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Homework Help: The origin of Caesium-133

  1. Mar 16, 2012 #1
    Dear Physicsforum,
    I have a rather simple question, which can probably also be solved with a rather simple answer. I am writing a paper on the history of the perception of time, on the scale of the big bang up until now. In this I use that nowadays the definition of 1 second is based on Caesium-133 atoms. I was wondering if you could tell me when (approximately) the first Caesium-133 were formed in our universe, as this is, in a very abstract way, the origin of the modern second. Information about the process itself would be welcome. As far as I can tell, it is probably like all the other heavy elements, as in that it was formed in supernovae, however I remain uncertain.
    What I found on my own was that several of the Caesium isotopes are synthesized from lighter elements by the slow neutron capture process (S-process) inside old stars, as well as inside supernova explosions (R-process), however it doesn't specify if the 133 variant is among them.
    Would it be wrong to assume that the first supernovae occurred around the time the first stars formed, ~400 million years after the big bang? And would, if I can assume that, it be fair to say that the first Caesium-133 might also have been formed at that point?

    I understand that this doesn't fit the standard format of the homework questions, and I apologize if this is not what this forum is designated for.

    Thanks in advance
     
    Last edited: Mar 16, 2012
  2. jcsd
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