Correct-Answer to Question #4:
Where are heavy elements created?




Q.  Where are heavy elements created?

A.  It depends on what you mean by "heavy elements".

Q.  Elements heavier than Iron or Nickel, with more than 62 nucleons in the atomic nucleus?
A.  Elements heavier than Ni-62 are produced at the Core boundary of planets.

Q.  Is this the standard explanation?
A.  No, the usual story is that heavier elements are produced in supernova explosions.

Q.  What's wrong with this explanation?
A.  Supernova explosions only last a few weeks, they couldn't build up a heavy nucleus like Uranium through prolonged impact of neutrons.

Q.  What else?
A.  Looking at elements on Earth or in meteorites, none are older than 4.7 billion years. This couldn't happen if Earth matter accumulated from random supernova products.

Q.  Where can I find out more about heavy-element production in planets?
A.  See "XT804: Heavy Elements are made in Planets, not Stars", at http://www.aoi.com.au/Extracts/XT804.htm .





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