| MadSci Network: Physics |
In fact, as gravity depends upon the square of the inverse of the distance between the involved bodies, when you are in a deep mine, the gravity increases, because your center of mass is nearer the Earth's center of mass. The mean gravity variation with distance is about 0.3086 mGal/m, that is, as you move away 1 meter from the surface of the Earth the gravity decreases 0.3086 mGal (1 Gal = 1 cm/s2; 1 mGal = 0.001 cm/s2). Best regards Eder C. Molina Dept. of Geophysics Institute of Astronomy, Geophysics and Atmospheric Sciences University of Sao Paulo - BRASIL [note added by MadSci Admin: There are, in fact, some previous answers in our archives which discuss some of the more intricate details of this. Notable among them is the following answer: http://madsci.wustl.edu/posts/archives/jun2000/962116625.Ph.r.html You may find other previous answers by using our search engine and searching on, for instance, "earth gravity depth" ]
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