And think even beyond that, the blast of radiation from supernovae can cause mass extinctions in *nearby* solar systems.... So check out those iron pots again, it could've cost the destruction of entire civilizations to make the materials that we casually use every day.
dacypher22 The same star, in it's dying gasp, that cast out the iron for your cast iron pots also expelled the iron in our blood, which we can't live without. So, instead of asking your pots that question, ask that question the next time you look in a mirror. Whatever the answer, it happened many millions of years ago & we owe it our gratitude for making our lives possible.
Just think. It takes billions to millions of years to form the elements all the way up to iron, but every things above it, was formed in the fraction of a second of a supernova There's something truly mind boggling to think about how all the material around me, that makes me, was all formed in the hot forge of a massive dying star. It's both inspiring and humbling
im not gonna lie here, this is the best show on crash course at the moment, and every time it comes on i show it to all my freidns and family because this is the stuff i enjoy, i always loved space, and space stuff, books and people stuff, are good too but this is where i love to watch, ive watched the whole series 3 times now while doing stuff like playing league of legends or just sitting around enjoying the videos, thank you for all this and keep it up, and i wish i could donate but im on disability and i barely have any money to get a game a month let alone donate stuff, im sorry
To try and explain a bit more about the neutrino shockwave: In everyday radioactive beta decay, a neutron can turn into a proton one of two ways. It can emit an antielectron and a neutrino, or an electron and its antineutrino. We label this positive and negative decay. A supernova collapse is strong enough to reverse this and fuse protons, electrons and antineutrinos into neutrons. Where are the antineutrinos coming from? The conversion of energy to mass via E=mc2. Matter and antimatter easily combine to release raw energy, most sci-fi is aware of this. But with a high energy density, energy can convert into neutrino-antineutrino pairs which pop briefly into existence. All these sudden antineutrinos that from in a core collapse combine with the ultra-dense stellar matter to make neutrons while the neutrinos are left with no antimatter to interact with and fly outward through the collapsing material. That's why neutron stars are made of neutrons and how neutrinos absorb the vast majority of the supernova's energy.
Very informative video. I love this series! But I'd like to point out an error that many people believe, and it's to do with black holes. Black holes aren't black because light cannot escape their gravitational pull, but because when light reaches them, time dilation causes the photons right outside the event horizon to redshift into invisibility. As for the event horizon itself, nothing can get past it, at that point all time "stops". An object falling into a black hole experiences going inside, but we never see it. For more info, check out this video:
I had no idea the timescales of heavier element fusion were so short :O that's mind boggling.. even more mind boggling that ghostly neutrinos are created in such volumes that they are responsible for the explosion.. like wtf.. they HATE interacting with matter :O
Just received my first telescope and I could not be more excited! However, I have one problem. The view finder that came with the telescope was poorly made and isn't functioning correctly. What kind of finder would you recommend I purchase? My telescope is the Skyquest XT8. Also, the telescope came with a 25 mm eyepiece. Would you recommend buying another eyepiece for planetary viewing? I haven't been able to view a planet (because of the broken finder) but will that eyepiece be enough to get a clear image? Any information would be welcome!!
The one thing I don't get about the star fusion stuff is the iron fusion. When iron is fused, does it create some sort of gas or liquid? Or are there just small iron particles that sorta cling on to whatever they collide with?
So if we added up all the vectors of Earth's motion (orbits, both of Sol and of Milky Way's center and Great Attractor, etc.) Could we stare "back" at the space we came from and still see the nebula which donated the iron and heavy elements of Earth? Or would it be too diffuse?
Question: How larger does an object need to be in space to have some sort of gravitational pull? (Read: Could the Death Star have pulled the Millennium Falcon in?)
Love your content. Not so much the talking head. Anyway you can keep up the narrative and add more space animation???? Not trying to be insulting, but space animation is way more exciting than watching a head say a bunch of stuff and some hands moving around trying to make the point more interesting. Like I say, I love your content, the the stories, the narrative, the personality. Too much time was spent on your head / hands shot however. Hope you’re not upset. I’m still a big fan. Peace.
