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A moon with a sixth month period would be about 1.3 million km from Earth. That puts it close to the edge of the Earth's Hill sphere, and probably isn't stable in the long term. So the biggest thing you might notice is "goodbye moon" (and having the moon in an Earth crossing orbit wouldn't be pleasant in the longer term, a collision would melt the ...


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In general, tidal forces will cause the obliquity to decrease for an initially prograde rotation, so unless something is acting to disrupt the situation you would expect a tidally-locked satellite to end up with a very small obliquity. This is the observed rotation state of most of the major satellites in the Solar System. The Moon is something of a tricky ...


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gerrit's answer has done an excellent job of showing that (1) there are a narrow set of temperatures and pressures where liquid water exists and (2) a planet has to be pretty big to have enough gravity to keep water in the atmosphere. However, I wanted to mention this: However, the conditions required for liquid water can be extended by mixing it with other ...


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Do celestial objects need to be big to have liquid water on their surfaces? Yes. In a nutshell: liquid surface water needs an atmosphere. To sustain an atmosphere, a planet must be sufficiently massive, therefore sufficiently large. The warmer a planet, the more mass it needs to sustain an atmosphere. A planet warm enough for liquid water must thus also ...


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Liquid water can't exist in a vacuum. If there is no pressure, then the boiling point will drop to the freezing point and so there will either be ice or water vapour. And if the world is "small" then its gravity won't hold on to any water vapour, and it will be lost to space. The Earth can have liquid water because its gravity is strong enough to ...


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