Rocky

Mercury

A small rocky world with a heavily cratered surface and a very thin exosphere.

Mean orbital distance (AU)

0.387

Mean diameter (km)

4879

Orbital period (Earth days)

87.97

Planet class

Rocky

Understanding this entry

Its large metallic core occupies an unusually large fraction of the planet.

Further reading and reference: Topic reference ↗. Values and educational summaries are not a substitute for specialised advice.