Actually there are several other natural bodies which, in some sense, orbit the Earth.
The Moon is the usual name for the single (see box at right) natural satellite of the Earth. The distance to the moon can be computed, surprisingly, from simply knowing the size of the Earth, acceleration due to gravity, and the orbital period.

It is about 384,400 km distant, and its diameter is about 3,475 km.

The Moon appears to make a complete orbit in about 29.5 days, but that is relative to the Sun. Relative to the stars the orbital period is around 27.3 days.

When the Moon moves into the shadow of the Earth we have a Lunar Eclipse.

Last change to this page
Full Page history
Links to this page
Edit this page
  (with sufficient authority)
Change password
Recent changes
All pages