entire gas atmosphere's bleeding into the star 10 to the 10 kg a second. It's leaking worse than my waterbed after cheat day.

[00:04:47]After a few hundred million years, all that's left is the dead roasted core.

[00:04:52]What's called a thonian planet, like a roasted marshmallow for stars. And gas giants, they just cool down over billions of years until the internal heat runs out, the storms die, and the lights also go out. Jupiter, Saturn, they'll just be spinning in the dark long after everything interesting about them is gone. Brown dwarfs basically do the same thing because they weren't massive enough to ignite hydrogen. Yeah, you're right. These are the most boring deaths in the universe. But wow, am I learning so much about how things in space can die. However, at the heart of everything are stars. And you've been told it's just about white dwarf and supernova and black holes. But the life cycle of just how a star dies is actually insane, incredible, beautiful.

[00:05:35]I just must show you, Kyle, this image of Ton in his prime as a wallpaper on your phone, TV, or PC. Or even as a beautiful poster on your wall. The links are below.

[00:05:46]Here, put on these 3D glasses I got in this morning's Cocoa Puffs. This book has a map. You too, hamster. Chapter 3.

[00:05:54]This is the Hertzsprung-Russell diagram, and it literally shows how each and every star lives, evolves, and dies. All organized by temperature and luminosity.

[00:06:05]Basically, brightness. First up, the red dwarfs. The first object in the book to have hydrogen fusion, the definition of a star.

[00:06:13]Basically, when two atoms merge to make something bigger. These tiny things make up 75% of all stars in the entire universe. And here's the thing that blows me away every single time. Not a single one has died, ever. At least naturally by itself. The universe is 13.8 billion years old, and these little bastards live up for up to 12 trillion years. But why and how do they die?

[00:06:40]Well, unlike bigger stars, red dwarfs are fully convective, meaning the entire star churns like boiling a pot of pasta.

[00:06:48]All their hydrogen gets cycled through the core and burned.

[00:06:51]A star like our sun only fuses maybe 10% of its hydrogen, the hydrogen in the core, because the rest just sits in its outer layers doing nothing. Like me after I got fired from the law firm.

[00:07:02]Turns out I was way too biased in favor of gravity calls during trials. That's how I met my girlfriend during my divorce trial. Anyway, red dwarfs burn 99% of their hydrogen, and when they do eventually die, they won't become a red giant. No, they'll contract, heat up, turn bluish from being hotter, and then quietly collapse into a tiny helium white dwarf. But again, it has never happened. So, all we have is the theory.

[00:07:27]But now for the good stuff. And not my 25-year-old scotch, which you absolutely can't drink. But to find out how every star type dies, and how long it will be before they vanish from the universe entirely. First up, murdering our sun.

[00:07:43]Natural.

[00:07:44]Here in the middle of the HR diagram, we have many stars like our sun and also the orange dwarfs. Almost all of them will suffer the classic death that nobody actually properly understands.

[00:07:56]See, when a sun-sized star runs out of core hydrogen, the core contracts while the outer layers swell into a red giant hundreds of times bigger. But inside, the helium core is being crushed under what we call degenerate conditions where pressure and temperature aren't related anymore. Like if you apply pressure to achieve of gas, the temperature will go up. That doesn't happen anymore at this stage of the sun's life. So, when that core hits a hundred million degrees, helium fusion begins. But in a runaway explosion called the helium flash. For a few seconds, the core hits a luminosity of 100 billion times the sun's. That's brighter than an entire galaxy, but nobody outside the star can actually tell. The explosion is completely absorbed by the star's own guts. It's a hidden nuclear bomb, basically. Or the hidden truth of my depression that no one can see past my dim, dark, and joyless eyes. That's okay. Yesterday, I found out my ex-best friend got the free meal of the day at the local KFC. So, everything is fine.

[00:08:57]After this though, the star burns that helium for 100 million more years. Then it swells again on what's called the asymptotic giant branch, shedding its outer layers until all that's left is a naked core surrounded by a glowing glass shell called a planetary nebula. Those gorgeous Hubble images, corpse portraits. They last around 25,000 years before dissolving into space. Unlike other nebula which can live for millions of years, but also eventually, well, dissolve into space. And yes, it's called a white dwarf, but we'll have to come back to that in the next chapter because their death is somehow even more insane than in life. I mean, if we can count them as alive, I guess if I'm alive, they can be.

[00:09:42]But above those on the diagram, Kyle, are the big boys. Stars eight to 25 times the mass of our sun. These monsters burn through successive fusion shells like an onion. Hydrogen to helium, helium to carbon, carbon to neon, neon to oxygen, oxygen to silicon, and silicon into iron. Each layer burns faster than the last.

[00:10:00]Carbon burning takes a thousand years, and silicon burning only one day. Then then it stops, because iron is the end of fusion. Indeed, hamster, that's correct. Fusing iron doesn't release energy. It absorbs it. Yes, these massive stars become the super and hypergiants you know, all from aging blue stars, and yes, they go in the same direction on our diagram as the sun, like all stars do when they become red giants, but it's much faster and with a few more steps. See, the moment enough iron piles up in the core past an amount of 1.44 solar masses, pressure fails, and the entire core implodes at 23% the speed of light. The iron gets ripped apart by its own radiation, protons and electrons get crushed into neutrons, and the whole thing bounces. Yes, Kyle, a core collapse supernova. See, it's not an explosion. It's an implosion that bounces, like a bouncy castle when your fat ass jumps on it. Of course, what's left is either a neutron star or a black hole. But the largest stars above 130 solar masses, their gamma rays spontaneously create matter and antimatter, which drops the pressure holding them up. The core free falls, runaway fusion burns the entire star in seconds, and nothing is left behind. No neutron star, no black hole, the star is just erased from existence. This pair instability supernova is the only death in the universe that leaves zero remains. Literally vanished. And then there's the opposite extreme. Some stars above 20 solar masses don't actually explode at all. In 2009, a red supergiant 25 times the mass of the sun in a galaxy called NGC 6946 briefly flared out and then just vanished. No supernova, no shock wave.

