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Mapping Gravity

Posted by michael on from the slim-fast dept.

overThruster writes: "No, you don't need to drink the water... Gravity is less strong in India--enough so that you weigh almost 1% less there. See BBC story about NASA's gravity map." Here's another story about the mission, and the GRACE home page (or NASA's less-informative page).

1 of 194 comments (clear)

  1. Physics of it all by Simm0 · · Score: 5, Interesting

    You probably hear the 9.8 m/s^2 acceleration due to gravity touted but this is just the net affect across the whole of the globe which is actually very inaccurate when used at specific locations.

    Did you know that its actually easier to break the force of gravity ontop of mount everest. I'll show it using the formula:

    g = G*(m/r^2)
    = ((6.67*10^-11)*(5.98*10^24))/(6.389*10^6)
    = 9.77 m/s^2

    The value of g also can vary locally on the surface because of the presence of irregularities and rocks of different densities. Such variations in g also known as 'gravity anomilies'. Mineral deposits, for example, have a greater density than surrounding material; because of the greater mass in a given volume g can have a greater value on top of such a deposit then at its sides.

    Overall altitude, underground minerals and distance from the equator all play apart in changing the acceleration due to gravity across the globe.