Wednesday, July 30, 2014

CQW holiday project: NFW-wave function

what's the wave-function of a quantum mechanical particle inside an NFW-potential?

with that question, we would like to wish all our readers a nice summer vacation and hope to see you again in October. if you'd like to contribute to CQW with a question, please contact us at cosmologyquestionoftheweek["AT"]gmail["DOT"]com.

Wednesday, July 23, 2014

Roche limit for a drop of water

can you compute the Roche limit, i.e. the closest distance at which an orbiting object can approach a central body without being disintegrated by tidal forces, for the case that the orbiting object is held together by surface tension instead of gravity?

Wednesday, July 16, 2014

periapsis recession

what would the shape of relativistic corrections to the gravitational potential need to be such that one would observe a periapsis recession instead of a periapsis advance in an orbiting object?

Wednesday, July 9, 2014

units of spectra

can you please show that the unit of the fluctuation spectrum $P_\phi$ of a field $\phi(\vec{x})$ is given by the unit of the variable $\vec{x}$ on which the field depends to the power of the dimension of the space on which the field is defined times the squared unit of the field amplitude?

Wednesday, July 2, 2014

a much smaller Planck-mass

could you define a set of Planck-units based on the speed of light $c$, the Planck-constant $\hbar$ and instead of the gravitational constant $G$ the cosmological constant $\Lambda$? what would the numerical values be?