After supernova?!

  1. It is going to be a long question, thanks for reading and answering it on advance,

    In order to get a star explode as a supernova, it should be big enough and should finish its fuel (hydrogen) after the star explodes as a supernova the iron in center fused to heavier elements such as gold, chrome, lead etc and diffuses all these things and rest of the star to space and forms a nebula. Then gravity takes its role and starts getting hydrogen atoms together again and forms new stars.
    My question is, that star exploded as supernova finished all hydrogen it had before the explosion and as a result of explosion heavier elements occured, how come hydrogen atoms get together to form new star, as there is heavier elements which are bigger in mass aswell shouldnt those heavier elements have bigger gravity to get everything together in the center of the nebula? and where do hydrogen atoms come from as star finished all hydrogen before it exploded?
    Mustafa AYDIN
  2. jcsd
  3. mathman

    mathman 6,430
    Science Advisor
    Gold Member

    There is plenty of hydrogen around outside of individual stars. It makes up about 75% of the baryonic (ordinary) matter of the universe.
  4. Chalnoth

    Chalnoth 5,134
    Science Advisor

    1. Most of the normal matter in the universe has yet to ever collapse so far that it forms a star.
    2. Large stars don't process all of their material. They go supernova when the iron core reaches sufficient size that it can't support its own weight. That happens long before the entire star is converted into iron.
  5. Drakkith

    Staff: Mentor

    Also, when a supernova happens, the core usually collapses into a neutron star or black hole. The formation of gold, lead, and heavier elements happens from the force of the explosion itself on the outer layers of the star. This fuses certain amounts together into heavier and heavier elements.
  6. Good question. In your typical supernova most of the matter ends up unburned. The star will go boom when the core has 1.4 solar mass of iron, but if you have a 20 solar mass star, the outer layers will still be unburned hydrogen.
  7. When the shock goes through the iron and silicon layers, you do get some production of heavy elements, but there is very little fusion when the shock goes their the hydrogen layer. The problem is that hydrogen takes a while to fuse, and so when you throw a shock wave through hydrogen, it happens too quick for anything much to happen.
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