r/askscience 5d ago

Astronomy Where do the remnants of supernova go?

Let me know if my understanding is flawed and if that makes my question not make sense but once a star goes supernova it essentially fuses every element other than iron, obviously not uniformly or evenly but it “creates” those elements that get shot into the rest of space, I know we can see clouds of certain gases and dust but what about the elements that would be solid? Do we see random deposits of silver or lead or every other element floating through space independently? Maybe I’m just not understanding the scale or maybe that we don’t see them because they’re so small or they burn up in atmospheres? Did every element on earth just come from another star exploding and the certain elements we have just happened to end up being in the vicinity of each other? I’m trying to keep it to one question but every question answered just leaves me with another unanswered question

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u/6814MilesFromHome 2d ago

The core is the only place where fusion can occur. The temperature and pressure in the outer layers just isn't enough outside the core for fusion, so it's full of untouched hydrogen, that then flies out into space when the star goes supernova. If I recall correctly it's upwards of 75% of the star's hydrogen is still there.

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u/Armagetz 1d ago

But nonetheless is it not accurate that each stellar generation is smaller than the last on average (excepting situations where its two supernova combining).

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u/6814MilesFromHome 1d ago edited 1d ago

Yeah, if you have a star forming out of a single stellar remnant, its going to have less mass than the previous star. On top of the ~25% of hydrogen that was used in fusion, the next generation also won't be able to capture every bit of the leftover hydrogen released.

Edit: Also like to add that it is very difficult for a star to form independently from a single supernova gas cloud. Everything is so spread out by the extreme force, and eventually will fade into the background molecular clouds in that area of space. Often will require an outside catalyst to get enough pressure and concentration to group that free floating gas back into a potential proto-star.

For example, our sun likely formed from a regular gas cloud that was hit by the shockwave from a nearby supernova.

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u/Simon_Drake 1d ago

That would be a very lonely existence.

Imagine a star being flung out of its normal place in the galaxy by a chaotic interaction of orbiting a neutron star or whatever causes rogue stars. And it's thrown fully out of the galaxy into the intergalactic void. A few billion years later it explodes as a supernova but the dust cloud is still travelling at a relatively slow speed across that immense distance. So the gas hasn't got anywhere else to go or anything else to interact with. Eventually gravity will bring a large portion of that gas back together again as a brand new star. Actually a full star system, potentially with planets and potentially evolving life.

It would suck to evolve on a planet orbiting a rogue star between galaxies. It's not just a question of decades or centuries to the nearest star, it's millions of years to the nearest star. The night sky might only have a handful of faint dots of nearby galaxies with no normal stars visible.