See other Science/Tech Articles
Title: Comet Holmes Bigger Than The Sun
Source:
http://www.ifa.hawaii.edu/faculty/jewitt/holmes.html
URL Source: http://www.ifa.hawaii.edu/faculty/jewitt/holmes.html
Published: Nov 13, 2007
Author: David Jewitt
Post Date: 2007-11-13 09:08:17 by angle
Keywords: None
Views: 170
Comments: 5
Summary Formerly, the Sun was the largest object in the Solar System. Now, comet 17P/Holmes holds that distinction. Spectacular outbursting comet 17P/Holmes exploded in size and brightness on October 24. It continues to expand and is now the largest single object in the Solar system, being bigger than the Sun (see Figure). The diameter of the tenuous dust atmosphere of the comet was measured at 1.4 million kilometers (0.9 million miles) on 2007 November 9 by Rachel Stevenson, Jan Kleyna and Pedro Lacerda of the University of Hawaii Institute for Astronomy. They used observations from a wide-field camera on the Canada-France-Hawaii Telescope (CFHT), one of the few professional instruments still capable of capturing the whole comet in one image. Other astronomers involved in the UH program to study the comet include Bin Yang, Nuno Peixinho and David Jewitt. The present eruption of comet Holmes was first reported on October 24 and has continued at a steady 0.5 km/sec (1100 mph) ever since. The comet is an unprecedented half a million times brighter than before the eruption began. This amazing eruption of the comet is produced by dust ejected from a tiny solid nucleus made of ice and rock, only 3.6 km (roughly 2.2 miles) in diameter. Caption: (Left) Image of comet Holmes from the 3.6-meter Canada-France-Hawaii telescope on Mauna Kea showing the 1.4 million km diameter coma. The white ''star'' near the center of the coma is in fact the dust-shrouded nucleus. (Right) the Sun and planet Saturn shown at the same scale for comparison. (Sun and Saturn images courtesy of NASA's SOHO and Voyager projects). The new image also shows the growth of a tail on comet Holmes (the fuzzy region to the lower right in the comet picture), caused by the pressure of sunlight acting on dust grains in the coma. Over the next few weeks and months, the coma and tail are expected to expand even more while the comet will fade as the dust disperses. Comet Holmes showed a double outburst in November 1892 and January 1893. It is not known if the present activity in the comet will follow the pattern from 1892, but continued observations from Mauna Kea are planned to watch for a second outburst. Most comets show small fluctuations in brightness and some have distinct outbursts. The huge event on-going in comet Holmes is unprecedented, however. The orbit period of comet Holmes is about 6 years, putting it in the class of Jupiter Family Comets whose orbits are strongly influenced by Jupiter. These objects are thought to have spent most of the last 4.5 billion years orbiting the Sun beyond Neptune, in a region known as the Kuiper Belt. Holmes probably was deflected into its present orbit within the last few thousand years and is losing mass as it evaporates in the heat of the Sun. In another few thousand years it is likely either to hit the Sun or a planet, be ejected from the Solar system, or simply die by running out of gas. Contacts Rachel Stevenson [rach@ifa.hawaii.edu 808-956-6680] David Jewitt [jewitt@ifa.hawaii.edu 808-956-7682]
Post Comment Private Reply Ignore Thread
Top • Page Up • Full Thread • Page Down • Bottom/Latest
#1. To: angle (#0)
What is the mass of this comet?
To reason, indeed, he was not in the habit of attending. His mode of arguing, if it is to be so called, was one not uncommon among dull and stubborn persons, who are accustomed to be surrounded by their inferiors. He asserted a proposition; and, as often as wiser people ventured respectfully to show that it was erroneous, he asserted it again, in exactly the same words, and conceived that, by doing so, he at once disposed of all objections. - Macaulay, "History of England," Vol. 1, Chapter 6, on James II.
jewitt at hawaii.edu
Is that really blue? Or is that contrasting artistic license?
#2. To: aristeides (#1)
What is the mass of this comet?
#3. To: angle (#0)
 | “Before Isandwhlana we treated all your wounded men in our hospital. But when you attacked our camp your brethren, our black patients, rose and helped to kill those who had been attending on them. Can any of you advance any reason why I should not kill you?’ One of the younger men, with an intelligent face, asked, “May I speak?’ “Yes.’ “There is a very good reason why you should not kill us. We kill you because it is the custom of the black men. But it isn’t the white man’s custom." |
#4. To: angle (#0)
Damn! Undoubtedly related to the greedy-American caused Global Warming.
Republicans (Democrats for that matter) ....... HAD ENOUGH?
#5. To: angle (#0)
very cool, or hot as the case may be
Ron Paul for President - Join a Ron Paul Meetup group today!
Top • Page Up • Full Thread • Page Down • Bottom/Latest