Sagittarius A-Star's latest activity

The direction determines whether you see a lengthened or shortened eclipse. The speed (times the more-or-less constant duration of an...

The following shows, that Roemer measured a Doppler-effect. Source: https://www.mathpages.com/home/kmath203/kmath203.htm

The Abbe diffraction limit assumes an isotropic wavelength. The relativistic movement of a reference frame in longitudinal direction...

It makes no sence to speak of the perspective of a photon because a rest-frame of a photon does not exist.

I agree that in GR free-falling particles follow geodesics and experience no force by definition. My point was simpler (for...

If small bodies follow their geodesics, that is in GR not considered as an interaction force. Consider in flat spacetime two small...

That are in GR not gravitational interaction forces but electric forces within the extended object.

That's almost correct. It moves a distance ##a (1 \text{s})^2## ahead. Please see above.

That's wrong. Besides the fact, that the physical units on the left and right side of the equation are different, ##x(2s)## cannot be...

That would be in average the case for electrons in a resistor, but in the OP screenshot, the electron is - according to the problem - in...

##v(t) = \dfrac{a_0}{\omega} (1 -\cos\omega t)## Assume you repeat periodically: accelerate your car from 0 mph to 65 mph, then press...

A.T. gave an excellent answer in post #2, but perhaps the original question was even simpler than we made it: if a clock moves fast...

It should be noted that no matter what the axis of the local motion in the rocket is, over an entire local motion cycle it is slowed by...

Oh yes, he was a remarkable filmmaker! :smile: And I also like Barry Lyndon and The Shining. By the way, by coincidence a friend of...

The calculation result depends on the direction of movement of things in the moving frame. Assume the two coordinate systems in...