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The Asteroid Belt

An avid camper and hiker as well as writer and astronomy lover, Jose Juan Gutierrez has always been inspired by the sky

The Asteroid Belt

The Main Belt

The asteroid belt, sometimes called the main belt, is situated between the orbits of Mars and Jupiter. this region is crowded with small rocky bodies called asteroids. The largest of these bodies: Ceres, Vesta, Pallas, and Hygiea have diameters larger that 400 km (248 miles). Temperatures in the asteroid belt range from 200 K (-163 F) at 2.2 astronomical units (AU) from the Sun to 165 K (- 226 F) at 3.2 AU from the Sun.

More than 200 asteroids are known to be larger than 100 km (62 miles) and over 1.5 million have diameters greater than 1 km (0.62 miles). The total mass of these objects is 4% the mass of the moon. Ceres, Vesta, Pallas, and Hygiea account for half of the asteroid belt´s mass, and Ceres, which is the largest asteroid in the belt, accounts for 1/3 of the total mass.

Types of Asteroids

Different Types of Asteroids

There are three types of asteroids in the asteroid belt: C type (carbonaceous), S type (Silicate), and M type (metallic) asteroids.C type asteroids are most commonly found in the outer region of the asteroid belt, and they account for 75% of the asteroid population. S type asteroids are very common, within 2.5 AU from the Sun, in the inner region. M type asteroids are distributed at approximately 2.7 AU from the Sun, between the type C and type S populations.

At 2.7 AU from the Sun lies a region known as the snow line, where temperatures lower down below the freezing point of water. In this region planetesimals (bodies big enough to attract other bodies in space) were able to accumulate ice. Comets have been discovered beyond the snow line. A small portion of asteroids may be burned-out comets, whose ices have gone through the process of sublimation, and then blown away into space. It is believed that Earth may have acquired sufficient water to form the oceans when comets from this region were knocked out of their orbits, sending them into the Earth´s atmosphere.

Zodiacal Light

The Zodiacal Light

Despite the great amount of asteroids in the main belt, they´re spread apart from one another. Spacecraft sent out into space have been able to transit through the asteroid belt without any problem. Collisions between asteroids 10 km (6.2 miles) in diameter are expected to occur once every 10 million years.

The asteroid belt contains very small particles of dust produced by collisions between asteroids. This dust in combination with the ejected material from a comet produces the zodiacal light which is the faint aurora glow extending from the direction of the Sun along the ecliptic.

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Asteroids might have modified Earth´s biosphere in the past and will continue to do so in the future; therefore, there is a high interest in asteroids. Asteroids contain rich sources of volatiles and minerals which can be exploited for exploration and colonization purposes in the 21st century.

© 2012 Jose Juan Gutierrez


Jose Juan Gutierrez (author) from Mexico City on January 15, 2012:

Maybe you mean "Van Allen Belt." The Van Allen Belt is a radiation zone surrounding the Earth, which is held in place by Earth´s magnetic field. Hope this answer your question.

somethgblue from Shelbyville, Tennessee on January 14, 2012:

Is there radiation in this asteroid belt and is this known as the Von Ryan or is that another asteroid belt?

Jose Juan Gutierrez (author) from Mexico City on January 11, 2012:

That´s what scientists predict will happen between asteroids that measure 10 km in diameter; one collision; once every 10 million years.

Rhys Baker from Peterborough, UK on January 11, 2012:

I didn't realise how infrequently asteroids collided. Thanks! Voted up and interesting.

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