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.

January 20, 1997
See Explanation.  Clicking on the picture will download 
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Earth Nears Asteroid Toutatis
Credit: E. De Jong and S. Suzuki, JPL, NASA

Explanation: On November 29, 1996 the Earth came within 3.3 million miles of the asteroid Toutatis. Above is a computer simulated picture of this spectacle from the surface of Toutatis (a 2.5 degree field of view looking toward Earth). In Earth's sky, Toutatis appeared only as a faint object moving against a background of stars. Also known as Earth-crossing asteroid 4179, Toutatis is in an eccentric 4 year orbit which moves it from the asteroid belt between Mars and Jupiter to just inside Earth's orbit. When the Earth passed near it in 1992 Toutatis was imaged by radar and seen to be two irregularly shaped lumps, perhaps joined by a narrow neck. This bizarre object is up to 1.5 miles wide, 2.9 miles long, and is tumbling through space. In the year 2004, on September 29, the Earth will pass very near Toutatis, closing to within a million miles (4 times the Earth-Moon distance) - the closest approach predicted for any asteroid or comet between now and 2060. Studies of Toutatis and other Earth-crossing asteroids help reveal connections between the Solar System's meteorites,main-belt asteroids and comets. These wayward asteroids also offer tantalizing targets for robotic exploration and, over time, represent potential collision hazards for planet Earth!

Tomorrow's picture: Journey to the Center of the Galaxy

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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.