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====Sir Issac Newton's theory of gravitation had revolutionary impact and was accepted without many questions...until the beginning of the 20th century, when the famous German-born scientist Albert Einstein came around the corner. With the introduction of the Special Theory of Relativity, Einstein showed that Newton's Three Law of Motion were correct except when velocities approached the speed of light. But, that's not all...Einstein's General Theory of Relativity, proposed only ten years after, claimed that Sir Newton's Law of Gravitation worked, when excluding the presence of strong gravitational fields (such as a black hole).====

====Following its introduction, Albert Einstein's Theory of Relativity has been analyzed in different ways and numerous times verified by observations from modern instruments such as artificial satellites. Many of these observations supported the theory's claims. Today, Einstein's theory of relativity is mostly accepted by the scientific world.====

SOME BACKGROUND INFORMATION... ====Einstein's theory of relativity has two precise parts: special relativity and general relativity. The Special Theory of Relativity claims that the speed of light is the same for all observers, regardless of their relative speeds and that the laws of physics observed by an observer traveling with a relative particle must be the same as those observed by an observer who remains stationary. The General Theory of Relativity proposes that gravity and motion can affect the intervals of time and of space. The equivalence principle, the principle idea of general relativity, refers to the idea that gravity in one direction is completely equivalent to an acceleration the opposite direction. For example, a car accelerating forwards feels the same as gravity pushing you backwards against your seat (Alan).====

SUPPORTING EVIDENCE...





Gravitational Red-Shift
====X-Ray astronomy is continuing to verify key aspects of Albert Einstein's General Theory of Relativity. Using the Japanese-built ASCA X-ray satellite in 1995, astronomers first observed an indication of gravitational red-shift (the idea of gravity pulling a photo, a light particle, as it tries to escape) around a black hole. The ASCA X-ray satellite indicated a broad iron line that revealed the presence of gravity sucking energy from the emitted light. This observation supports Einstein's claim that black holes create a gravitational force and that a photo particle must climb its way out of the black hole. Today, Einstein's prediction is further verified to a greater precision by the Chandra X-ray Observatory and the XMM-Newton satellite ("X-ray Astronomy").====

===**Frame-Dragging** ===

====Over the years, scientists have observed a more exotic prediction of the General Theory of Relativity: the frame-dragging phenomenon. Einstein's equations predict that when an object with strong gravity spins, it takes space-time along with its spin. Scientists have used instruments such as the Rossi X-ray Timing Explorer (holds unprecedented time resolution and moderate spectral resolution to explore the variability of X-ray sources) to observe the orbit of matter around a black hole. It was concluded that the orbit was hastened by the shifting of space ("X-ray Astronomy").====

====Recently, two scientists by the name of Ignazio Ciufolini and Erricos Pavlis measured the phenonmenon by studying the movements of two satellites in Earth’s orbit over a time span of 11 years. Ciufolini and Pavlis analyzed laser range-finding signals reflected by Lageos and Lageos 2 satellites. The researchers analyzed the signals for evidence that the satellites' orbits were affected by frame-dragging. The two scientists claim that their result is 99% of the value predicted by Einstein's theory, plus or minus 5%. They also say that this result has an uncertainty of about 10% ("BBC News").====

The Environment of Neutron Stars & Black Holes
====The General Theory of Relativity also has predictions for the environments of neutron stars and black holes. The theory proposes that matter cannot orbit too closely; it must have an innermost stable orbit. This idea opposes the Newtonian law, which claims that matter can orbit at any radii. The Rossi Explorer has verified this prediction by determining that a specific black hole in the universe is spinning at an extremely light and stable orbit. Furthermore, the idea of an innermost stable orbit and the effects of General Relativity have been used in conjunction to explain quasi-periodic oscillations, or X-ray flickering ("X-ray Astronomy").====



 IN CONCLUSION... ====Even though the Theory of General Relativity has not yet been tested completely by scientists, many observations have been made to support and verify Einstein's predictions. Such observations include indications of gravitational red-shifting and the frame-dragging effect and predictions for the environments of neutron stars and black holes. However, if an effort was made to completely test the theory, it may result in a better version of the theory of gravity, just like how Einstein improved Newton's theory of gravitation.====

"BBC NEWS | Science/Nature | Einstein's warp effect measured." __BBC NEWS | News Front Page__. 21 Oct. 2004. 8 Feb. 2009 .
====Numerous experiments have been conducted to test the frame-dragging phenomenon as proposed by Einstein's General Theory of Relativity. This site includes an example of the result and findings of two scientists. This article is published by the Science/Nature section of the BBC News. The content is very accurate and unbiased.====

Lightman, Alan. "NOVA | Einstein's Big Idea | Relativity (Lightman Essay) | PBS." __PBS__. 5 Feb. 2009 .
==== This site offers detailed information on the difference between general and special relativity. This site also detailed how the theory of relativity can be applied to numerous ideas, such as the big bang theory. Relativity and the Cosmos is an article written by Alan Lightman, the Adjunct Professor of Humanities at MIT. The information offered by this site is very valid considering the credentials of this author.====

Theory: Special Relativity (SLAC VVC)." __SLAC Public Website Server__. 31 Oct. 2008. 5 Feb. 2009 .
==== This site details the theoretical basis of the theory of relativity. Furthermore, it provides a in depth analysis of Einstein's famous equation, E=mc^2. Since this site is operated by the National Accelerator Laboratory supported by the U.S. Department of Energy, the information provided is very valid. All claimed facts are unbiased.====

"X-ray Astronomy Puts Einstein to the Test." __Imagine The Universe! Home Page__. 20 Aug. 2008. 5 Feb. 2009 .
====Current technology has been used to test the validity of the theory. This article explains how black hole and neutron stars support Einstein's theory of relativity. Operated by NASA, a government supported agency, this site contains no biased information. Considering the credentials of the organization, the content should be very valid.====