## Wednesday, May 30, 2012

### black body in 4 dimensions

what would be a black body's flux-frequency relation in 4 spatial dimensions? in $n$ spatial dimensions? what would be equivalent relations for the Wien displacement law and the Stefan-Boltzmann law?

bonus question: what's $\mathrm{d}/\mathrm{d}x\: \mathrm{arcosh}(x)$?

## Wednesday, May 23, 2012

### selection bias - cosmo CSI

during the 1960's, criminal investigators were puzzled by an observation that in many countries with a seaside a considerable number of dismembered feet in sports sneakers were washed ashore. a logical explanation seemed to be a serial killer murdering joggers, but the truth is different and involves statistics, and the biasedness of observations: what would be your guess?

## Wednesday, May 16, 2012

### time-variation of the CMB

does the pattern of hot and cold patches of the CMB change in time? if yes, on what time scale?

bonus question: which parts of the CMB spectrum will gain in amplitude and which effects will loose in their importance?

## Thursday, May 10, 2012

### CDM particle properties

what statements about the properties of the dark matter particles can we make by observing cosmic structures?

## Thursday, May 3, 2012

### negative redshifts

would negative cosmological redshifts (aka blueshifts  ;) ) be useful to describe events in the future evolution of the Universe? if yes, what'd be the largest (most negative) redshift which can be defined in a sensible way?