• Question: Is the earths total mass heavier, lighter or the same as it was say... 10,000 years ago?

    Asked by oijonnx to Ben, Jony, Katharine, Mark, Peter on 18 Nov 2011.
    • Photo: Jony Hudson

      Jony Hudson answered on 18 Nov 2011:

      Hmmm, good question. And I’ve no idea what the answer is. I guess stuff like meteors and dust from space fall on the earth all the time. And I suppose some of the atmosphere leaks away in to space. But I don’t know which happens quicker, so I’ve no idea. Sorry about that!

    • Photo: Katharine Schofield

      Katharine Schofield answered on 18 Nov 2011:

      No idea either! and I doubt we could measure any change with sufficient precision – if it is changing, it wouldn’t be by much so you’d need some very sensitive measurements.

    • Photo: Peter Williams

      Peter Williams answered on 18 Nov 2011:

      I don’t know.

      I do know that the earth’s rotation is slowing as the tides transfer angular momentum to the moon’s orbit. You would think that as that happens we would lose less atmosphere into space as the centrifugal force lessens. But there could be some other effects i’ve not thought of.

    • Photo: Mark Basham

      Mark Basham answered on 18 Nov 2011:

      Think you have asked a question that has stumped us all 🙂 I don’t really have a clue, No big impacts have happened in that time, and apart from the possible slight gains and losses, I suspect the answer is about the same. but really cant be sure.

Comments

  • Photo: James_M

    James_M commented on :

    This is actually an incredibly interesting question. The Earth has been sitting here for 4.5 billion years as a very long dark-matter experiment (10,000 years isn’t really long enough, but if you go to billions of years it gets interesting). The point is that whatever dark matter is it has been interacting (weakly) with Earth for all that time, possibly accumulating slowly. I have asked geologists I know if there would be a way to measure g Vs. time from rocks, but sadly they seemed to think it wouldn’t be possible. If you *could* do that measurement I think you could get a constraint on the mass and/or strength of interaction of dark matter.

    -James