Pluto and Charon as seen by the Hubble Space Telescope.
... or, rather, two moons.
Pluto and Charon as seen by the Hubble Space Telescope.
Pluto's mass is only 0.002 Earth masses and its radius is about 0.2 RE, or abut 2/3 the radius of the earth's moon. This gives it a density of about 2000 kg/m3, suggesting that it is made of ice and rock.
Its moon, Charon, has a radius about half that of Pluto.