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.

June 27, 1996
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.
Voyager's Preview of Galileo at Ganymede
Credit: Voyager Project, JPL, and NASA

Explanation: NASA's robot spacecraft Galileo began its long voyage to Jupiter in October of 1989. In December of last year it arrived in the Jovian system, beginning its unprecedented, detailed exploration by dropping a probe into the gas giant's atmosphere. By early this morning it will have accomplished another milestone in its ambitious mission. Now in orbit around Jupiter, Galileo will make its first close flyby of Ganymede, Jupiter's (and the solar system's) largest moon at 2:29 a.m. EDT. As planned, approaching to within 524 miles, it will make a series of high resolution images of the surface which will reveal features as small as 33 feet across. This close-up color image from the Voyager 2 flyby in 1979 previews sights Galileo will see in greater detail. Showing features as small as 3 miles across, it reveals a variety of terrain on Ganymede's icy surface, including impact craters with bright rays and long strips of light grooved structures suggesting large scale motions of the frozen crust. Galileo's flyby images will be stored onboard for playback and should be available during the week of July 10.

Tomorrow's picture: A Distant Galaxy in the Deep Field


| Archive | Index | Search | Glossary | Education | About APOD |
See Explanation.  Clicking on the picture will download 
 the highest resolution version available. See Explanation.  Clicking on the picture will download 
 the highest resolution version available. Top 5 logo See Explanation.  Clicking on the picture will download 
 the highest resolution version available.

Authors & editors: Robert Nemiroff (GMU) & Jerry Bonnell (USRA).
NASA Technical Rep.: Sherri Calvo. Specific rights apply.
A service of: LHEA at NASA/ GSFC