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You can’t really have a nice atmosphere with so little incoming solar radiation, and at 10g you’d be talking about a truly THICK atmosphere. Moons though, could
by QAPereo 9y ago
You can’t really have a nice atmosphere with so little incoming solar radiation, and at 10g you’d be talking about a truly THICK atmosphere. Moons though, could be “squeezed and stretched” from the gravitational interaction with the planet, but again they’d be coooooold. You’d have activity, but probably cryogenic volcanoes and the like.
- kijin 9y agoSurface gravity on a planet with 10 times the mass of Earth will not be 10g. The increased radius alone will reduce the surface gravity by a factor of 2 at least. But Planet 9 is also likely to be much less dense than Earth. Earth is the densest object in the solar system. You can't match our iron core with materials available in the outer reaches, so the surface will be even further away from the center. Surface gravity on Saturn is just around 1g (for a suitable definition of "surface"). Uranus is 0.9g. Neptune is 1.1g. Planet 9 is likely to be in the same ballpark if it's an ice giant.
- QAPereo 9y agoYou’ve confused radius and mass. 10x mass = 10x gravity, and then radius is a totally separate issue. Mass and surface gravity are proportional, while radius depends on issues of composition.
- kijin 9y agoSurface gravity absolutely depends on the radius. Gravitational force is proportional to mass and inversely proportional to the square of distance. Radius is the distance between the center of a planet and its surface. If this sounds wrong, please see the Wikipedia page for Saturn and explain how a planet with 95 times the mass of Earth is listed as having a surface gravity of only 1.065 g. (Actually, I was wrong above: the increased radius alone would reduce the surface gravity of this hypothetical planet by a factor of 4.6, not just 2, assuming Earth-like density.)