# What would be the exhaustive list of physical phenomena predicted or explained by special and general relativity?

I am trying to understand special and general relativity and I want to make sure that I didn't miss a physical ("real") phenomenon that is described by their equations, including the implied older predictions and explanations from Newtonian physics. The ones I know of are:

• Constant speed of light (and absence of simultaneity)

• Time dilation

• Length contraction

• Gravitational "force"

• Gravitational time dilation

• Gravitational lensing

But I am pretty sure I am missing some if not a lot of other phenomena.

• Gravitational waves. I don't know if that makes a full list, but everything that comes to mind is from applying the listed behavior to specific circumstances. May 24, 2017 at 5:56
• I'd like to make clear that relativity doesn't explain constance of the speed of light. It postulates it. In fact that is the starting point of special relativity May 24, 2017 at 6:47

## 1 Answer

Here's a list of various effects then (I might add more later on)

Measured effects for special relativity :

• The constancy of the speed of light, as measured by the Michelson-Morley experiment.
• Time dilation/length contraction of two observers in motion relative to each other, as measured by cosmic muon decay rates and atomic clocks on airplanes
• The relativistic energy momentum conservation laws, as verified by scattering expeirments.
• The relativistic Doppler effect, measured by the Ives–Stilwell experiment
• The (local) isotropy of space, as measured in the Hughes–Drever experiment
• The Sagnac effect, where the travel time of two light rays going in opposite directions is different if there is rotation involved, as measured in the Fizeau experiment.
• Relativistic corrections to quantum mechanics, such as the Lamb shift
• CPT invariance for quantum field theory, so far holding for all measurements.
• Lorentz invariance leading to a lack of the anomalous dispersion of light, measured on far off light sources

Other special relativistic effects :

• The relativistic aberration

Measured effects for general relativity :

• All predictions of classical gravitational theory (within some limits). These include :
• Attraction of two masses, as measured in the Cavendish experiment and the Schiehallion experiment
• The equivalence principle (objects dropped in a vacuum fall at the same rate), as confirmed in the Eötvös-Dicke experiment
• Tidal forces
• Shifting in quantum energy levels, as measured by ultra cold neutron experiments
• Light deflection around stars, as measured by Eddington.
• More generally, gravitational lensing, such as observed in the Einstein cross.
• The precession of the perihelion of Mercury
• Redshifting of light in a gravitational field, as measured in the Pound-Rebka-Snider experiment and in measurements of the spectrum of Sirius B.
• Time dilation in gravitational fields
• Frame dragging and geodetic precession, as measured by Gravity Probe B
• Gravitational waves, both indirectly by loss of energy in binary star systems and directly with LIGO
• The cosmological expansion of space, as measured by the redshifting of galaxies.

Effects that are currently not experimentally verified :

• Unruh radiation, where an accelerated observer will measure radiations where none exist for an observer at rest.
• Hawking radiations where an event horizon radiates thermal particles.
• The photon sphere around a black hole, which the Event Horizon Telescope will attempt to measure
• Creation of particles by non-static spacetimes (for instance by the cosmological expansion)