Mercury

From Wiki 5A

Mercury is a Terrestrial or Solid planet. Let's take a look inside Mercury. Inside Mercury is a core, mantle ,and a crust. The core was made of heavy materials, such as nickel and iron. These materials sank into the center where it became very hot. The process may still be cooled.

The mantle is the area surrounding the core. The mantle is made of lighter, rocky material. The thickness varies according to the temperature and pressure. Some planets like Earth have heat giving off by the cooling core. The crust is the small, thin outer layer of the planet Mercury. The crust may have cooled so quickly that the crust was almost distinct from its mantle. The outside of the planet Mercury looks like a moon. It is mostly covered with ancient craters. Mercury is not even one billion Kms away from the sun. Mercury is difficult to view with the naked eye. As Mercury moves around the sun, it rotates on its axis, an imaginary line that runs through its center. For result of the planet's slow rotation on its axis and rapid movement around the sun, a day on Mercury -- that is, the interval between one sunrise and the next -- lasts 176 Earth days.