Changes

*Another is 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 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.  No Nobel Prize was was awarded for this.  Professor Pound had previously shared in the 1952 Nobel for his contributions to Nuclear Magnetic Resonance imaging.

*Later in the 20th century, even more subtle phenomena were tested.  One was the phenomenon of ''gravitational radiation'', or "gravitational waves".  These waves are incredibly difficult to observe, and had never been observed until 2015.  But extremely dense binary pulsars radiate gravitational waves with sufficient energy loss that, even though we can't detect the waves from Earth, we can see the effect of the energy loss from the radiation.  The extreme precision of the timing of pulses from pulsars makes it possible to observe their energy loss with great accuracy.  Observations by Hulse and Taylor of the pulsar pair known as B1913+16, if assumptions are made,<ref>Similar to the way Kepler chose orbital parameters to fit observed planetary motion to his theory</ref> could make the energy loss appear consistent with the predicted radiation.  The rotating pulsars have moved such that Earth is now out of the beams, so those observations have been discontinued.

*Later in the 20th century, even more subtle phenomena were tested.  One was the phenomenon of ''gravitational radiation'', or "gravitational waves".  These waves are incredibly difficult to observe, and had never been observed until 2015.  But extremely dense binary pulsars radiate gravitational waves with sufficient energy loss that, even though we can't detect the waves from Earth, we can see the effect of the energy loss from the radiation.  The extreme precision of the timing of pulses from pulsars makes it possible to observe their energy loss with great accuracy.  Observations by Hulse and Taylor of the pulsar pair known as B1913+16, if assumptions are made,<ref>Similar to the way Kepler chose orbital parameters to fit observed planetary motion to his theory</ref> could make the energy loss appear consistent with the predicted radiation.  The rotating pulsars have moved such that Earth is now out of the beams, so those observations have been discontinued.