Changes

*At the end of Einstein's original 1905 paper [http://www.fourmilab.ch/etexts/einstein/E_mc2/www/ "Does the Inertia of a Body Depend its Energy Content?"], he speculates on the possibility that the equation <math>E = m c^2</math>, which would normally be very hard to verify, could be verified with the extremely high energies of the newly-discovered phenomenon of radioactivity.<ref>This equation is not related to [[quantum mechanics]].</ref>  In the 1910's, with the invention of the mass spectrometer, it became possible to measure masses of nuclei accurately.  This led to the clearing up of the mystery of atomic masses not being exact integers,and strongly suggested the existence of a "mass defect" (or "packing fraction") consistent with the mass-energy equivalence.  In the 1930's, experiments with known nuclear reactions showed a very accurate correlation between the masses of the nuclei involved and the energy released.

*At the end of Einstein's original 1905 paper [http://www.fourmilab.ch/etexts/einstein/E_mc2/www/ "Does the Inertia of a Body Depend its Energy Content?"], he speculates on the possibility that the equation <math>E = m c^2</math>, which would normally be very hard to verify, could be verified with the extremely high energies of the newly-discovered phenomenon of radioactivity.<ref>This equation is not related to [[quantum mechanics]].</ref>  In the 1910's, with the invention of the mass spectrometer, it became possible to measure masses of nuclei accurately.  This led to the clearing up of the mystery of atomic masses not being exact integers,and strongly suggested the existence of a "mass defect" (or "packing fraction") consistent with the mass-energy equivalence.  In the 1930's, experiments with known nuclear reactions showed a very accurate correlation between the masses of the nuclei involved and the energy released.

*Another prediction of special relativity was time dilation in rapidly moving objects.  This effect was most famously verified in the anomalously slow decay of relativistic cosmic muons<ref>Some have suggested that other explanations are possible for this effect.  We are trying to track this down.</ref>.  Time dilation has since been verified many times, and is routinely taken into account in all high-energy nuclear physics experiments, as in Hadron collision experiments<ref>Experiments to check dilation are rarely conducted any more.</ref>.

*Another prediction of special relativity was time dilation in rapidly moving objects.  This effect was most famously verified in the anomalously slow decay of relativistic cosmic muons<ref>Some have suggested that other explanations are possible for this effect.  We are trying to track this down.</ref>.  Time dilation has since been verified many times, and is routinely taken into account in all high-energy nuclear physics experiments, as in Hadron collision experiments<ref>Experiments specifically designed to check dilation are rarely conducted any more.</ref>.

Predictions of general relativity turned out to be more obscure and difficult to test.  The two most famous predictions were the bending of light in a gravitational field and the precession of the perihelia of orbiting planets.

Predictions of general relativity turned out to be more obscure and difficult to test.  The two most famous predictions were the bending of light in a gravitational field and the precession of the perihelia of orbiting planets.

[[Image:Cassini-science-289.jpg|right|thumb|The Shapiro effect: A spacecraft signal dipping into a gravity well around the [[Sun]] is delayed slightly.]]

[[Image:Cassini-science-289.jpg|right|thumb|The Shapiro effect: A spacecraft signal dipping into a gravity well around the [[Sun]] is delayed slightly.]]

As the 20^th century progressed, more tests of general relativity were proposed. One was the ''Shapiro effect'', involving time delay in radio signals passing through the gravity well of the Sun or a planet.  Various spacecraft have confirmed this.

As the 20^th century progressed, more tests of general relativity were proposed.

 

*One was the ''Shapiro effect'', involving time delay in radio signals passing through the gravity well of the Sun or a planet.  Various spacecraft have confirmed this.

*Another is ''gravitational time dilation''.  This is an effect separate from the time dilation of special relativity.  It was tested by the Pound-Rebka experiment in 1959.

*Another is ''gravitational time dilation''.  This is an effect separate from the time dilation of special relativity.  It was tested by the Pound-Rebka experiment in 1959.