2
votes
1answer
42 views

Distance from redshift

I am looking for a exact derivation of a relation between redshift $z$ and distance $d$. What I know is the definition ...
1
vote
1answer
335 views

Pulsar gravitational binding energy?

A Newtonian homogeneous density sphere has gravitational binding energy in Joules $U = -(3/5)(GM^2)/r$, G=Newton's constant, M=gravitational mass, r=radius, mks. The fraction of binding energy to ...