## Wednesday, February 24, 2016

### speed of light and speed of gravity

can you explain why electromagnetic and gravitational waves travel at the same speed?

## Wednesday, February 17, 2016

### negative cosmological constant

could $\Lambda$ be negative? what consequences would that have for the evolution of FLRW-universes and would it be conceivable from a theoretical point of view?

## Wednesday, February 10, 2016

### curved or straight?

please list as many experiments as possible that would allow you to distinguish between curvature and dark energy with an equation of state of $w=-1/3$.

## Wednesday, February 3, 2016

### correlation function

can you show that the integral $\int\mathrm{d}^nx\:C(r)$ of the correlation function $C(r)$ as a function of distance $r$, $r^2=\sum_{i=1}^n x_i^2$, of a random field in $n$ dimensions vanishes?