asteroids
Asteroids are small, rocky objects that orbit the sun. Although asteroids orbit the sun like planets, they are much smaller than planets.
Asteroids hang out in other places, too. For example,
some asteroids are found in the orbital path of planets.
This means that the asteroid and the planet follow the same
path around the sun. Earth and a few other planets have asteroids like this.
The majority of the known asteroids in the Solar System orbit the Sun in a band between the orbits of Mars and Jupiter. This band is commonly referred to as the Asteroid Belt.
Although there are hundreds of thousands of asteroids in the Asteroid Belt, there are only around 200 known that exceed 100 km in diameter, making the majority of the asteroids realtively small objects.
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Asteroids are small, rocky objects that orbit the Sun.
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The first asteroid was Ceres, discovered by Giuseppe Piazzi in 1801.
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There are currently over 600,000 known asteroids in our solar system.
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Most asteroids are found orbiting in the Asteroid Belt, a series of rings located between the orbits of Mars and Jupiter.
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Astronomer William Herschel first coined the word asteroid, which means “star like” in 1802.
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As well as being the first asteroid discovered, Ceres is also the largest known asteroid at 933 kilometers (580 miles) across. The smallest known asteroid, 1991 BA, is only 6 meters (20 feet) across.
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Current theory suggest that asteroids are planetisimals – the building blocks of planets – that were never incorporated into one of the eight planets in our solar system.
These images show several views from a radar-based computer model of asteroid 216 Kleopatra. The object, located in the main asteroid belt between Mars and Jupiter, is about 217 kilometers (135 miles) long and about 94 kilometers (58 miles) wide, or about the size of New Jersey. This dog bone-shaped asteroid is an apparent leftover from an ancient, violent cosmic collision. Kleopatra is one of several dozen asteroids whose coloring suggests they contain metal.
An illustration of the asteroid 24 Themis along with two small fragments that orbit with it. One of the small fragments is inert (as most asteroids are) and the other has a comet-like tail, produced by the sublimation of water ice from its surface. Scientists announced the first discovery of water ice on 24 Themis
1862 Apollo is the prototype asteroid of the Apollo group. It was discovered by the German astronomer Karl Reinmuth (1892–1979) in 1932, when it approached Earth to within 10.5 million kilometers (0.07 AU), but was then lost until 1973. Apollo can come as close to Earth as 4.2 million kilometers (0.028 AU) and also make near passes of Venus and Mars, whose orbits it crosses at perihelion and aphelion, respectively.
These images show several views from a radar-based computer model of asteroid 216 Kleopatra. The object, located in the main asteroid belt between Mars and Jupiter, is about 217 kilometers (135 miles) long and about 94 kilometers (58 miles) wide, or about the size of New Jersey. This dog bone-shaped asteroid is an apparent leftover from an ancient, violent cosmic collision. Kleopatra is one of several dozen asteroids whose coloring suggests they contain metal.