What does this mean for mass measurements? Basically the reason we can't travel faster then C (afaik) is because of the way relativistic velocities add. ie .8c +.2c +.2c +.2c = .935 c or something ...

Einstein’s Special Theory of Relativity (STR) is broadly misunderstood by the public. In most popular science books, relativity theory is hailed for introducing relativity to physics. Whereas ...

This PSSC film made in 1960 is one of the finest physics films ever made. All students should see it at some point in their studies. See the article '"Frames of Reference" revisited' by Alistair Steyn ...

We use methods of differential astrometry to construct a small field inertial reference frame stable at the micro-arcsecond level. Such a high level of astrometric precision can be expected with the ...