Saturday, February 06, 2016

[uhhgoemc] Large earth-like planet

Assuming material composition similar to earth, how large can a planet be before the increased gravity causes chemistry to become so different as to not be able to support earth-like life?  For example, oxygen becomes poisonous at higher density.

Removing the assumption of similar composition as earth, what is the least dense material that an earth-like planet could realistically be composed of, and how large could it then be?  This is a materials science question, probably very difficult due to the high pressures that will occur at the core.

Removing the assumption of naturally formed planet, how large could a constructed spherical world be and still able to support earth-like life on its surface?  We imagine it is mostly hollow to keep the density down, but with internal struts made out of realistic materials.  Of course, if we permit unrealistic superstrong superlight materials, then there is no limit in size.

How large could an O'Neill cylinder space station realistically be?  At large sizes, it probably wants to collapse on itself due to gravity.  Ringworld and the like require unrealistically strong materials against centrifugal force.

Inspired by fiction taking place on earth-like worlds with area larger than the earth, e.g., Minecraft.

No comments :