1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted