Recent content by undidly

""curve a bed spring,"" I think you mean a bed mattress. Imagine a mattress in the shape of a hollow sphere. Make it spin. Centrifugal force will make any masses inside press into the mattress. These are the analogy with the curvature of space. The masses roll or slide into each others...

You are right .You did say group velocity. The faster than light propagation of a photon in the special material sounds like a trick of words. As the photon enters the material the peak is at the back?. As the front of the photon leaves the material the peak is at the front,a different wave...

"" Negative group velocity would mean that, say, the peak of the wavepacket exits the material before it enters."" It does not mean that. Waves build up at the front of the photon and move backwards through the photon until they fade away at the back of the photon. Positive phase...

Give away as many organs as you can. In the future when cloning is legal you can be reborn from the DNA in the donated organs. No memories of course but the same physical type and personality. New you would also inherit all your wealth,leave it all to yourself. Invested money would earn interest...

How is it possible to measure the phase velocity of a photon (light wave)?.

How would an experimenter detect a graviton?. Can they travel at any speed or just the speed of light (like a gravitational wave)?.

I read of an experiment to detect monopoles. The equipment was a superconducting ring. If a bar magnet is dropped through the ring longways the first pole induces a voltage that causes a circulating current.The second pole induces a reverse voltage which exactly cancels the current from...

What about gravitational waves if they exist?. The moving particles in the diagrams move in many directions under the influence of the waves. The waves must have a longitudinal component ,strong /weaker attraction ,if they are from binary star pair observed edge on as each star moves...

Do your own experiments. Take the top cover off a computer hard disk drive and plug it back into the power leads.RBBY. Switch on the computer and see the disc spinning,just like a Tesla smooth disc. Drill two holes in the top cover ,one in line with the disc center and another at the edge of...