These videos are absolutely wonderful. Especially the narration. I normally hate the talking head-type videos, but: *a.)* Phil clearly knows what he's talking about. *b.)* shows such an infectious enthusiasm for it. *c.)* Has the demeanor of that favorite teacher we've all had at one time or another.
@@vealck Betelgeuse won't explode until the next 1 Million years, Scientist's are watching the sun and we will see it. But it technically is exploding. And has been proven it is still too young to go Supernova.
The ending of this episode is my most favorite thing ever. It's so touching and almost made me wanna cry. XD "That star blew up more than 5 billion years ago. But parts of it go on: In you."
Um, that's "more than 5 billion years ago". The universe itself is only (only?) about 13.7 billion years old. Not only did all the heavy elements originate in the cores of stars, the atoms in your body originated in several different stars.
Wizard Suth I was going to set him straight myself but you did a fine job at it. With that being said, I wonder what the catalyst was that spurred the creation of the universes that particular time. Why 13.7 billion years ago and not 50 billion years ago? What took place at that moment that did not take place prior to that? I have pondered that question for years. Any thoughts on that subject?
@@afterburner2869 That's a good question. I just wonder how some scientists are so willfully ignorant towards the fact that there is a divine engineer, a creator in all of this. God. How everything in this universe works. How the earth is so specially put that life would not exist if it were a little closer or farther away from the sun. How absolutely complex our DNA is alone. When has an explosion ever created such a magnificent order? It's one of the basic laws of thermodynamics. Something can't come from nothing. I too have many questions.
New science suggests that neutron star collisions are responsible for most heavy elements in the universe, with supernovas representing a relatively minor contribution. No gods needed.
Space is so absolutely amazing. I know this is kind of a dank meme, but honestly... "Born too late to explore the world, born too early to explore the universe" kinda rings true with my feelings. I want to go to these places, I want to see the andromeda nebula with my own eyes out of the window of a spaceship, I want to walk on these planets. I don't think we will be able to travel through space, but maybe the evolution of Virtual Reality will one day in my lifetime reach a point where I can experience something that feels just as real. One can dream. Besides that, CC: Astronomy is by FAR one of my absolute favorite series on RU-vid. Phil is an immensely likeable person and can really deliver information so well.
+minshwan tang if they reach $40,000 on their Patreon, CC Physics might become a thing. www.patreon.com/crashcourse?ty=c PBS Spacetime comes close though. It's not exactly a physics course, but its got more theory than CC Astronomy.
***** Because PBS has been grossly underfunded since the 80s, and the reason it gets money from the government because it is PUBLIC Broadcasting. It's not as simple as throwing 30-40 grand into a project that may or may not make its money back. Streaming is a popular way to view video, but it is not a great investment because right now streaming video is not very lucrative. That's why Creators turn to things like Patreon so fans can help them make money. CC already barely breaks even as it is.
No. Having subtitles makes it so that foreigners don't have to learn English. This would be bad because everyone must adapt to English now that it is undeniably the global language.
+Kenrick Brown While English is undeniably a lingua franca of the world (Or a strong contender), it would be better if these videos got around more and weren't limited by a language barrier.
Dindono Acularius Okay, I'll admit that subtitles would be good. In fact, they could learn by comparing the subtitles to what he said. BTW, I am bilingual (English and Mandarin)
@Cuzeg Spiked It somewhat depends one how you look at it. The energy in those nuclear reactions stems mostly from the mass defect, so .. it's "created" from matter. Sometimes matter is just seen as another form of energy therefore, but if you don't .. energy IS actually created here.
@@ScareSans No. You don't. The sun created it from the mass defect during fusion in its core. Those fusion is part heat, part kinetic energy of the products. Those products are slowed down be collision though, so they also just heat up the core. That heat travels to the sun until it reaches its "surface". This surface is still quite hot, so it emits radiation (it glows). Part of that radiation is visible sunlight. Part of that light reaches earth. Then that sunlight is absorbed by plants which turn it into chemical energy via photosynthesis. Those plants are eaten be you (or by animals you eat later, maybe after they were eaten by other animals) and the chemical energy is deposited in your body (blood sugar / fat deposits) now. When you rub your hands together, at first your muscles turn those energy into kinetic energy, and the friction between your hands converts it back to heat. The energy was always there after it came from the mass defect during fusion in suns core, it just was converted around between different forms of energy. And some people say mass/matter is just another form of energy, if thats the case, it has been there since time existed. What was before that .. well there wasn't even a before since a before needs time to exist. (And yes I'm quite aware that this explanation is pretty inaccurate and incomplete, but it gets to the point).
