Comets are small Solar System bodies that are caught in the Sun's orbit. When a comet is close to the sun they exhibit a visible coma, otherwise known as a tail, which effects the solar radiation from the comet's nucleus. Comet nuclei are made up of loose collections of ice, dust, and small rocky particles.

The orbit of a comet ranges from a few years to hundreds of thousands of years. Some comets flow through the Solar System once before being thrown out into interstellar space. Short period comets are thought to be created in the Kuiper belt (which is associated with the scattered disc) while long period comets originate at a great distance from the sun, perhaps in the Oort cloud. These comets are thought to be made of debris left over from the condensation of the solar nebula. Comets are thrown into the inner solar system by the gravitational push of other stars.

The trail of debris following comets is what shows as a comet's path crosses the earth's path. A meteor shower occurs every year between August ninth and thirteenth when the Earth passes through the orbit of the comet Swift-Tuttle. Halley's Comet causes the Orionid shower in October.

Comets are easily distinguished from asteroids by the presence of the comet tail, also known as a coma. However, very old comets may have lost all of their volatile materials that cause a coma and may eventually resemble asteroids. Asteroids are suspected to form in the inner Solar System, rather than the outer Solar system.

As of June 2008 there were 3475 known comets reported. Several hundred of these comets appear to be short period comets. However, the number of comets appear to be steadily increasing. This number does represent a small amount of the total potential comet population.



Article Source: http://EzineArticles.com/?expert=Alexander_Sutton

Orion's Belt is part of a larger constellation called The Hunter. Orion is a very prominent and popular constellation, perhaps being the best-known and most conspicuous constellation in the sky. Orion's three "belt" stars are found on the celestial equator and are visible throughout the worlds. The three belt stars are of medium brightness and are the medium part of the constellation. In mid-northern latitudes, the constellation is visible in the evening from October to early January, and in the morning from lat July to November.

Orion is not the only name for The Hunter. In Australia the belt and sword of Orion are sometimes called the Saucepan. It is called the Drie Konings (Three Kings) by Afrikaans and Trois Rois (The Three Kings) by the French. Both of these names are founds in 17th and 18th century seaman's guides. Historically it is also referred to as Babylonian "Shepherd of Anu."

Orion's Belt was configured roughly 1.5 million years ago due to the relatively slow movements of the stars within the constellation. Orion is estimated to remain visible for the next one to two million years. This makes it one of the longest observable constellations parallel to the rise of human civilization.

Because of the correlation between Orion's age and the birth of human civilization, Orion is recognizable throughout mythology. The three stars of Orion's Belt were at one point associated with Osiris, the god of death and the underworld by the ancient Egyptians. Sumerians saw this patter as part of a shepherd or chariot while in China Orion was on e of the twenty eight lunar mansions.

References in the ancient Middle East were to the best and sword, which echoes throughout modern western literature.



Article Source: http://EzineArticles.com/?expert=Alexander_Sutton

The Solar System consists of the sun and the celestial objects bound by its gravity.

These planets include Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. At one point Pluto was also considered the ninth of Sun's Solar System, until it was later defined as a moon capable of its own gravity pull. The moon also pulls the planet's 166 moons and four dwarf planets in its gravity.

When broadly describing the Solar System and its region, it is easiest to consider the solar system's largest bodies, the Sun, four terrestrial inner planets, the asteroid belt, four gas giant outer planets, the Kuiper belt, the scattered disk and the hypothetical Oort Cloud.

A solar wind permeates the Solar System, made of charged particles from the sun. This solar wind creates the heliosphere, which is separated from the rest of the solar system by the heliopause located around the scattered disk.

The sun is the main component of the Solar System, which every other part of the Solar System revolves around. The sun contains 99.86 percent of the Solar System's known mass. Jupiter and Saturn account for 90 percent of the remaining mass of the Solar System.

A large majority of the objects in the Solar System lie near Earth's orbit, which is known as ecliptic. The planets are very close to ecliptic while comets and the Kuiper belt are usually at different angles to it. The planets orbit with the Sun's rotation, which is counter clockwise, with a few exceptions such as Halley's Comet.

Every body in the Solar System varies in the distance from the sun throughout the course of its year. The closest approach to the sun is called perihelion, while the largest distance from the sun is referred to as its aphelion.


Article Source: http://EzineArticles.com/?expert=Alexander_Sutton