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 August 24
See Explanation.  Clicking on the picture will download 
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Eros At Sunset
Credit: NEAR Project, JHU APL, NASA

Explanation: Gleaming in the rays of the setting sun, boulders litter the rugged surface of asteroid 433 Eros. The brightest boulder, at the edge of the large, shadowy crater near this picture's bottom centre, is about 30 metres (100 feet) across. In orbit around Eros since February 2000, the NEAR Shoemaker spacecraft's camera recorded the dramatic view earlier this month from an altitude of about 50 kilometres. Eros itself orbits the Sun with a perihelion of 1.13 Astronomical Units (AU) and aphelion of 1.78 AU. Part of a class of near-Earth asteroids, it spends much of its time between the orbits of Mars (at 1.5 AU) and Earth (at 1 AU) ... but it wasn't always that way. Eros and other near-Earth asteroids originally orbited in the main asteroid belt, between Jupiter and Mars. Over time, the gravitational influence of Jupiter and other planets perturbed their orbits sending them on trajectories closer to Earth.

Tomorrow's picture: Jovian Moon

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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.