It may seem circular when viewed from space, but our planet is actually a bumpy spheroid
By" Charles Q. Choi"
As countless photographs can confirm from space earth around-the "Blue Marble" as astronauts affectionately called it. Appearances, however, can be misleading. Planet Earth is not, in fact, perfectly round.
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This is not to say that the earth is flat. Well before Columbus sailed the ocean blue, Aristotle and other ancient Greek scholars proposed that the earth was round. This was based on a number of observations, such as the fact that the departing ships not only seemed smaller as they sailed away, but also seemed to sink into the horizon, as one would expect when sailing on a ball says geographer Bill Carstensen Virginia Tech Blacksburg.
Isaac Newton first proposed that the earth is not perfectly round. Instead, he suggested that the sphere is an oblate spheroid-one that is squashed at the poles and swollen at the equator. He was correct and, as a result of this projection, the distance from the center of the Earth at sea level is about 21 kilometers (13 miles) is greater at the equator than at the poles.
In place of the earth like a top made of steel, says geologist Vic Baker of the University of Arizona in Tucson has "a bit of plasticity that allows the shape very slightly deformed., The effect would be similar to turning a Putty little weird, but plasticity Earth is much, much less than that of the silicone plastic clay known as children. "
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Our world, however, is not even a perfect oblate spheroid, because mass unevenly distributed across the planet. The greater the concentration of the mass, the stronger the gravity, "creating bumps all over the world," says geologist Joe Meert at the University of Florida in Gainesville.
Shape of the earth is changing over time due to a menagerie of other dynamic factors. Mass shifts around inside the planet, changing the gravity anomalies. Mountains and valleys appear and disappear as a result of plate tectonics. Occasional meteor crater surface. And the attraction of the moon and the sun not only cause ocean and atmospheric tides, but also earth tides.
In addition, the changing weight of the oceans and the atmosphere of the Earth's crust deformations cause "in the order of a centimeter or so," says geophysicist Richard Gross of the Jet Propulsion Laboratory in Pasadena, Calif. "There is postglacial rebound, with the crust and mantle that were printed by the massive ice sheets during the last ice age now rebounding upward in the order of one centimeter per year was on the surface. "
Moreover, to even out uneven distribution of the mass of the earth and stabilize the spin "the entire surface of the earth will turn and try to divide along the equator, a process called true polar wander the masses," said Meert.
In order to keep the shape of the earth to keep track of, scientists now places thousands of Global Positioning System receivers on the ground that can detect changes in a height of only a few millimeters, said Gross. Another method, called satellite laser ranging, fires visible wavelength lasers from a few dozen ground stations to satellites. Any detected in their orbits changes correspond to the gravitational anomalies, and hence mass distribution inside the planet. Yet another technique, a very long baseline interferometry is radio telescopes-spot listening extragalactic radio waves changes in the positions of the ground stations to detect. It might not be a lot of technology to understand that the earth is not perfectly round, but it takes a bit of effort and equipment to determine. His true form
By" Charles Q. Choi"
As countless photographs can confirm from space earth around-the "Blue Marble" as astronauts affectionately called it. Appearances, however, can be misleading. Planet Earth is not, in fact, perfectly round.
This is not to say that the earth is flat. Well before Columbus sailed the ocean blue, Aristotle and other ancient Greek scholars proposed that the earth was round. This was based on a number of observations, such as the fact that the departing ships not only seemed smaller as they sailed away, but also seemed to sink into the horizon, as one would expect when sailing on a ball says geographer Bill Carstensen Virginia Tech Blacksburg.Isaac Newton first proposed that the earth is not perfectly round. Instead, he suggested that the sphere is an oblate spheroid-one that is squashed at the poles and swollen at the equator. He was correct and, as a result of this projection, the distance from the center of the Earth at sea level is about 21 kilometers (13 miles) is greater at the equator than at the poles.
In place of the earth like a top made of steel, says geologist Vic Baker of the University of Arizona in Tucson has "a bit of plasticity that allows the shape very slightly deformed., The effect would be similar to turning a Putty little weird, but plasticity Earth is much, much less than that of the silicone plastic clay known as children. "
Also see : Whale Waste Is Extremely Valuable
Our world, however, is not even a perfect oblate spheroid, because mass unevenly distributed across the planet. The greater the concentration of the mass, the stronger the gravity, "creating bumps all over the world," says geologist Joe Meert at the University of Florida in Gainesville.
Shape of the earth is changing over time due to a menagerie of other dynamic factors. Mass shifts around inside the planet, changing the gravity anomalies. Mountains and valleys appear and disappear as a result of plate tectonics. Occasional meteor crater surface. And the attraction of the moon and the sun not only cause ocean and atmospheric tides, but also earth tides.
In addition, the changing weight of the oceans and the atmosphere of the Earth's crust deformations cause "in the order of a centimeter or so," says geophysicist Richard Gross of the Jet Propulsion Laboratory in Pasadena, Calif. "There is postglacial rebound, with the crust and mantle that were printed by the massive ice sheets during the last ice age now rebounding upward in the order of one centimeter per year was on the surface. "
Moreover, to even out uneven distribution of the mass of the earth and stabilize the spin "the entire surface of the earth will turn and try to divide along the equator, a process called true polar wander the masses," said Meert.
In order to keep the shape of the earth to keep track of, scientists now places thousands of Global Positioning System receivers on the ground that can detect changes in a height of only a few millimeters, said Gross. Another method, called satellite laser ranging, fires visible wavelength lasers from a few dozen ground stations to satellites. Any detected in their orbits changes correspond to the gravitational anomalies, and hence mass distribution inside the planet. Yet another technique, a very long baseline interferometry is radio telescopes-spot listening extragalactic radio waves changes in the positions of the ground stations to detect. It might not be a lot of technology to understand that the earth is not perfectly round, but it takes a bit of effort and equipment to determine. His true form
