> The OP could start here:
>
> http://en.wikipedia.org/wiki/Planetary_habitability
OK, I did so...
Short answer. 0.3 earth masses is required to keep an atmosphere more
or less.
Models based on how large is needed for Plate Techtonics vary, with
the possibility the Earth is at a sweet spot in terms of enough energy
to break the crust, but not with such a thick crust it can't be
broken.
Info at http://en.wikipedia.org/wiki/Super-Earth as well.
What I can't find is whether a planet with a core lat Neptune's at the
distance from the Sun that the Earth is would necessarily keep all of
the Hydrogen that Neptune did. (balance between mass and solar wind).
Hmm. Maybe we can do a world where not only was Columbus right as to
where Japan was, the world doesn't have plate tectonics. :)
Randy |
