The diameter of my observable universe is 90 billion ly measured in proper distance. But isn't lenght a relative quantity in the theory of Relativity? Could an observer moving at a different velocity ...
As I know, for example the modelling of the collapse of a neutron star (to a black hole) wasn't done correctly until now. Why? Yes, I know, the Einstein Field Equations aren't really easy to solve. ...
Are there sufficient observational data to measure non-Newtonian perihelion advances of any Asteroid and Comet orbits?
Anomalous (i.e. not predicted from Newtonian theory) advances of the perihelion direction have been observed for many solar system planet orbits and have been accounted for by Einstein's General ...