Although lacking the glamor of comets and having long lines and steam bright particles carried by the solar wind, asteroids are the group of large solid elements most abundant in the solar system and almost certainly of any planetary system orbiting around a star. We call every rocky body asteroid, metallic or carbonaceous smaller than a planet and more than a meteoroid that orbits around the sun draws without going beyond Neptune. Observed from Earth, asteroids have the appearance of a star, hence its name which means "star figure", name given by John Herschel shortly after the first discovery. Currently, the asteroids are called planetoid or minor planets, names that are more suited to what they really are, and includes in the same category as comets and those bodies with orbits beyond Neptune drawn, called trans-Neptunian objects. Most asteroids in our present system semistable orbits between Mars and Jupiter, forming the asteroid belt, but some are diverted into orbits that cross the major planets and risk of hitting as they meteorites, as could be documented during the collision of Comet Shoemaker - Levy 9 with Jupiter.
The way in which these bodies are classified is very uneven and often controversial, but generally the methodology has been changing gradually over several centuries. Until recently, the most widespread method included five categories: Asteroid Belt, near-Earth asteroid, or NEA, coorbitantes Earth Asteroids, Asteroids Asteroids Centaurs and Trojans, while today it is generally preferred spectral system consisting serve its optical spectrum, which is corresponding to the composition of its surface and takes into account its albedo, ie the amount of sunlight they reflect. To date, qualifying eight categories recognized by this procedure, to be called Type C, D, E, F, R, S, T and V.
The dimensions of these "rocks orbitals are the most varied, the larger the seriousness of which confers a quasi-spherical appearance, were classified as recently as a dwarf planet Ceres is the case with 952 kilometers in diameter, while smaller have only ten meters in diameter setting, since the bodies of less size are already classified as meteoroids. Some estimates indicate that at least two million asteroids with diameters media larger than a kilometer one hundred and fifty million or more that are over a hundred meters and is estimated at billions of them measuring more than ten meters.
For centuries, the asteroid passed almost unnoticed, its subtle brightness seen from Earth just allowed the observation of those solids that are close enough and when they were discovered and described often mingled with the faint planets. The invention of the telescope and its exponential technological development brought about a revolution in the field, it allowed massive look and catalog asteroids of sizes and compositions of the most varied. The space was subsequently provided valuable tools and techniques which allowed a much more detailed and precise, they can be recognized with physical and chemical characteristics of comets and asteroids. But it was another branch of science and technology associated to that space age look that has allowed these "rocks from space" in a way unimaginable even a few decades ago, as the use of unmanned space probes has allowed not only to observe and analyze asteroids but also to visit, collect samples of their surfaces and even perch on them gently as if it were landing.
Indeed, space probes have opened a world of possibilities to learn more about asteroids and comets in the solar system; Each machine is designed and built to a specific scientific mission but sometimes after being held for reuse as its objective experience, taking in most of your technology.
Near Earth Asteroid Rendezvous, NEAR Shoemaker known as the concept is kind of what should be an asteroid spacecraft, this device, launched by NASA on February 17, 1996 with mass greater than eight hundred kilograms was part of the Program Discovery and was nothing less than serious study of a near-Earth asteroid, namely the 433 - Eros, the second largest near-Earth object (not counting the Moon), with a size of 13 km in height and 33 width 13 length. After solving the many technical problems in space, the probe is close enough to its target on December 23 of that year, at a speed of 965 meters per second and kept at a distance of 3827 kilometers for a path approach and finally reach back and go into orbit on 14 February 2000. Obtained its initial goal, the team responsible for the functioning and operation of NEAR Shoemaker decided to improvise the first landing of the story about an asteroid, which was achieved on 21 February 2001 after two attempts. Photographs and other data obtained from this body discovered by Gustav Witt on August 13 of 1,898 are among the best captured by an asteroid. Despite the setbacks, the mission was a great success.
Another similar machine is called the Deep Space One, which was nothing more than a technology demonstrator to prove a number of novel technologies relating to space exploration. The probe, U.S. Billing, was launched on October 24, 1998, flew by the asteroid 9969 - Braille in July 1999 and comet Borrelly in 2001, adding scientific value to the mission could be extended several times until its completion in 2,001. Deep Space One was the first mission of NASA's New Millennium, but given its experimental nature not particularly good data obtained from the bodies flying.
missions already made mention of this caliber, I think requires special mention of the Hayabusa probe Japan Aerospace Exploration Agency whose purpose was to collect samples of an asteroid near Earth orbit and return them to Earth for analysis , the object chosen was 25143 - Itokawa, barely three hundred by hundred-meter wingspan. This mission seems to me personally very worthwhile, not only because of the complexity of their task, they had never tried to collect samples for return to Earth with them, but also had to overcome countless technical barriers, including its dying return to their damaged engines after a rough sampling not allowed out for sure if it had been successful until the opening of the sampling container in the laboratory. I commend the efforts of the Japan team who worked tirelessly to keep the ailing running wave face of adversity knowing that their work could well be in vain if there was any sign ignored inside the PLC. Too bad the elements obtained were tiny, but at least the effort was rewarded.
For its part, also the Galileo spacecraft, built specifically to investigate the system of Jupiter and its satellites, was able to visit an asteroid by the way, providing valuable scientific material of the objects studied while I had the chance to test their scientific instruments before boarding their primary mission. Thanks to this wonderful probe now know much better than 951 - and 243 Gaspra - Ida with its small satellite.
