Discover the cosmos! Each day a different image or photograph of
our fascinating universe is featured, along with a brief
explanation written by a professional astronomer. 2001 October
15 Explanation: How similar in size are the Earth and the Moon?
A dramatic visual answer to this question is found by combining
photographs taken by the Mariner 10 spacecraft that headed out
toward Venus and Mercury in 1973. The Moon can be seen to have a
diameter over one quarter that of Earth, relatively large
compared to its planetary companion. In our Solar System, only
Pluto and Charon are closer together in size. Striking features
of the Earth visible to the passing spacecraft include blue
oceans and white clouds, showing the Earth to be truly a water
world. Authors & editors: Jerry Bonnell (USRA) NASA Technical
Rep.: Jay Norris. Specific rights apply. A service of: LHEA at
NASA/ GSFC & Michigan Tech. U.