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 10
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.

Comet LINEAR Extends
Credit & Copyright: Bob Yen (Comet-Track)

Explanation: Comet LINEAR's tail appears to be extending. Many sky watchers are closely following Comet C/1999 S4 LINEAR and wondering if it will develop an impressive tail or become visible to the naked eye later this month. So far, the unpredictable comet is moving oddly indicating that exploding caverns of heated gas are causing the comet to shift slightly in its orbit around the Sun. This volatility contributes to Comet LINEAR newly visible two-degree tail, discernable in the above photographic negative taken Friday from California. Current brightness estimates indicate that Comet LINEAR will just barely become visible without binoculars in northern skies in the days surrounding July 23 during the early evening hours.

Tomorrow's picture: A Crab in Blue and White

< | Archive | Index | Search | Calendar | Glossary | Education | About APOD | >

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.