In the future, it appears to be more and better, as the space agencies of the United States, Japan and Europe have some of the most exciting projects on the study of asteroids. A good example of this situation has its own name is called Dawn Mission and 1237 kg were launched in September 2007 to hunt for 4 - Vesta and Ceres. Dawn is expected to focus on his first goal next year and reach Ceres in 2015, I have high hopes to learn about this fascinating dwarf planet, which incidentally is the first objective of this group to be visited.
The way in which these bodies are classified is very uneven and often controversial, but generally the methodology has been changing gradually over several centuries. Until recently, the most widespread method included five categories: Asteroid Belt, near-Earth asteroid, or NEA, coorbitantes Earth Asteroids, Asteroids Asteroids Centaurs and Trojans, while today it is generally preferred spectral system consisting serve its optical spectrum, which is corresponding to the composition of its surface and takes into account its albedo, ie the amount of sunlight they reflect. To date, qualifying eight categories recognized by this procedure, to be called Type C, D, E, F, R, S, T and V.
The dimensions of these "rocks orbitals are the most varied, the larger the seriousness of which confers a quasi-spherical appearance, were classified as recently as a dwarf planet Ceres is the case with 952 kilometers in diameter, while smaller have only ten meters in diameter setting, since the bodies of less size are already classified as meteoroids. Some estimates indicate that at least two million asteroids with diameters media larger than a kilometer one hundred and fifty million or more that are over a hundred meters and is estimated at billions of them measuring more than ten meters.
For centuries, the asteroid passed almost unnoticed, its subtle brightness seen from Earth just allowed the observation of those solids that are close enough and when they were discovered and described often mingled with the faint planets. The invention of the telescope and its exponential technological development brought about a revolution in the field, it allowed massive look and catalog asteroids of sizes and compositions of the most varied. The space was subsequently provided valuable tools and techniques which allowed a much more detailed and precise, they can be recognized with physical and chemical characteristics of comets and asteroids. But it was another branch of science and technology associated to that space age look that has allowed these "rocks from space" in a way unimaginable even a few decades ago, as the use of unmanned space probes has allowed not only to observe and analyze asteroids but also to visit, collect samples of their surfaces and even perch on them gently as if it were landing.
Indeed, space probes have opened a world of possibilities to learn more about asteroids and comets in the solar system; Each machine is designed and built to a specific scientific mission but sometimes after being held for reuse as its objective experience, taking in most of your technology.
Near Earth Asteroid Rendezvous, NEAR Shoemaker known as the concept is kind of what should be an asteroid spacecraft, this device, launched by NASA on February 17, 1996 with mass greater than eight hundred kilograms was part of the Program Discovery and was nothing less than serious study of a near-Earth asteroid, namely the 433 - Eros, the second largest near-Earth object (not counting the Moon), with a size of 13 km in height and 33 width 13 length. After solving the many technical problems in space, the probe is close enough to its target on December 23 of that year, at a speed of 965 meters per second and kept at a distance of 3827 kilometers for a path approach and finally reach back and go into orbit on 14 February 2000. Obtained its initial goal, the team responsible for the functioning and operation of NEAR Shoemaker decided to improvise the first landing of the story about an asteroid, which was achieved on 21 February 2001 after two attempts. Photographs and other data obtained from this body discovered by Gustav Witt on August 13 of 1,898 are among the best captured by an asteroid. Despite the setbacks, the mission was a great success.
Another similar machine is called the Deep Space One, which was nothing more than a technology demonstrator to prove a number of novel technologies relating to space exploration. The probe, U.S. Billing, was launched on October 24, 1998, flew by the asteroid 9969 - Braille in July 1999 and comet Borrelly in 2001, adding scientific value to the mission could be extended several times until its completion in 2,001. Deep Space One was the first mission of NASA's New Millennium, but given its experimental nature not particularly good data obtained from the bodies flying.
missions already made mention of this caliber, I think requires special mention of the Hayabusa probe Japan Aerospace Exploration Agency whose purpose was to collect samples of an asteroid near Earth orbit and return them to Earth for analysis , the object chosen was 25143 - Itokawa, barely three hundred by hundred-meter wingspan. This mission seems to me personally very worthwhile, not only because of the complexity of their task, they had never tried to collect samples for return to Earth with them, but also had to overcome countless technical barriers, including its dying return to their damaged engines after a rough sampling not allowed out for sure if it had been successful until the opening of the sampling container in the laboratory. I commend the efforts of the Japan team who worked tirelessly to keep the ailing running wave face of adversity knowing that their work could well be in vain if there was any sign ignored inside the PLC. Too bad the elements obtained were tiny, but at least the effort was rewarded.
For its part, also the Galileo spacecraft, built specifically to investigate the system of Jupiter and its satellites, was able to visit an asteroid by the way, providing valuable scientific material of the objects studied while I had the chance to test their scientific instruments before boarding their primary mission. Thanks to this wonderful probe now know much better than 951 - and 243 Gaspra - Ida with its small satellite.
In the future, it appears to be more and better, as the space agencies of the United States, Japan and Europe have some of the most exciting projects on the study of asteroids. A good example of this situation has its own name is called Dawn Mission and 1237 kg were launched in September 2007 to hunt for 4 - Vesta and Ceres. Dawn is expected to focus on his first goal next year and reach Ceres in 2015, I have high hopes to learn about this fascinating dwarf planet, which incidentally is the first objective of this group to be visited.
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