-
Comets are really balls of icy dirt which circle the Sun. When a Comet
comes nearer to the Sun, the heat melts some of the ice and a cloud is
created around the center of the comet.
-
Comets are not as common as meteors and most are too faint to be seen
without a telescope.
-
They have highly elliptical orbits that bring them very close to the
Sun and swing them deeply into space, often beyond the orbit of Pluto. Some Comets pass through the solar system only once, while others permanently orbit our system.
-
One of the main sources of Comets is the "Oort Cloud." The Oort Cloud
may surround the entire solar system. It may contain more than a trillion
comets orbiting the Sun.
-
Halley's Comet, last seen in 1986, is visible every 76 years. It will
be visible again in 2062.
-
There are many kinds of Comets, but all develop a cloud of diffuse material
called a coma, that usually grows in size and brightness as the comet approaches
the sun. Usually a small, bright nucleus is visible in the middle of the
coma. The coma and the nucleus together form the head of the Comet.
-
As Comets get closer to the sun, they develop huge tails of glowing
material that extend for millions of kilometers.
-
When Comets are further away from the Sun, the nucleus is very cold
and is frozen solid. In this state, they are called "Dirty Icebergs" or
"Dirty Snowballs" since over half of their material is ice.
-
In 1993, comet Shoemaker-Levy became trapped by the gravity of Jupiter
and plunged into Jupiter's atmosphere!
-
Some Comets, called Sungrazers, may actually crash into the Sun, or burn up because they are so close.
|
