Skip to comments.Astronomy Picture of the Day 8-02-02
Posted on 08/01/2002 10:54:25 PM PDT by petuniasevan
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.
2002 August 2
Explanation: Comet 57P has fallen to pieces, at least 19 of them. Orbiting the Sun every 5.9 years or so this faint comet - also christened Comet 57P/du Toit-Neujmin-Delporte for its three 1941 co-discoverers - is simply 57th on the list of comets known to be periodic, beginning with Comet 1P/Halley. In mid July, responding to reports of a new object possibly associated with Comet 57P, astronomers were able to construct this mosaic of deep sky images identifying a surprising 19 fragments (circled) strung out behind the cometary coma and nucleus itelf (far left). The full mosaic spans about a million kilometers at the distance of the comet, while the individual pieces detected are probably a few tens to a few hundred meters across. Stress produced as sunlight warmed the icy, rocky nucleus likely contributed to the fragmentation. In fact, when last seen passing through the inner solar system in 1996, Comet 57P brightened unexpectedly, indicating a sudden increase in surface activity.
Comets seem to be somewhat loose conglomerations of rock and ice. "Dirty snowballs" is a good description. Solar radiation absorption varies over the comet's surface (darker rock absorbs more than lighter ice) may cause uneven heating at a rapid pace, which may cause such fragmentation as we see in today's APOD. Another way to break up a comet is to let the Sun or Jupiter's tidal effects do the trick (remember comet Shoemaker-Levy 9?)
Get on the APOD PING list!
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.