The Kuiper belt is the circumstellar disc located at the edge of solar system. It is extended from the orbit of Neptune (at 30 AU) to approximately 50 AU from the Sun. It is a kind of asteroid belt but it is far larger 200 times as massive. It mainly consist of massive bodies and remnant when the solar system is formed. While most of the asteroid belt consist of solid rock and metal, Kuiper belt consist largely of
frozen volatiles such as methane, ammonia and water. The three dwarf planets Pluto, Makemake and Haumea are present in Kuiper belt. It is expected that some of the solar system moons like Neptune's Triton and Saturn's Phoebe, may have originated in the region.
Oort cloud
The Kuiper Belt shouldn't be confused with the Oort Cloud, which is an even more distant, spherical region of icy, comet-like bodies that surrounds the solar system, including the Kuiper Belt. But both the Oort Cloud and the Kuiper Belt are thought to be sources of comets.
The first spacecraft to enter the Kuiper Belt region was NASA's Pioneer 10 spacecraft, when it crossed into the space beyond Neptune's orbit in 1983. But that spacecraft didn't visit any of the icy worlds in the region—none other than Pluto had been discovered yet. (Voyager 2 visited Neptune's moon Triton in 1989, and Cassini visited Saturn's moon Phoebe in 2004—both could be worlds originally from the Kuiper Belt that have escaped.)
The first spacecraft to actually visit an object in the Kuiper Belt was NASA's New Horizons, which flew by Pluto and its moons in July 2015. New Horizons is slated to fly past another KBO—2014 MU69 (nicknamed "Ultima Thule" by the mission) on New Year's Eve 2018.
The Kuiper Belt is a source of comets, as it very slowly erodes itself away. Pieces produced by colliding KBOs can be pushed by Neptune's gravity into orbits that send them sunward, where Jupiter's gravity further corrals them into short loops lasting 20 years or less. These are called short-period Jupiter-family comets. Given their frequent trips into the inner solar system, most tend to exhaust their volatile ices fairly quickly and eventually become dormant, or dead, comets with little or no detectable activity.Researchers have found that some near-Earth asteroids are actually burned-out comets, and most of them would have started out in the Kuiper Belt. (The other source of comets is the Oort Cloud, where most long-period comets on highly tilted orbits originate.)
A fairly large number of KBOs either have moons—that is, significantly smaller bodies that orbit them—or are binary objects. Binaries are pairs of objects that are relatively similar in size or mass that orbit around a point (a shared center of mass) that lies between them. Some binaries actually touch, creating a sort of peanut shape, creating what's known as a contact binary. Pluto, Eris, Haumea and Quaoar are all Kuiper Belt objects that have moons.
frozen volatiles such as methane, ammonia and water. The three dwarf planets Pluto, Makemake and Haumea are present in Kuiper belt. It is expected that some of the solar system moons like Neptune's Triton and Saturn's Phoebe, may have originated in the region.
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| Artist's impression of the view from a KBO. The four giant planets appear as bright dots, but inner planets are too close to the Sun to be seen. Credit: NASA, ESA, and G. Bacon (STScI) |
Oort cloud
The Kuiper Belt shouldn't be confused with the Oort Cloud, which is an even more distant, spherical region of icy, comet-like bodies that surrounds the solar system, including the Kuiper Belt. But both the Oort Cloud and the Kuiper Belt are thought to be sources of comets.
The first spacecraft to enter the Kuiper Belt region was NASA's Pioneer 10 spacecraft, when it crossed into the space beyond Neptune's orbit in 1983. But that spacecraft didn't visit any of the icy worlds in the region—none other than Pluto had been discovered yet. (Voyager 2 visited Neptune's moon Triton in 1989, and Cassini visited Saturn's moon Phoebe in 2004—both could be worlds originally from the Kuiper Belt that have escaped.)
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| These four panels show the relative scale of (clockwise from top left): The inner solar system, outer solar system, orbit of Sedna in the scattered disk, and the Oort Cloud. Credit: NASA/Caltech |
The first spacecraft to actually visit an object in the Kuiper Belt was NASA's New Horizons, which flew by Pluto and its moons in July 2015. New Horizons is slated to fly past another KBO—2014 MU69 (nicknamed "Ultima Thule" by the mission) on New Year's Eve 2018.
The Kuiper Belt is a source of comets, as it very slowly erodes itself away. Pieces produced by colliding KBOs can be pushed by Neptune's gravity into orbits that send them sunward, where Jupiter's gravity further corrals them into short loops lasting 20 years or less. These are called short-period Jupiter-family comets. Given their frequent trips into the inner solar system, most tend to exhaust their volatile ices fairly quickly and eventually become dormant, or dead, comets with little or no detectable activity.Researchers have found that some near-Earth asteroids are actually burned-out comets, and most of them would have started out in the Kuiper Belt. (The other source of comets is the Oort Cloud, where most long-period comets on highly tilted orbits originate.)
A fairly large number of KBOs either have moons—that is, significantly smaller bodies that orbit them—or are binary objects. Binaries are pairs of objects that are relatively similar in size or mass that orbit around a point (a shared center of mass) that lies between them. Some binaries actually touch, creating a sort of peanut shape, creating what's known as a contact binary. Pluto, Eris, Haumea and Quaoar are all Kuiper Belt objects that have moons.
So far, more than 2,000 Kuiper Belt objects, or KBOs, have been cataloged by observers, but they represent only a tiny fraction of the total number of objects scientists think are out there. Astronomers estimate there are hundreds of thousands of objects in the Kuiper Belt region that are at least 60 miles- (100 kilometers-) wide or larger.
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