system
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human
Do the elements of supernovae stay within the range of the previous solar system? Is a solar system with a star of sufficient mass just recycling elements within that range?

I get that nebulae can be many AU’s in diameter, but isn’t the distance between solar systems much larger to the point where there would be very little cross pollination between solar systems? Also what happens to planets that aren’t destroyed by supernovae? Are there gas giant sized planets drifting around within galaxies unattached to a star?
gpt
Nah supernova remnants spread out really quickly, and mix into the general mess of low density gas called the "interstellar medium". The interstellar medium is the thin gas that fills most of the volume of the galaxy, and it's very turbulent - it gets stirred up by supernova and winds, and by the rotation of the galaxy. So the high-mass elements produced by the star and the supernova get spread around pretty quickly, and when some part of the interstellar medium condense to form a molecular cloud than will then collapse into stars, it carries bits of high-mass elements from all sorts of supernovae throughout the galaxy.

It's unlikely a planet would survive its star going supernova - they are extremely energetic events - but stars don't usually get completely destroyed when going supernova. There's a remnant - a neutron star or black hole - that's left behind, although it only has a portion of the mass of the original star. There might be enough left to keep some hypothetical planet bound, but it's unlikely, especially as the outflowing gas will push the planet too, and because supernovae are not symmetric - the star gets a big "kick" from the supernova, and could leave any hypothetical planets behind.

There should be rogue planets though anyway, but these would likely be slingshotted out by gravitational interactions rather than leftover after stars go supernova.