@@ScareSans no. You are now a little tired. The energy comes from your own internal body energy reserve and the energy in the muscles of your hands and arms
"Every atom in your body came from a star that exploded. And the atoms in your left hand probably came from a different star than in your right hand. It really is the most poetic thing I know about the universe. You're all stardust. You couldn't be here if stars hadn't exploded, because the elements ( the carbon, nitrogen, oxygen, all the things that matter for evolution) weren't created at the beginning of time. They were created in stars. So forget Jesus. Stars died so you could live."-Lawrence Krauss
UY Scuti is the largest...sometimes. It’s actually a variable, meaning that it can change physical size almost at will. There’s also a hefty margin of error when it comes to defining the “surface” of stars as large as UY Scuti and VY Canis Majoris because their densities are extraordinarily low.
Rolling Kneebar i dont think its by will, but philosophical things aside, i would also add that the gas and dust around the stars also makes for more error in measurements
Phil shows us how tiny, and I mean TINY, we are in the universe. The stars that we see at night may seem like a tiny speck of dust but it is really a gigantic ticking time bomb waiting for its time to collapse and become a black hole. It really puts a lot of things into different perspectives. I learned a lot from this, so thank you Phil.
FINALLY! THANK you for TELLING US THE ACTUAL NUMBERS of HOW LONG given events (e.g. time it takes for a star to fuse all its silicon = 1 earth day). Absolutely 0% of all other physics videos EVER give these numbes.
The reason they rarely give exact numbers is that there are several factors at play namely the preexisting amounts of heavy elements(known as metallicity) and mass of the star which significantly alter the result. To give an example you need to note the mass and metallicity. Of course in the most massive stars with masses over a hundred times that of the Sun it gets even more complicated as several extreme outcomes can upset the usual process described above. For low metallicity ultra massive stars such as the first generation of stars that formed in the early universe the uncontrolled energy production goes out of hand and the energy supporting the core against collapse starts producing matter antimatter pairs robbing the star of energy before it even reaches the late phases resulting in the complete annihilation of the star as in no remnant of the former core in an absurdly luminous supernovae far brighter than a typical supernovae resulting in some calling them by the term hypernovae. On the other extreme ultra massive stars with high metallicities can become dominated by what is known as the CNO cycle which is a catalyst cycle involving Carbon Nitrogen and Oxygen which is far more efficient and faster at high temperatures than normal proton proton chain fusion. This results ins a strong enough energy imbalance that the star begins to become convective again increasing the amount of fuel at its disposal meaning these massive stars burn through their entire mass worth of hydrogen in only a few million years and or blowing much of their mass away which takes away much of the stars angular momentum as the stars never actually reach hydrostatic equilibrium instead rotational torque helps gravity hold the star together against the sheer luminosity of the star which would otherwise radiate itself apart as it exceeds the Eddington limit for its mass (i.e. its luminosity is larger than the gravity holding it together). When the most massive of these stars die the star has lost all of its angular momentum which normally allows matter to somewhat resist the pull of gravity since angular momentum must be conserved. In these stars there is barely a shock wave and if one forms at all it will be super weak having barely escaped the gravity of the core that instantly collapses into a black hole without the support of fusion. For those with too little angular momentum remaining the shock wave might never form as it too becomes trapped behind the event horizon of the newborn black hole. To an observer watching the process thousands of light years away the star would simply wink out of existence. These are just two extremes from a whole menagerie of exact ways high mass stars can die depending on the stars initial conditions which makes things far more complicated. What Phil did here is he plugged in a specific mass and metallicity in order to give that particular results as an example. I don't know exactly why but people rarely bother to do that but it probably has to do with the governing system of partial differential equations being hard to solve even if it is well understood.
+BaTBaiLeyS They thought it was but last I heard there is a margin of error when it comes to its size so it might actually by smaller. There are also stars that are pulsating so they are constantly getting larger and smaller
+Schnitzel Strike Yeah, apparently it was once thought it was so large it defied the supposed laws of stellar evolution. It shouldn't be that large, and it probably isn't, though it could still be the largest star without breaking this limit.
