Why Comets Are Important - NASA Solar System Exploration
2000年6月7日 · When a comet approaches within a few Astronomical Units (1 AU equals approximately 150 million kilometers) of the Sun, the surface of the nucleus begins to warm, …
In Depth | 1P/Halley – NASA Solar System Exploration
Comet Halley moves backward (opposite to Earth's motion) around the Sun in a plane tilted 18 degrees to that of the Earth's orbit. Halley's backward, or retrograde, motion is unusual among …
Asteroids, Comets & Meteors - NASA Solar System Exploration
Don’t let the name fool you. Our solar system’s small bodies – asteroids, comets, and meteors – pack big surprises. These chunks of rock, ice, and metal are leftovers from the formation of …
In Depth | C/1995 O1 (Hale-Bopp) - NASA Solar System Exploration
Also called the Great Comet of 1997, comet C/1995 O1 (Hale-Bopp) is a large comet with a nucleus measuring approximately 37 miles (60 kilometers) in diameter. This is about five times …
Stardust - NASA's Comet Sample Return Mission - NASA Solar …
The primary goal of the Stardust mission was to collect samples of a comet and return them to Earth for laboratory analysis. Comets are ancient bodies of frozen ice and dust that formed …
In Depth | 2P/Encke – NASA Solar System Exploration
Comet Encke has the shortest orbital period of any known comet within our solar system. Encke last reached perihelion (closest approach to the sun) in 2015. Comet Enke is the parent comet …
Comet Shoemaker-Levy 9 - NASA Solar System Exploration
On the night of March 24, 1993, Eugene and Carolyn Shoemaker and David Levy discovered a strange looking comet from a photograph taken from the 0.4 meter Schmidt telescope in …
In Depth | C/2012 S1 (ISON) – NASA Solar System Exploration
C/2012 S1 (ISON) was the subject of the most coordinated comet observing campaign in history. Over the course of a year, more than a dozen spacecraft and numerous ground-based …
In Depth | Stardust – NASA Solar System Exploration
1999年2月7日 · Stardust, now known as Stardust/NExT, flew by Tempel 1 at 04:42:00 UT Feb. 15, 2011, at a range of 112 miles (181 kilometers), returning 72 images of the nucleus. This …
Comet Shoemaker-Levy Home Page (JPL) - NASA Solar System …
From July 16 through July 22, 1994, pieces of an object designated as Comet P/Shoemaker-Levy 9 collided with Jupiter. This is the first collision of two solar system bodies ever to be observed, …