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.

2000 July 21
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.

Eros Craters And Boulders
Credit: NEAR Project, JHU APL, NASA

Explanation: From a delicate orbit around asteroid 433 Eros, the NEAR Shoemaker spacecraft's camera has now imaged the entire surface of the small oddly-shaped world at least once. Recorded on July 7th from a distance of 50 kilometers, this dramatic view is about 1.8 kilometers across. It shows the walls and rims of two large overlapping impact craters on the horizon. Massive boulders which may be debris from the impacts are perched along the crater edges. The prominent boulder on the horizon near picture center is about 40 meters long. In fact, the NEAR mission to Eros has shown that along with craters and boulders, grooves and ridges are also common on the asteroid's surface. While the craters are clearly of impact origin, puzzles about the other surface features still remain. On July 13, controllers fired the spacecraft thrusters and moved NEAR Shoemaker to an even closer 35 kilometer orbit to enable higher resolution surface studies.

Tomorrow's picture: Gamma-Ray Sky

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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.