The average period of the orbit of Halley's comet is 76 years, but the dates cannot be calculated exactly since the severity of the major planets alters the period of the comet at each turn. The Halley's orbit is retrograde and tilted 18 degrees from the ecliptic. And, like that of all comets, highly eccentric.
The nucleus of Halley's comet measures approximately 16 x 8 x 8 kilometers. The core of the Halley is very dark: its albedo is only 0.03, so it is blacker than coal and one of the darkest objects in the solar system.
The density of the Halley core is very low: about 0.1 grams / cm3, indicating that it is probably porous, perhaps due to the large amount of dust that remains after the ice sublime.
Halley is almost unique among comets, since it is both large and active, and has a regular and well-defined orbit. This makes it a relatively easy target for astronomers, although it is not the most representative of comets.
Halley's comet will approach the Sun again in 2061.
|◄ Previous||Next ►|
|Hale-Bopp Kite||Saturn photomontage|