Changes

In late 2015 (and announced in 2016), the LIGO instruments directly detected gravitational waves allegedly from colliding [[black hole]]s.  See [[Gravitational waves]].  Unlike the waves from orbiting pulsars, that could only be detected by the loss of rotation energy, the waves from colliding black holes were strong enough to be detected directly.  The assumptions required for this, in addition to those listed above, were that the objects emitting the radiation (generally believed to be black holes, of course) satisfy the Schwartzschild solution to relativistic mechanics.  The 2017 Nobel Prize in physics was awarded for this.

In late 2015 (and announced in 2016), the LIGO instruments directly detected gravitational waves allegedly from colliding [[black hole]]s.  See [[Gravitational waves]].  Unlike the waves from orbiting pulsars, that could only be detected by the loss of rotation energy, the waves from colliding black holes were strong enough to be detected directly.  The assumptions required for this, in addition to those listed above, were that the objects emitting the radiation (generally believed to be black holes, of course) satisfy the Schwartzschild solution to relativistic mechanics.  The 2017 Nobel Prize in physics was awarded for this.

Since that very early announcement, further observations of gravitational waves have continued to come in.<ref>https://ligo.org</ref>  In August 2019 the first detection of the gravitational waves from the merger of a [[black hole]] and a neutron star occurred.  This was event S190814bv, 870 million light years away, and hence actually occurred 870 million years ago.<ref>https://www.extremetech.com/extreme/296902-scientists-detect-first-ever-collision-between-black-hole-and-neutron-star</ref>

Since that very early announcement, further observations of gravitational waves have continued to come in.<ref>https://ligo.org</ref>  In August 2019 the first detection of the gravitational waves from the merger of a [[black hole]] and a neutron star occurred.<ref>https://ligo.org/news/index.php#O3updateAug19</ref> This was event S190814bv, 870 million light years away, and hence actually occurred 870 million years ago.<ref>https://www.extremetech.com/extreme/296902-scientists-detect-first-ever-collision-between-black-hole-and-neutron-star</ref>

In 2018 an observation of the 3-body system PSR J0337+1715, consisting of 2 white dwarfs and a pulsar, was consistent with (and hence tended to confirm) general relativity under conditions of extremely high gravity, to enormous precision.  The assumptions made were the same as those listed above.  One of the researchers stated "If there is a difference [between observation and the prediction of the Equivalence Principle], it is no more than three parts in a million."<ref>https://www.nbcnews.com/mach/science/einstein-s-theory-relativity-passes-its-toughest-test-yet-ncna889021</ref>

In 2018 an observation of the 3-body system PSR J0337+1715, consisting of 2 white dwarfs and a pulsar, was consistent with (and hence tended to confirm) general relativity under conditions of extremely high gravity, to enormous precision.  The assumptions made were the same as those listed above.  One of the researchers stated "If there is a difference [between observation and the prediction of the Equivalence Principle], it is no more than three parts in a million."<ref>https://www.nbcnews.com/mach/science/einstein-s-theory-relativity-passes-its-toughest-test-yet-ncna889021</ref>