Author : David Craig
Nasa completed the experimental phase of an attempt to test Albert Einstein's crowning achievement, his General Theory of Relativity, in early October 2005. Fifty weeks of data collecting will be followed by a year long data analysis phase, and a six month report preparation period. The results will be announced in 2007.Einstein's Special Theory of Relativity reformulated Isaac Newton's theory of classical mechanics that was based on the existence of the three physical dimensions we can detect with our senses incorporated with time as a separate non-physical entity. Einstein added time as an equal dimension to form the mathematically consistent and experimentally proven concept of spacetime. In 1916 Albert Einstein proposed his crowning achievement, the heretofore experimentally unverified General Theory of Relativity.In his General Theory, Einstein proposed that a mass actually causes an almost imperceptible perturbation in the fabric of spaetime. If proven, this discredits Newton's interpretation of gravity as a force. Gravity would then be an interwoven component of spacetime rather than a force. Under ideal conditions, according to Newton, a perfectly gyrating body whose axis is aimed at a fixed point and under no net external force, would never have its axis of rotation disturbed. That is, what physicists refer to as its spin would remain constant.Einstein's theory suggests that the presence of a large nearby mass would have two effects on the gyroscope. One, the geodetic effect would be a simple change in the spin of the gyroscope. A second effect, known as frame dragging, would occur if the gyroscope were moving relative to the mass in non-linear motion, such as placed in an orbit around the larger mass. This measurement would cause a change in the spin component perpendicular to that of the geodetic effect. Its movement actually would drag spacetime around with it.For the earth with a gyroscope in an orbit of 400 meters in altitude, values of only .00018 degrees for the geodetic effect and .000011 degrees for the frame-dragging effect are predicted. The challenge becomes to detect changes this small with the development of adequately sensitive sensors, and to reduce background interference to a level that would not drown out the signals being received.The simple experiment of Gravity Probe–B, or GP-B, consisted of placing four almost perfectly round gyroscope rotors, (one million times more round than any previously existing), on a satellite orbiting the earth. A telescope on the satellite fixated on the position of the star IM Pegasi. The background disturbance which had created so much uncertainty in previous experiments was eliminated by surrounding the gyroscopes in super fluid conditions. Liquid helium in Dewar flasks was used to obtain this.The results of this experiment will shed light on the nature of the universe beyond our solar system where bodies with masses that dwarf our sun's abound, uncovering keys into mysteries of the nature of the universe utilizing Einstein's greatest achievement.1) Nasa News Release 05-160 http://www.nasa.gov/centers/marshall/news/news/releases/2005/05-160.html 10-3-05
2) Putting relativity to the test - http://www.stanford.edu/ - Stanford 10/9/05
3) Nasa Facts – Marshall Space Center – February 2005David Craig
M.S. Physics - University of MinnesotaB.S. Computer Science - University of OregonCome visit me at my general astronomy and Nasa site for more interesting articles
Keyword : nasa, general theory of relativity, einstein, gp-b, gravity probe-b, general relativity test,
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