"a little science" Einstein continues to surprise us ... ... The distortion of space-time predicted by the scientist through her theory of general relativity ...
Thursday, May 19, 2011
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Einstein was right
Recreation Gravity Probe B in space-time distorted by the Earth in depth.
The space probe
NASA Gravity Probe B has just confirmed the distortions of space-time predicted by the Theory of General Relativity of Einstein. Culmination of a long company that has taken five decades of work and more than 750 million dollars. Meanwhile, this same phenomenon has been shown by other experiments, which has caused a debate in the scientific community about the need and desirability of Gravity Probe B.
The space-time as molten chocolate
Albert Einstein.
The General Theory of Relativity formulated by Albert Einstein in 1916 is still the best existing description of gravity, possibly more physical strength in determining the structure and evolution of the Universe.
Under German physicist, a massive body curves space-time in their environment, which causes light rays in the area leave the straight path to follow curved paths, is what is known as the 'geodetic effect' .
Another consequence of Einstein's theory, Austrian physicists predicted by Lense and Thirring in 1918, is that if that body mass is rotating (as the Earth), the lines of space-time is even more distorted, twisting to accompany the shift. This is what is known as' drag the frame of reference. "
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drag representation of space-time. Enlarge photo
One of the gyroscopes removed Probe B, after multiple studies and adventures, was released in 2004.
The satellite was put into polar orbit about 650 km altitude, and the axis of rotation of the gyroscopes (spacecraft that are in a situation equivalent to zero) was carefully oriented in the direction of the star IM Pegasi. If spacetime were not curved, the axis of rotation of the quartz beads should not vary over time. But what has been observed is that due to the geodetic effect predicted by Einstein, the axis of rotation varies (precesses) in 6601.8 milliseconds of arc per year (with a margin of error of 0.3 percent).
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measures Gravity Probe B for the great physicist.
However, this is not the first time that Einstein's theory has undergone this type of test is, other experiments carried out previously, these effects have been measured even more accurately.
For example, there were other similar tests in the early 1970's through the precise measurement of motion of the moon, this was achieved a laser reflecting mirrors that were installed on the lunar surface by the Apollo missions. Also the study of binary pulsars and laser tracking of LAGEOS satellites allowed us to validate Einstein's theory itself. Finally, the extent of the delays experienced by a radio signal emitted by the Cassini spacecraft managed to measure the geodetic effect to a precision of 0.002 percent.
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Recreation Gravity Probe B extraordinary private capital, including the royal family of Saudi Arabia, which allowed refining the data analysis. Time were made very detailed models of instrumental effects that altered the rotation of the spheres in undesirable ways, to achieve acceptable accuracy in identifying relativistic effects.
Francis Everitt, the physicist at Stanford University who has piloted the mission during these five decades, can finally breathe easy after reaching its target in a way that has been described as heroic. Their data fit well with both theory and with previous measurements.
However, these new findings may technological implications were greater than the purely scientific. The developed technology could be used to optimize the manufacture of watches on board spacecraft. It is hoped that data from Gravity Probe B will be useful to improve the accuracy of global positioning systems with satellite constellations. Also interesting
Spheres of Gravity Probe B entered the Guinness Book of Records for being the most perfect man-made. The irregularities on their surfaces do not exceed a thickness of 40 atoms. If one of these areas had the size of Earth, its valleys and mountains do not exceed, respectively, the 2 m depth and height. The spheres rotate at about 10,000 revolutions per minute.
Magnetic shielding of the gyros was achieved by installing it in a Dewar flask lead of 1.25 inches thick cooled with liquid helium, about 271 degrees Celsius. At such low temperatures, lead becomes superconducting and serves as magnetic screen efficiently, keeping the magnetic field in the fields below 3 microgauss. Turning areas, the bathroom of niobium (also superconductor) creates a small magnetic field aligned with the axis of rotation (through the so-called 'London effect'). Electronic sensors (type SQUID) detected changes in the field magnetic recording and the precession of the axis of rotation.
Although near zero gravity, the Gravity Probe B could not avoid being subject to occasional acceleration. Such accelerations were compensated immediately by pulses generated in the satellite's propulsion system. In this way the severity of the gyroscopes that were subject never exceeded one ten-billionth of Earth's gravity. Rafael Bachiller
is director of the National Astronomical Observatory
(National Geographic Institute)
.
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