Re: Planetary gravity question.

> I fear not. Earth's density is about 5.515 g/cm^3 - about the same
as
> iron, because it has an iron core. Fair enough. This hypothetical
planet
> would have a density of about 20.2 g/cm^3 (radius x density is
constant
> for constant surface gravity, radius of moon is about 1737.5km,
radius
> of Earth is about 6371.01km).
>
> For reference, pure gold has a density of 19.32 g/cm^3; platinum is
> 21.3; iridium is 22.16. Within reasonable error tolerances, we're
> looking at a solid lump of precious metals 2,000 miles across.

Or  a more normal planet with a small neutronium core.	Or put a black
hole in the center.  Depends, as always, on how much Science you want
in your Pseudo Scientific Blarney.