Theory of relativity

The Theory of Relativity is a geometrical theory of gravitation, it postulates that the speed of light and laws of physics are constant for all (inertial) observers, regardless of their velocities relative to each other.

The theory of relativity was first proposed based on mathematical theory developed by Henri Poincaré and Hendrik Lorentz. This theory differs from Isaac Newton's theory of gravitation by disposing with the idea of a universal, mutually agreeable scale of time (i.e. a universal clock that all times can refer to) and space (i.e. a universal sheet of "graph paper", which location refers to).

The famous equation attributed to Einstein, E=mc², describes the relationship between energy and the rest mass of a body.

In general terms, relativity predicts that space-time can be curved by massive bodies, so that (for example) near a black hole the sum of the angles in a triangle is not exactly 180 degrees, time passes more rapidly away from a black hole than near it (for a distant observer) and other apparent violations of geometry and common sense.

Relativity is important for massive or fast-moving bodies: at low mass and low speed, it can be accurately approximated by classical mechanics (such as Isaac Newton's laws of motion). At the two extremes, modeling the behavior of electrons requires that relativistic effects be taken into account (the chemically significant phenomenon of electron spin arises from relativity), and the course light passing through a region containing many massive bodies such as galaxies will be distorted (classical mechanics, in which light travels with infinite speed in straight lines, does not predict this). These are both experimentally confirmed (electron spin was known before relativity arose, and telescopic observations confirm that galactic clusters distort the paths of the light passing through them).

General relativity successfully explains the seemingly anomalous precession of Mercury's perihelion. While other explanations based in Newtonian gravity had been proposed, none were consistent with observation.

British Historian Paul Johnson declares the turning point in 20th century to have been when fellow Briton Sir Arthur Eddington, an esteemed English astronomer, ventured out on a boat off Africa in 1919 with a local Army unit to observe the bending of starlight around the sun during a total eclipse. Upon his return to England declared that his observations proven the theory of relativity. In fact recent analysis of Eddington's work revealed that he was biased in selecting his data, and that overall his data were inconclusive about the theory of relativity. The prediction was later confirmed by more rigorous experiments, such as those performed by the Hubble Space Telescope^{[Citation Needed]}. Lorentz has this to say on the discrepancies between the empirical eclipse data and Einstein's predictions.

It indeed seems that the discrepancies may be ascribed to faults in observations, which supposition is supported by the fact that the observations at Prince's Island, which, it is true, did not turn out quite as well as those mentioned above, gave the result, of 1.64, somewhat lower than Einstein's figure. [1]

The prediction that light is bent by gravity is predicted both by Newtonian physics and relativity, but relativity predicts a larger deflection.

Evidence for Relativity

No particle accelerator built since the 1950s would work unless the mass increase predicted by special relativity not only occurred, but occurred to the precise degree predicted by the theory.^{[Citation Needed]} In 1972, scientists flew extremely accurate clocks around the world in both directions on commercial airlines, and were directly able to observe the relativistic "twin paradox" the eastbound clock gained 273 ns and the westbound clock lost 59 ns, matching the predictions of general relativity to within experimental accuracy.

Evidence Against Relativity

Evidence against the theory of relativity includes the following:

it is incompatible with quantum mechanics, which has been more thoroughly verified

space has no overall curvature to it

neither "gravity waves" nor gravitons have ever been discovered despite diligent searches

some experiments have suggested variations in the speed of light

There is little doubt that a greater force is required to accelerate masses as their velocity approaches the speed of light. But there are other theories other than relativity that can account for that basic phenomenon.

Pending Research

Today some physicists are working on a quantum theory of gravity (the "theory of everything"), such as string theory and loop quantum gravity. Critics increasingly point out that string theory and loop quantum gravity are largely untestable and unfalsifiable, and thus potentially unscientific under the principles of science advanced by Karl Popper.

Political Support for Relativity

Advocates of moral relativity seized on the theory of relativity to legitimize their views. Historians such as Paul Johnson wrote about how the theory of relativity caused a sea change, justified or not, in 20th century thought.

Relativity enjoys a disportionate share of federal funding of physics research today, much of it unsuccessful. The billion dollar LIGO project, for example, has failed to detect the gravity waves predicted by relativity.

Links

The Einstein Theory of Relativity, by H.A. Lorentz, http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm