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Oldest part of the galaxy that could have held life?

  1. Sep 26, 2014 #1
    What is the oldest part of our galaxy that theoretically could have held life some millions - billions of years before earth? I'm asking purely out science fictionic curiosity.

    This may sound like an even dumber question, but is there any region on the "map" of the galaxy that contains these most ancient groups of stars? Now I have heard of globular clusters, but I don't know if those are actually the current theorized "oldest" stars since the Milky Way was formed.
  2. jcsd
  3. Sep 26, 2014 #2
    Look at the link, see if it helps... http://www.ifa.hawaii.edu/~barnes/ast626_95/pcmw.html [Broken]

    You'll need to know about "metallicity" and pop I and pop II stars, and need a picture or map of the galaxy.

    The early stars formed from just H and He. The term "metallicity" refers to all other elements as metals, and indicates the degree to which a star or star population has them. Later stars have higher metallicity dues to being formed from some of the "metals" having been created and dispursed by super novae.

    The earlier stars are called population II and the later ones with greater metalicity as population I. (The numbering seems backwards because the later ones where identified first, I think).

    Metallicity is needed to form planets, so what you are asking is, where in the galaxy are the oldest pop I stars, or where are the oldest stars with greater metallicity.

    It is a little confusing because the original simplifying assumptions about all this have been overturned a few times... the structure of the galaxy through time is complicated; but the site linked walks through it pretty well... maybe enough that if you have a map of the galaxy (or draw your own) you can follow along and see if your question can be answered doing that.
    Last edited by a moderator: May 7, 2017
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