# Tag Info

## New answers tagged planets

2

Your equation is incorrect. The gravitational potential is $$\phi(r)=-GM\frac{3a^2-r^2}{2a^3}$$ when you're inside a uniform sphere of radius $a$ with total mass $M$. This is a quadratic potential in $r$, which is why it gives rise to harmonic exchange of energy when you oscillate between the planet surface and the core.

0

Part of the IAU definition of a planet is that it "has 'cleared the neighbourhood' around its orbit". So, you can only have a single planet at a particular distance from its parent star as a matter of definition. Otherwise, it wouldn't be a planet.

7

I posted an answer to a similar question here: http://physics.stackexchange.com/a/97978/1255 The wording there was pretty much asking for a broad description of the physics (which come down to bifurcation possibilities) up to, and including, the topology changes of the planet. The paper I linked to seems to be pretty much the state of the art on this ...

1

You can't see the sky from Venus surface. In fact, if you look it with a telescope, you will see only clouds. There are very few images of its surface in deed, just retrieved in 1982 by the Venera 13 module. So, I guess the effect is that is cloudy... permanently. source: here, quote from the first paragraph: The Venusian atmosphere supports opaque ...

6

When an object comes within the Roche limit, it breaks up because of tidal stresses - the part closest to the earth feels a stronger gravitational attraction than the furthest part. Hence, the closest part will fall a little faster than the trailing parts. As a result, "disintegration" does not mean that the body will fly apart like a bomb. Instead, it ...

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