Did u ever watch "Deep Impact" ???Or "Armageddon" ??? I think u ever watched it...So exclaimed,right ???. The movie story about the asteroids that will hit earth...Could u imagine when an asteroid hit Earth ???It will be a big big big disaster,the "dooms day"...Because of this ,the dinosaurs was extincted.
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| Asteroid Belt |
Asteroid(planetoid also minor planet) is rock that orbiting the sun. Asteroid placed in the Asteroid belts,where between Mars and Jupiter. There are many asteroid with different size, beginning from 1 km diameter size until 1000km (Ceres,the biggest) . The asteroids amount in our solar are about 1million. Over 8,000 of these have been individually cataloged and named, and have well-determined orbits. Although it is common to depict the asteroid belt as a dense region, asteroids are actually quite well separated, rarely approaching within 1 million km of one another. (A few asteroids have moons of their own: these are certainly the exception to the rule.) All together, the asteroid belt contains about 0.1% of the mass of the Earth. Earth mass is about 5.98 x 10 24 kg. So it is 5.98 x x 10 21 kg
In addition to the asteroids in the belt, some asteroids share Jupiter’s orbit. Asteroids in this special group are called Trojan asteroids, and they orbit about 608 ahead or behind Jupiter. Their orbits are stabilized by the combined gravity of Jupiter and the Sun. Over 150 of these are known; the largest is about 300km in size.
Astronomers estimate that the asteroid was created the same time as our solar system. They are byproduct. As theory said that planets formed by the joining of the asteroids. Asteroids on the Asteroid belt is the rest of solar system material when was created. They have stable gravitional in there.
Finally, some asteroids are ‘‘Earth-crossing’’ and are potential impactors. These asteroids come from three different groups—the Apollo, Aten, and Amor asteroids. Most of these are small, less than 40km across, and so they are difficult to find in the sky. About 500 are known. Most of these will strike the Earth some time over the next 20–30 million years. Near-misses are common, and are often unpredicted. In 1990, an asteroid came closer to the Earth than the Moon. The asteroid was previously undiscovered, and was not noticed until after it had safely passed the
Earth.
Asteroids do not emit visible light, they only reflect it. Astronomers determinethe compositions of asteroids by comparing the spectrum of the light reflected by the asteroid and the spectrum of the Sun. Absorption lines that are present in the asteroid’s spectrum, but not in the solar spectrum, must be due to elements or minerals in the asteroid. Asteroids are classified in three major groups: carbonaceous (C), silicate (S), and metallic (M). Most asteroids are C-type asteroids, with very low albedo and no strong absorption lines. The rest are mainly S type, with an absorption feature due to a silicate mineral, olivine.
The amount of light reflected from an asteroid towards the Earth changes as the asteroid tumbles through space. We can use this information to determine how quickly the asteroids rotate. About 500 asteroids have been studied well enough to determine their rotation periods, which are generally between 3 and 30 hours.
Smaller asteroids have irregular shapes. The shape of small asteroids can be determined from analysis of the amount of radiation received over time (light curve).
Source : http://en.wikipedia.org/wiki/Asteroid
Schaum's Outlines of Astronomy
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| Asteroid Ida with ts satelitte(Dactyl) |
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| Ceres |
In addition to the asteroids in the belt, some asteroids share Jupiter’s orbit. Asteroids in this special group are called Trojan asteroids, and they orbit about 608 ahead or behind Jupiter. Their orbits are stabilized by the combined gravity of Jupiter and the Sun. Over 150 of these are known; the largest is about 300km in size.
Astronomers estimate that the asteroid was created the same time as our solar system. They are byproduct. As theory said that planets formed by the joining of the asteroids. Asteroids on the Asteroid belt is the rest of solar system material when was created. They have stable gravitional in there.
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| An asteroid approching erth |
Earth.
Asteroids do not emit visible light, they only reflect it. Astronomers determinethe compositions of asteroids by comparing the spectrum of the light reflected by the asteroid and the spectrum of the Sun. Absorption lines that are present in the asteroid’s spectrum, but not in the solar spectrum, must be due to elements or minerals in the asteroid. Asteroids are classified in three major groups: carbonaceous (C), silicate (S), and metallic (M). Most asteroids are C-type asteroids, with very low albedo and no strong absorption lines. The rest are mainly S type, with an absorption feature due to a silicate mineral, olivine.
The amount of light reflected from an asteroid towards the Earth changes as the asteroid tumbles through space. We can use this information to determine how quickly the asteroids rotate. About 500 asteroids have been studied well enough to determine their rotation periods, which are generally between 3 and 30 hours.
Smaller asteroids have irregular shapes. The shape of small asteroids can be determined from analysis of the amount of radiation received over time (light curve).
Source : http://en.wikipedia.org/wiki/Asteroid
Schaum's Outlines of Astronomy
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