[00:11:51]By 2015, it was gone from every optical telescope on Earth. The leading theory, the core was so massive it collapsed directly past its own event horizon without producing a shockwave. It just quietly swallowed itself into a black hole.

[00:12:06]Like the Bilbo Baggins of stars, right?

[00:12:09]Gosh. What? What do you mean what am I talking about? That, Kyle, is how every star in this diagram LIVES AND DIES. OH, what about the hot blue sub-warfs and Wolf-Rayets? Well, that's a great question, Kyle. How astute of you.

[00:12:23]Backseat reading ass Chapter 3, part 2, I guess.

[00:12:28]Well, hot blue sub-warfs are basically stars that got mugged during the red giant phase. Yes, mugged, not marked.

[00:12:36]Get your head out of the gutter. See, a binary companion gravitationally ripped their entire hydrogen envelope clean off. What's left is a naked helium-burning core about half the mass of the sun. They burn helium for about 100 million years, skip the giant phase entirely, and collapse straight into a small white dwarf. Just stripped, burned, and donezo. Just like that time I stole your clothes when you were at the gym and you had to run home naked.

[00:13:02]What? It was funny. Don't be so mad. Oh, speaking of being naked, let's talk about Wolf-Rayets. These are what happens when the most massive stars above 25 solar masses are so luminous that their own radiation and rotation blows their skin off at the rate of an entire Earth of mass every single month.

[00:13:22]Whatever remains on the star burns up to 200,000° and beyond.

[00:13:26]Yes, these are >> the hottest and brightest stars in the universe.

[00:13:33]>> Now, we've already covered how they die.

[00:13:35]Then you kind of supernova, except 10 times more powerful with relativistic jets exploding from the core, and we call them hypernova. So, what's next, Kyle? How can all these dead objects die more? Because they are still objects and they still can't exist forever. The universe has to make them vanish at some point, right? Or does it?

[00:13:58]>> Chapter four.

[00:14:01]>> Yes, corpses that are alive. A white dwarf starts at over 100,000 degrees, but it can't fuse anymore. It's a ball of carbon and oxygen the size of the Earth with the mass of the Sun, and all it can do is cool down. And obviously, as it cools, the core slowly freezes.

[00:14:18]After about a hundred trillion years, it goes completely dark, a black dwarf. But even that is not the end, Kyle. It still has more to give. See, if protons, the building blocks of all atoms, exist forever, the atoms inside the star will still slowly fuse through quantum tunneling at zero degrees, converting everything to iron over a time scale of 10 to the power of 1,100 years. If you wrote that number out, it would take an entire book. And once enough iron builds up, the star's own weight exceeds what it can support, and it collapses. A dead, frozen, invisible star that hasn't done anything for longer than any number you've ever conceived of explodes. An iron star black dwarf supernova, the last supernova in the universe.

[00:15:10]Insane, right? But what about neutron stars, I hear you ask. They are trillions of degrees hot and will cool to almost zero over a hundred trillion years as well, losing their magnetic fields. The magnetars and pulsars also their rotation. They have already collapsed way past the point where they could become a black dwarf though.

[00:15:28]That's a white dwarf exclusive. In fact, neutron stars will only die when all matter dies in chapter five. So, let's go there now.

[00:15:36]Yes, Kyle, black holes will die from Hawking radiation, which is when the empty space around a black hole randomly creates tiny particles and the black hole accidentally gives its own energy to them. It's literally being pickpocketed by the universe until there's nothing left, just like anyone vacationing in Rome. I know you know that, Kyle. Why are you stopping so?

[00:15:56]Hey, stop that. They will all evaporate, yes. A stellar mass one takes 10 to the 67 years. A supermassive one like TON 618, 10 to the 100 years. That's a Google. But, they do die. Even black holes aren't forever. So, when some dip says that as the marriage vows like Mongolian horse did with his first wife, make sure you stand up and boo.

[00:16:17]And in case you were wondering, galaxies die because the gas runs out, the black holes eat what's left, so nothing new can form. The stars then die one by one and eventually it's just corpses and darkness. So, what's left in the universe to die? Yes, Kyle, it's finally time. Chapter five, when does all matter itself vanish?

[00:16:37]See, grand unified theories in physics predict that protons aren't actually stable. They should eventually decay into lighter particles. And we've been looking. The Super-Kamiokande detector in Japan has been watching 50,000 tons of ultra-pure water for decades, waiting for a single proton to fall apart.

[00:16:57]Current answer? If it happens at all, it takes longer than 10 to the 34 years.

[00:17:01]But, if protons do decay, then every atom, every rock, every frozen neutron star eventually just dissolves. And that means no black dwarfs either. All the stuff in the universe that isn't dark matter or dark energy will just cease to exist. Nothing left but stray particles and radiation that can never form anything again. But what even at the smallest scales, like say the Planck scale, 10 to the minus 35 meters, where space-time itself boils into maybe quantum foam, and what we call matter is really just vibrating strings of energy in 11 dimensions. A dying universe would maybe have these simplest lowest energy hums of strings left, drifting forever until the universe really dies. And there are many ways that can happen.

[00:17:45]Wait. Why do you look so mad? Wait.

[00:17:47]Where did you get that weapon? No, no, no. No, no. Don't use it. I don't want to see how the universe ends. No!