The Solar System is a vast expanse having the sun at the center and several astronomical objects surround it due to gravity. Scientists theorized that the Solar System was formed when a giant molecular cloud collapse leaving debris. The debris forms the objects in the Solar System- planets, moons, asteroids, meteoroids and comets.
Meteoroids
The International Meteor Organization defines the meteoroid as a “solid object moving in interplanetary space, of a size considerably smaller than a asteroid and considerably larger than an atom or molecule.” Meteoroids can be the debris from asteroid and comets.
Meteors
When meteoroids enter the Earth’s atmosphere, streaks of lights are visible in the sky. They are often referred to as “shooting stars”. Meteors travel at high speed that when the object crosses the atmosphere, the pressure releases energy and the glow of light is emitted. Most meteors vaporize when they hit the Earth’s atmosphere.
There is a phenomenon called a meteor shower where a number of meteors simultaneously enter the Earth’s atmosphere and illuminates the sky. This occurs when a comet leaves dust particles as it passes the sun. One of the most spectacular meteor showers is the Leonids meteor shower, remnant of the comet Tempel-Tuttle.
Meteorites
Meteorites are objects that survive when the meteoroid enters the Earth’s atmosphere. While most meteors vaporize, there are still a number of them that reaches the Earth’s surface. Meteorites can form craters as a result of the impact with the Earth. Meteorites may look like a regular rock. There may be dense chunks of metal along with it.
Comets
While meteors, meteors and meteorites are composed of rocks, comets are icy objects that are mixed with cosmic dust. A comet is composed of four parts: nucleus, coma, plasma tail and dust tail. As a comet passes the sun, the sun’s energy vaporizes the ice and the gas it releases forms a tail. Because of the sun’s illumination, some comets can be visible on Earth. Comets that are visible to the naked eye are called Great Comets. An example of a great comet is the Halley’s Comet which is visible from earth approximately every 75 years.
Meteoroids, meteorites, meteors and comets are celestials object that scientists and astronomers continue to study. These objects may be potential sources of raw material and resources.
Sources:
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Meteors
http://en.wikipedia.org/wiki/Meteoroid
http://curious.astro.cornell.edu/comets.php
http://library.thinkquest.org/23830/comets.htm
http://en.wikipedia.org/wiki/Comets
http://www.imo.net/glossary
