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0 pointswheels2y ago0 comments

Gravity is only about 1.25 g, according to Wikipedia. Density matters. The earth and Saturn have about the same surface gravity.

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OkayPhysicist2y ago

Comparing rocky planets, density doesn't really matter at all. The range of possible densities for rocky planets is tightly constrained. What matters is the fact that surface gravity scales sub-linearly with regards to a planets mass.

  M = 4/3*pi*r^3*d
  r = (4/3*pi*d/M)^(-1/3)
  a = GM/r^2
  a = GM(4/3*pi*d/M)^(2/3)
  a = G(4/3*pi*d)^(2/3) * M^(1/3)

wheelsOP2y ago

We know that it's not (primarily) rocky though because the radius is 2.6 that of earth, but the mass is only 8 times. So it's about about 46% as dense as earth.

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OkayPhysicist2y ago

  M = 4/3*pi*r^3*d
  r = (4/3*pi*d/M)^(-1/3)
  a = GM/r^2
  a = GM(4/3*pi*d/M)^(2/3)
  a = G(4/3*pi*d)^(2/3) * M^(1/3)

wheelsOP2y ago

We know that it's not (primarily) rocky though because the radius is 2.6 that of earth, but the mass is only 8 times. So it's about about 46% as dense as earth.

j / k navigate · click thread line to collapse