Gloger.es@PARC-MAXC (12/19/82)
Did I miss something? Actually look what up?
If you just want to know how to compute gravitational tidal
gradients, you start with the unit standard astrophysics equation,
gravitational field strength = G*M/(d**2),
and you take the first derivative with respect to distance to get
the tidal effect,
tidal gradient = 2*G*M/(d**3).
And a quick check: The mass of the sun is 27 million times that
of the moon, while its distance from earth is 390 times that of the
moon. The above equation suggests that the sun's tidal effect at
the earth compared to that of the moon will be
27,000,000 / (390**3) = 0.45,
which is correct. It's because that specific result happens to come
out within a small factor of one that earth has its strange
dual solar/lunar tides.cjh@CCA-UNIX (12/29/82)
Would somebody care to actually look this up? The last time I investigated I was told that tidal influence varied as the \4th/ power of the distance.