What is the relative speed of two near-light speed particles headed towards each other?
12267
(Almost) double light speed
4350
Rotate a long bar in space and get close to (or even beyond) the speed of light $c$
2872
Kepler problem in time: how do two gravitationally attracted particles move?
56930
What would an observer see if he/she flew toward a clock at relativistic speeds?
132263
Pauli principle for particles very far apart from each other
22118
If all motion is relative, how does light have a finite speed?
974
Speed of light in a gravitational field?
66972
Is there any way to measure the one-way speed of light?
58503
Electrons moving faster than light and backward in time?
75158
Is acceleration relative?
19850
Why is the speed of light defined as 299792458 m/s?
4789
Apparent Violation of Newton's $3^{\text{rd}}$ Law and the Conservation of Momentum (and Angular Momentum) For a Pair of Charged Particles
45888
Minkowski metric -- why does it follow from the constancy of the speed of light?
45708
Why do far away objects appear to move slowly in comparison to nearby objects?
28488
I am confused about the idea that the speed of light is independent of the speed of the source of light
105142
What does general relativity say about the relative velocities of objects that are far away from one another?
115786
Speed of gravitational waves and light