## Wednesday, December 23, 2015

### Hubble-collapse

can you show that the density inside a sphere which contracts according to a Hubble-law $\upsilon(r)\propto -r$ remains homogeneous? what's the relation between density $\rho$ and time $t$?

we wish all our readers and followers merry x-mas and a happy and successful year 2016. we hope to see you again in january.

## Wednesday, December 16, 2015

if electrons are truly pointlike particles, would it be a problem for the field lines emanating from the charge to cross the Schwarzschild radius?

## Wednesday, December 9, 2015

### replacing Maxwell's equations

Maxwell's equations describe the sourcing and the time evolution of electric and magnetic fields. could you replace them with 1. charge conservation, 2. the Coulomb-law and 3. the Lorentz transformation for fields? would there be something missing?

## Wednesday, December 2, 2015

### gravitational wave interferometers

CQW celebrates its fourth anniversary!

imagine a Michelson-Morley-type interferometer for the detection of gravitational waves: are there directions in which it is insensitive to linearly polarised gravitational waves? what about circularly polarised gravitational waves?