World at the Edge of the Sun

    Mercury is a small world (4878 km in diameter) only 40 percent larger than our Moon. It orbits close to the Sun, a third closer than Earth and speeds through a year in just over 87 days. Mercury spins slowly on its axis, taking 58.6 days to turn once.

   Mercury has a surprising temperature range of -173 to 430 C. It also has a very high density of 5.44 g/cm3. It is not a world we would want to visit, nor one where life could be expected to survive.

  What we Learned from Mariner

 More About Mercury

Copyright © 1997 Kathy A. Miles and Charles F. Peters II