• Question: How massive would something have to be to have a noticable force of gravity?

    Asked by astroaaron to Ben, Jony on 25 Nov 2011.
    • Photo: Jony Hudson

      Jony Hudson answered on 25 Nov 2011:

      It depends on how carefully you measure!!

      We have an experiment in the teaching lab at Imperial, that our first year students get to do, that measures the gravitation influence of a metal weight about the size of an apple. But to do that you need a very, very sensitive measurement device.

      [We use a torsion pendulum, see for instance:

      http://www.npl.washington.edu/eotwash/experiments/experiments.html%5D

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