home *** CD-ROM | disk | FTP | other *** search
- Comets seem to originate in the outer regions of the solar system, well beyond the orbits
- of Pluto and Charon. Some evidence suggests that there may be another large planet
- more distant than Pluto, but such a body has not yet been found.
-
- Short period comets may come from the Kuiper belt, a disc of cometary material just
- beyond Pluto. However, it is generally believed that most comets originate in the Oort
- Cloud, a mass of frozen particles and chunks surrounding the solar system at a distance of
- about one light-year. This is roughly equal to 5 quadrillion, 920 trillion miles from the
- Sun.
-
- A comet is a small member of the solar system, moving around the Sun in an orbit which
- is generally highly elliptical. The orbits of comets often bring them close to the Sun,
- passing near the inner planets, before being flung out into deep space again. Some short
- period comets never venture far beyond the orbit of Jupiter. Many other deep space
- comets travel as far as a light year away.
-
- Comets, composed mostly of ice, dust, and gas, are very important objects of study.
- Comets contain large amounts of water and complex hydrocarbons, the materials that
- created life on Earth. The ancient materials frozen inside of comets may contain the
- answers to the origins of the solar system, and of life itself.
-
- Asteroids, like comets, are minor bodies in the solar system. However, most of the
- asteroids in the solar system exist in the Main Asteroid belt, located between the orbits of
- Mars and Jupiter. It is likely that the powerful gravitational pull of Jupiter prevented the
- main asteroid belt from becoming a full planet.
-
- There are different varieties of asteroids. Some are made of rock and minerals, and others
- contain metals. Nearly all of the materials to be found in asteroids would be useful for
- human industry. Perhaps someday we will utilize these huge reserves of raw materials.