Changes

A decade of observation of the [[pulsar]] pair [[PSR 1913 16|PSR B1913+16]] detected a decline in its orbital period, which was attributed to a loss in energy by the system.  It is impossible to measure the masses of the pulsars, their accelerations relative to the observers, or other fundamental parameters.  Professors Joseph Taylor and Russell Hulse, who discovered the binary pulsar, found that physical values could be assigned to the pulsars to make the observed decline in orbital period consistent with the Theory of General Relativity, and for this they were awarded the 1993 [[Nobel Prize]] for Physics, which is the only award ever given by the Nobel committee for the Theory of Relativity.<ref>http://nobelprize.org/nobel_prizes/physics/laureates/1993/press.html</ref> In 2004, Professor Taylor utilized a correction to the derivative of the orbital period to fit subsequent data better to the theory.  At most, assumptions can be made and altered to fit the data to the theory, rather than the data confirming the theory.

A decade of observation of the [[pulsar]] pair [[PSR 1913 16|PSR B1913+16]] detected a decline in its orbital period, which was attributed to a loss in energy by the system.  It is impossible to measure the masses of the pulsars, their accelerations relative to the observers, or other fundamental parameters.  Professors Joseph Taylor and Russell Hulse, who discovered the binary pulsar, found that physical values could be assigned to the pulsars to make the observed decline in orbital period consistent with the Theory of General Relativity, and for this they were awarded the 1993 [[Nobel Prize]] for Physics, which is the only award ever given by the Nobel committee for the Theory of Relativity.<ref>http://nobelprize.org/nobel_prizes/physics/laureates/1993/press.html</ref> In 2004, Professor Taylor utilized a correction to the derivative of the orbital period to fit subsequent data better to the theory.  At most, assumptions can be made and altered to fit the data to the theory, rather than the data confirming the theory.

The [[perihelion]] of Mercury's [[orbit]] [[precession|precesses]] at a measurable rate, but even after accounting for gravitational perturbations caused all other planets in the [[solar system]], Newton's theory (assuming a precise inverse-square relationship for distance) predicts a rate of precession that differs from the measured rate by approximately 43 [[arcsecond]]s per century.  General relativity was developed in part to provide an estimate for this rate of precession that better matches observations.<ref>http://physics.ucr.edu/~wudka/Physics7/Notes_www/node98.html#SECTION032121000000000000000</ref><ref>http://www.alberteinstein.info/gallery/pdf/CP6Doc30_English_pp146-200.pdf</ref><ref>http://farside.ph.utexas.edu/teaching/336k/lectures/node117.html</ref>  Newton's theory can also explain this perihelion by making tiny adjustments to parameters in the gravitational equation.

The [[perihelion]] of Mercury's [[orbit]] [[precession|precesses]] at a measurable rate, but even after accounting for gravitational perturbations caused all other planets in the [[solar system]], Newton's theory (assuming a precise inverse-square relationship for distance) predicts a rate of precession that differs from the measured rate by approximately 43 [[arcsecond]]s per century.  While general relativity was developed on purely theoretical grounds, it was soon discovered that it explained these precession observations.<ref>http://physics.ucr.edu/~wudka/Physics7/Notes_www/node98.html#SECTION032121000000000000000</ref><ref>http://farside.ph.utexas.edu/teaching/336k/lectures/node117.html</ref>  Newton's theory can also explain the Mercury precession by making tiny adjustments to parameters in the gravitational equation, but doing so would give the same precession for all orbiting bodies everywhere, a phenomenon which is not observed.

General relativity predicts twice as much bending in light as it passes near massive objects than Newton's theory might predict.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> This phenomenon is known as [[gravitational lensing]]. A large number of instances of gravitational lensing have been observed, and it is now a standard astronomical tool.<ref>http://imagine.gsfc.nasa.gov/docs/features/news/grav_lens.html</ref><ref>http://astro.berkeley.edu/~jcohn/lens.html</ref><ref>http://www.iam.ubc.ca/~newbury/lenses/glgallery.html</ref>  Note, however, that the extent of bending of light predicted by Newton's theory is open to debate, and depends on assumptions about the nature of light for gravitational purposes.<ref>http://cosmictimes.gsfc.nasa.gov/1919/guide/gravity_bends_starlight.html</ref>

General relativity predicts twice as much bending in light as it passes near massive objects than Newton's theory might predict.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> This phenomenon is known as [[gravitational lensing]]. A large number of instances of gravitational lensing have been observed, and it is now a standard astronomical tool.<ref>http://imagine.gsfc.nasa.gov/docs/features/news/grav_lens.html</ref><ref>http://astro.berkeley.edu/~jcohn/lens.html</ref><ref>http://www.iam.ubc.ca/~newbury/lenses/glgallery.html</ref>  Note, however, that the extent of bending of light predicted by Newton's theory is open to debate, and depends on assumptions about the nature of light for gravitational purposes.<ref>http://cosmictimes.gsfc.nasa.gov/1919/guide/gravity_bends_starlight.html</ref>