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Originally Posted by stitt29
A question about supernova. I assumed when a star became a supernova it exploded and it threw out all its matter for miles. Then I read the star doesn't explode it collapses into a denser body all that is ejected is a shockwave and heat and light. Which is correct?
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Both. There are several types of supernova.
The first is probably an oversimplified view of the death of a large star, which throws off its outer layers as it collapses - a core "star" always remains however. Other types of supernova repeat by accumulating mass from a companion star and then throwing off a surface layer each nova as fusion temporarily restarts.
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Also because I am assuming that stars collapse into a denser body, how does the theory that there were no heavy elements until the first generation of stars exploded sending heavy elements across the universe work?
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Stars make heavier elements as they burn by fusion. So when they die they have accumulated a lot of heavier elements.
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To escape a planets gravitational pull requires the projectile to be moving at X m/s if the star collapses into a denser body the gravitational pull will increase requiring an even faster speed for any projectile.
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Gravitational pull is only proportional to mass and distance. So gravitational pull at the same distance is exactly the same. It is only surface gravity that is affected.
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If the star collapses and becomes a dark hole not even light can escape this gravitational pull. Just wondering how heavy elements are supposed to have spread throughout the universe taking all this into account
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When large stars supernova a lot of matter is thrown off.
Only very large stars can collapse into black holes when they supernova, and even they often avoid the fate by throwing off so much matter in the supernova that they are no longer masive enough to gravitationally collapse.
But yes, there is an awful lot of matter locked up in black holes.