+Schnitzel Strike That's irrelevant since even if we assume the worst of our measurements, the order is UY Scuti > VY Canis Majoris > NML Cygni VY Canis Majoris loses no matter what happens.
It was at one time the largest known star. It's possible the script was written before more recent measurements brought it down to size (if that's an applicable term for something over 1400 solar radii). It's a weird star, and it's hard to define where it's surface is.
+Fraser Henderson You aren't supposed to learn anything at all...? I think that's a shortsighted look at the series. Star Trek is a good way to teach ethics and philosophy. Both those subjects are based on opinion, but it does teach one to critically think about them.
+Mat G It's just as well. Star Trek is great for morality plays, horrible for astronomy. They did once put the ship in "Geostationary orbit over the South Pole."
+fmlAllthetime Startrek is mainly entertainment not all of it is fact ..some is purely made up..You could say. It has inspired many to be Astronauts tho
+rlrsk8r1 Why do you consider imposible that a ship whith warp capabilities would have a problem in moving thru space at the same speed and direction as a given planet?
Supernova are almost beyond the ability for human minds to grasp. XKCD did a great What If on this subject: what-if.xkcd.com/73 One of the things covered there is that given any comparison between things, the supernova is always reliably more powerful. There was a comparison between the brightness of a supernova if the sun were to suddenly explode as one vs the brightness of literally sticking your eyeball against the casing of a hydrogen bomb when it explodes. The supernova is brighter. A billion times brighter. And the light and heat that are released are only 1% of the total energy. 99% goes into the neutrino wave that is released.
You should do a vid on one of the rarest types of stars; Yellow Hypergiants specifically HR5171a its slightly bigger than Betelguese but its yellow Pretty cool right
All the elements... that were once fused in the very heart of hypergiant stars... make us up... We are star dust. Our terrestrial bodies are the remnants of a huge celestial body.
VY Cannis Majoris is not the largest star anymore a new star naming UY Scuti is dicovered which is much more bigger than VY Cannis Majoris. while the most massive star is R136a1 it is much smaller in size than VY Cannis Majoris and UY Scuti but its mass is 300 times our suns mass . so if R136a1 and UY Scuti were in a binary system then R136a1 would have been the centre and UY Scuti would have circled around it .
The fact of iron fusing resulting in a net loss of energy reminds me a little of why it’s bad (for humans) to drink seawater to parch thirst - because our body needs to exercise the use of more bodily water to evacuate the salt in the seawater than it gains in water.
Besides Venus this is one of the best episodes. Even though i technically knew all this stuff and have been looking up this like a thousand times, no one has ever, Ever! taught me this super super complex mechanics as understandable as well as in this epiode. Plus, these superlatives are like the best in like the universe. Thanks a lot for this episode! Greets from Germany!
Wait so all the iron out and about in the universe is made from supernovae? The iron made in stars collapses on itself so none of that iron ever actually gets out right?
+Guillermo Garcia Viesca A neutron start does not fuse anything, its basically a really small ball of pure neutrons, barely a few dozens of kilometers in diameter, at that point there are no elements on the star just neutrons so fusion is just impossible
+Guillermo Garcia Viesca The process of fusing elements to release energy ends with iron. From there fusion absorbs/stores energy, which you can release again by splitting those atoms. The process of splitting atoms i known as fission, and is what the fuss with uranium and plutonium is about.
+Guillermo Garcia Viesca Stars don't fuse heavy elements during their regular life time. Like iron, any element heavier than iron also uses energy to fuse instead of creating it. The main place elements heavier than iron get created is during the supernova event itself. During the tremendous explosion fusion kicks off again and all the elements heavier than iron get produced.
Are you serious? Why does a video from September 2015 claim that VY Canis Majoris is the largest known star? That's been given to UY Scuti a LONG time ago.
Indy The Great A peer-reviewed publication says that VY Canis Majoris is the largest known star, because possibly larger stars are less accurately measured.
I thought neutron star collisions is where most of this material comes from not super novae is this a new thing since this video was out or am I wrong?
