What are the requirements for an atmosphere retaining moon with a stable orbit around an Earth-like planet with non-destructive tidal forces?

For story writing purposes I would like a realistic setup where there is a planet with close to earth conditions in terms of gravity, relative position to the sun etc. However I aim to have a much larger moon with greater mass and thus a gravity sufficient to retain an atmosphere. This leads to questions of wicked harsh tidal forces on the planet.

I plan to solve the destructive tidal forces issue by moving the moon further away. This seems to be the prevailing wisdom and makes a lot of sense. However I am concerned about a sufficiently large moon breaking orbit (which my limited understanding of such things suggests would happen) and would need to work out (1) how large the moon might look from the planet's surface (2) what the tides would be like and (3) what sort of flight times between the two there might be.

I imagine that the moon would look larger, that flight times would be greater but the difference would be trivial and that the tides on the planet would be harsh on the coast while the tides on the moon would be calm (is that right?)

I am not looking for earth-like tides, they can be harsh as long as they do not make inland habitation pointless planetside.

I don't especially want to end up with a planet which is many multiples that of earth's size or gravity (up to 1.1g would be fine).

My grasp of some of the more advanced maths is limited at best so layman's terms explanations would be appreciated along with the hard science.

posted almost 9 years ago

Matthew Brown aka Lord Matt‭

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