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.

March 25, 1996

Comet Hyakutake Passes the Earth
Credit and Copyright: Peter McCullough (U. Illinois Urbana-Champaign)
McCollough's MPEG Movie of Comet Hyakutake taken March 23

Explanation: This picture of Comet Hyakutake taken the night of March 21/22 in Illinois, USA shows the enormous tail that has already developed. The silhouette on the right is a foreground tree, and the superposed green circle on the left shows the size of the full moon. Today Comet Hyakutake makes its closest approach to the Earth. As the comet moves into the inner Solar System, it will pass the Earth at about 40 times the distance of our Moon. This is not the closest a comet has ever come, though. As recently as 1983 Comet IRAS-Araki-Alcock came three times closer than Hyakutake, and in 1770 Comet Lexell got yet twice closer than that! Asteroids - usually less massive than comets - frequently whiz by inside the Moon's orbit, with four doing so far in this decade. In the distant past, asteroids have even struck the Earth. Comet Hyakutake is much brighter now than Comet IRAS-Araki-Alcock ever got, and in fact is the brightest since Comet West in 1976. Comet Hyakutake will be easily visible all week.

Latest Comet Hyakutake images: JPL,

Tomorrow's picture: What are Comet Tails Made Of?

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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.