Astronomy Picture of the Day

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.

October 22, 1996

The Cracked Ice Plains of Europa
Credit: Galileo Project, JPL, NASA

Explanation: What caused the cracks in this giant ice-ball? Jupiter's moon Europa has smoothest surface in the solar system and is composed mostly of cracked water-ice. In the above false-coloured picture released last week by the NASA team in charge of the Galileo mission, blue hues represent ice plains divided by dirty red and brown bands of mottled terrain. As the robot Galileo spacecraft orbits Jupiter, it sends back revealing pictures of Jupiter and its large moons including Europa, Io, Ganymede, and Callisto. The region of Europa highlighted above is known as Minos Linea. The cause for many of the cracks remains unknown but may involve shifting stresses from gravity and temperature variations. The new Galileo pictures have increased evidence that liquid oceans may indeed exist under these giant ice-sheets, a place possibly ripe for the development of life.

Tomorrow's picture: The Large Cloud of Magellan

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
&: Michigan Tech. U.