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How Old Are The Atoms In Our Body?

  1. Nov 1, 2010 #1
    How "Old" Are The Atoms In Our Body?

    Richard Feynman once said,

    "So what is this mind of ours: what are these atoms with consciousness? Last week’s potatoes! They now can remember what was going on in my mind a year ago — a mind which has long ago been replaced. To note that the thing I call my individuality is only a pattern or dance, that is what it means when one discovers how long it takes for the atoms of my brain to be replaced by other atoms."

    He's apparently referring to a research which concluded from radio isotope tracings of chemicals entering and leaving the body that we replace around 98% of our bodies’ atoms every year or so.

    Can anyone show me to an article or discussion on this topic? I find immensely interesting the fact that the matter which forms us is constantly being renewed and would like to look into this with more detail.
  2. jcsd
  3. Nov 1, 2010 #2
    Re: How "Old" Are The Atoms In Our Body?

    Depends what you mean by how old!
    The protons and neutrons in the atoms in your body date to the big bang.
    Most of the atoms date to the start of the galaxy when they were formed in either metal poor early stars (for the light elements) or supernova (for the heavier ones) - say 10 billion years old.

    If you mean how long have they been part of you as opposed to the surroundings - then it depends on the tissue. Some parts get replaced in days some last for a few years, depends how much wear they are subject to. Things like blood and skin get cycled quicker, bones slower.
  4. Nov 1, 2010 #3
    Re: How "Old" Are The Atoms In Our Body?

    Thanks for the reply. Yes, I know they date from the Big Bang, what I mean is how long they have been in our bodies.

    Apparently, the original research on this topic was published on the 1953 Smithsonian Institute Annual Report. So, if anyone has access to this (I don't):


    Also, I found this article on the topic:


    If someone can provide us with concrete data, that would be great!
    Last edited by a moderator: May 5, 2017
  5. Nov 1, 2010 #4
    Re: How "Old" Are The Atoms In Our Body?

    Don't have a link to that paper,
    Some whiteblood cells last less than a day - they are made to fight a particular infection then die. Red blood cells last 3-4months. Stem cells last your whole life.
    Even your bones are regrown, about 10% of the calcium is replaced every year
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