Asteroid+Belt,+Kuiper+Belt

* Diameter: The largest objects are Ceres (1,003 km), Pallas (608 km) and Vesta (538 km). * Total Mass: The total mass of all the asteroids is less than that of the Moon. There are 26 known asteroids larger than 200 km across. * Location: The Asteroid Belt is a region between the inner planets and outer planets where thousands of asteroids are found orbiting around the Sun.
 * Area: The main asteroid belt extends from 255 to 600 million km (2.15 to 3.3 astronomical units) from the Sun and may contain over a million objects bigger than 1 km across.

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An asteroid is a bit of rock. It can be thought of as what was "left over" after the Sun and all the planets were formed. Most of the asteroids in our solar system can be found orbiting the Sun between the orbits of Mars and Jupiter. This area is sometimes called the "asteroid belt". Think about it this way: the asteroid belt is a big highway in a circle around the Sun. Think about the asteroids as cars on the highway. Sometimes, the asteroid cars run into one another. When this happens, the asteroids may break up into smaller asteroids. Scientists think that most asteroids are the result of collisions between larger rocky space bodies. Asteroids can be a few feet to several hundred miles wide. The belt probably contains at least 40,000 asteroids that are more than 0.5 miles across.

If an asteroid is captured by the gravitational pull of a planet, the asteroid can be pulled out of the belt and go into orbit as a moon around the planet that pulled on it. New observations from NASA's Spitzer Space Telescope indicate that the nearest planetary system to our own has two asteroid belts. Our own solar system has just one.

The asteroid belt is a region of space between Mars and Jupiter. It is generally called the main belt to distinguish it from the Kuiper belt and the scattered disc. The asteroid belt is so thinly populated that several unmanned spacecraft have been able to move through it – this isn’t the dense field of asteroids you see in movies and television. The next mission to pass through the asteroid belt will be the Dawn space mission. The first spacecraft to make a journey through the asteroid belt was Pioneer 10 in 1972. There have been a total of 12 missions that have made it through the belt. The asteroid belt has many mysteries. Although there are many things that are known about the belt, there hasn’t been much exploration. The Dawn space mission will change all of that in the next few years. Many of the things that are currently known come from meteorites that have fallen to Earth. Perhaps we will learn more if we ever decide to try to mine asteroids

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 * The total weight of all the asteroids in the asteroid belt is about 1/35th of that of our moon!
 * The largest asteroid, called Ceres, makes about 1/3 of the total weight of all the asteroids!
 * Are there asteroids outside of the asteroid belt? **
 * Most asteroids are found in the asteroid belt, but not all. Some asteroids orbit closer to the Sun. Asteroids that closely approach Earth are called Near-Earth Asteroids. Sometimes they strike the Earth, burning in the atmosphere as a meteor. If they are large enough, they might actually hit the surface and become meteorites.
 * There are also some asteroids in the outer solar system that are called Centaurs, although it is hard to determine whether a particular Centaur is an asteroid, comet, or Kuiper Belt object. For example, the first Centaur to be discovered was Chiron. But some scientists think it is a comet, not an asteroid. Officially it is both the asteroid 2060 Chiron and the comet 95P/Chiron!
 * Some asteroids are also found at the stable point’s 60Â° behind and ahead of the orbits of Jupiter and other planets. The points are called Lagrange points and the asteroids found there are called Trojans. Many of the small moons of some planets may have once been asteroids that were captured by the planet's gravity when they came too close.

The Kuiper belt extends from Neptune's **orbit** to three billion kilometers beyond it. It contains lumps of icy material with **organic compounds**. That makes them like **comets**. These lumps are called Kuiper belt objects or minor planets. The Kuiper belt may have formed when the gravity of the young Jupiter sent the Kuiper belt objects out to where they are now.
 * Kuiper Belt Facts **:
 * The Kuiper belt is the most recently observed section of the Solar System.

How big are the Kuiper belt objects?
Scientists consider Pluto to be one of the largest Kuiper belt objects. It is 2390 km across. The next largest known Kuiper belt objects are Orcus, which is about 1600 km (1,000 miles) across, 2003 EL61 at 70% the size of Pluto and 2005 FY9 at 50% to 70% of Pluto's size. Recently, scientists found an object, 2003 UB313, that is bigger than Pluto. The scientists don't know its exact size, but the estimate it is about 20% larger than Pluto. At the time it was discovered, it was almost 100 times further away from the Sun than Earth is. It can come about as close to the Sun as Pluto is. Its orbit is tilted almost 45 degress compared to Earth's orbit. Pluto's orbit is tilted by only 17 degrees. Some people are calling it the tenth planet. Others don't think that 2003 UB313 is a planet and don't think that Pluto should be considered one either. Other large Kuiper belt objects about or over 1000 km across are Pluto's moon Charon, Quaoar, Varuna, Ixion, 1996 TL66, 2002 TX300, 2002 TC302, 2002 UX25 and 2002 AW197. Ceres, the largest **asteroid**, is about 950 km across. There are many other Kuiper belt objects that are only a few kilometers or tens of kilometers across.

How many Kuiper belt objects are there?
By the year 2004, over 800 Kuiper belt objects had been found. Scientists think that there are many more yet to be discovered, and some might be as big as Earth (though much colder).

What is it named after?
After the first object in the belt was spotted from the Mauna Kea Observatory in Hawaii, the belt was named after the astronomer Gerard Kuiper, who, in 1951, wrote that he thought it had existed very long ago. Astronmomers including Frederick Leonard, Kenneth Edgeworth, and Julio Fernandez thought that the belt still existed; and some astronomers call it the Edgeworth-Kuiper belt.

What are the Kuiper belt objects named after?
When an object is discovered in space, it is given a temporary name called a "provisional designation". This temporary name begins with the year the object was discovered, followed by some letters and numbers that tell in what month and in what order it was discovered. Later on, important objects are given other names, often from mythology. Orcus, Charon, and Varuna were named after mythological gods of the underworld. Ixion was named after a mythological person in the underworld. Quaoar was named after a creation god of the Native American Tongva people. []

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 * The Asteroid Belt lies between the orbits of Mars and Jupiter.
 * The asteroids are also called minor planets and are irregularly shaped.
 * A fifth planet could have formed in this region, but Jupiter's massive gravitational pull stops this from happening.
 * The asteriods are composed primarilyy of rock and range in size from dust particles to about 590 miles across.
 * A few asteroids have moons of their own.
 * If all of the asteroids in the belt were lumped together, it would be smaller than Earth's moon.
 * This belt is not like the asteroid fields in movies; these asteroids are very far apart.
 * Ceres, the largest object in this region, now qualifies as a dwarf planet like Pluto.

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 * __Carbonaceous asteroids__**= These are common, stoney, and very dark, like coal.
 * __Silicaceous asteroids=__** These can contain metal, and are very bright and stoney.
 * __Metallic asteroids=__** These could possibly be the cores of much larger bodies.

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