Lifecycle of massive stars | Stars, black holes and galaxies | Cosmology & Astronomy | Khan Academy
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Lifecycle of Massive Stars. Created by Sal Khan. Watch the next lesson: https://www.khanacademy.org/science/cosmology-and-astronomy/stellar-life-topic/stellar-life-death-tutorial/v/supernova-supernovae?utm_source=YT&utm_medium=Desc&utm_campaign=cosmologystronomy Missed the previous lesson? https://www.khanacademy.org/science/cosmology-and-astronomy/stellar-life-topic/stellar-life-death-tutorial/v/star-field-and-nebula-images?utm_source=YT&utm_medium=Desc&utm_campaign=cosmologystronomy Cosmology & Astronomy on Khan Academy: The Earth is huge, but it is tiny compared to the Sun (which is super huge). But the Sun is tiny compared to the solar system which is tiny compared to the distance to the next star. Oh, did we mention that there are over 100 billion stars in our galaxy (which is about 100,000 light years in diameter) which is one of hundreds of billions of galaxies in just the observable universe (which might be infinite for all we know). Don't feel small. We find it liberating. Your everyday human stresses are nothing compared to this enormity that we are a part of. Enjoy the fact that we get to be part of this vastness! About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content. For free. For everyone. Forever. #YouCanLearnAnything Subscribe to Khan Academy’s Cosmology & Astronomy channel: https://www.youtube.com/channel/UChNPnEkW8LYZ5Rwi8_A2-DA?sub_confirmation=1 Subscribe to Khan Academy: https://www.youtube.com/subscription_center?add_user=khanacademy
Comments
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It was once said, although I cannot quite remember who said it, miht even have been an astrophysics lecturer "High mass stars are like rock stars, they live fast, die young and leave interesting bodies!!"
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Iron kills the star because it drains the star and when the Iron reaches about 1.4 solar masses and then the star collapse. I heard once it goes supernova the Iron core will form new elements.
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I have a question, if Neon has a higher atomic number than Oxygen, why is it in the shell further out?
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So weird I've always had endothermic in my mind as a chemistry word, but of course it works in nuclear fusion as well.
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Half as long, twice as bright.
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@INMATE2468 yeah because they use up(burn) their energy(helium) faster!!. than less massive stars.
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@TheMrNomus Epic comment is epic
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Who the fuck disliked this? I'd find him and force to study the whole astrophysics course.
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@TomFynn wikipedia ftw
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So the bigger they are the faster they die????
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@tIs4gatorbait and then when there is enough dense helium in the core, it passes a threshold where the the mass of He is enough for the gravity of the stars mass (which doesnt increase; is actually decreasing) reaches that temperature where He can fuse. And the star needs to have enough mass to begin with to make He reach that temperature, otherwise it doesn't burn. And I assume it becomes a white dwarf, or maybe just switches into a brown one?
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im a little confused about the core collapsing (3:20 or so). i may have this right but im not sure: hydrogen fuses into helium. the He is less massive than the hydrogen made to fuse it (since 6 H atoms are needed), but the He is denser. So, the core is smaller even though it is less massive when it had only H, and then the gravity of the rest of the stars material is acting on a smaller surface area which causes the H to heat up and fuse faster, whose extra energy pushes the stars materialout
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@ShaheemA13 Not as fusion generated photons as in stars, but thermal emulsion from the surface, synchrotron radiation from their rotating magnetic fields and X-Ray emission from matter falling in from a possible accretion disc formed from remnants of its original sun.
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do neutron stars radiate light?
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Thanks
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@dalcde Because Neon disintegrates at super-high temperatures whereas oxygen does not, so even though the neon is heavier it doesn't sink as far. Wiki 'neon burning process'.
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@superdau clarification: the layers have to do something with density, but not with the densities we are used to.
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@dalcde Oxygen burning happens after Neon burning, because it requires higher pressure and temperature. So it has to be inside the Neon shell. The layers don't have to do anything with density or weigth.
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Why is the neon outer than the oxygen?
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looking forward to the next video
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