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mfb is offline
Nov24-12, 04:28 PM
P: 10,836

Is g affected by other sources of gravity?

To add some numbers:

Earth: ~9.81 m/s^2
Sun (average): 0.0059 m/s^2
Moon (average): 0.000033 m/s^2
Jupiter at closest approach: 3.7*10-7 m/s^2 = 0.00000037m/s^2
Venus at closest approach: 2.3*10-7 m/s^2

But: Those forces are very uniform throughout earth. You cannot measure an absolute acceleration - only a difference between two points (here: earth and you). This changes numbers a lot:
Earth: ~9.81 m/s^2
Moon (average): 6*10-7 m/s^2
Sun (average): 3*10-7 m/s^2
Venus at closest approach: 4*10-11 m/s^2
Jupiter at closest approach: 4*10-12 m/s^2
And just for fun:
Proxima Centauri (closest star): ~10-23 m/s^2
1000 kg in a distance of 2m: ~2*10-8 m/s^2

Best relative gravimeters according to Wikipedia article: ~10-11 m/s^2 (at least within some hours of measurement: source, pdf)