Mercury
Mercury is the smallest planet in the Solar System and the
closest to the Sun. Its orbit around the Sun takes 87.97 Earth
days, the shortest of all the Sun's planets. Mercury is one of
four terrestrial planets in the Solar System, and is a rocky
body like Earth.
Source:
Wikipedia
Mercury appears to have a solid silicate crust and mantle
overlying a solid, iron sulfide outer core layer, a deeper
liquid core layer, and a solid inner core. The planet's
density is the second highest in the Solar System at 5.427
g/cm3 , only slightly less than Earth's density.
Source:
Wikipedia
Mercury's surface is similar in appearance to that of the
Moon, showing extensive mare-like plains and heavy cratering,
indicating that it has been geologically inactive for billions
of years. It is more heterogeneous than either Mars's or the
Moon’s.
Source:
Wikipedia
