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.
August 13, 1998
Explanation: While orbiting the planet during their June 1998 mission, the crew of the Space Shuttle Discovery photographed this view of two moons of Earth. Thick storm clouds are visible in the lovely blue planet's nurturing atmosphere and its largest artificial moon, the spindly Russian Mir Space Station, can be seen above the planet's limb. The bright spot to the right of Mir is Earth's very large natural satellite, The Moon. The Mir orbits planet Earth once every 90 minutes about 200 miles above the planet's surface or about 4,000 miles from Earth's centre. The Moon orbits once every 28 days at a distance of about 250,000 miles from the centre of the Earth.
Authors & editors:
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
&: Michigan Tech. U.