History of Comet

Difference (from prior major revision) (minor diff)

Added: 14a15,16

Ironically, cometary nuclei are among the blackest objects known to exist in the solar system. The Giotto probe found that Comet Halley's nucleus reflects approximately 4% of the light that falls on it, and Deep Space 1 discovered that Comet Borrelly's surface reflects only 2.4% to 3% of the light that falls on it; by comparison, asphalt reflects 7% of the light that falls on it. It is thought that complex organic compounds are the dark surface material. Solar heating drives off volatile compounds leaving behind heavy long-chain organics that tend to be very dark, like tar? or crude oil. The very darkness of cometary surfaces allows them to absorb the heat necessary to drive their spectacularly bright outgassing.

Changed: 27c29

Sun - Mercury - Venus - Earth - Mars - Asteroids - Jupiter - Saturn - Uranus - Neptune - Pluto - Comets

	Revision 24 . . (edit) December 11, 2001 5:53 am by Bryan Derksen [bypassing venus link page]
	Revision 23 . . December 2, 2001 1:30 pm by Bryan Derksen [comets are the darkest things in the known solar system.]
	Revision 22 . . November 30, 2001 12:30 pm by Bryan Derksen [mention Deep Space 1's flyby of Comet Borrelly]
	Revision 21 . . (edit) November 24, 2001 10:33 am by Wayne Hardman
	Revision 20 . . November 24, 2001 10:29 am by Wayne Hardman
	Revision 19 . . (edit) November 5, 2001 9:16 am by Bryan Derksen [updated solar system navbar link to mars]