CQW is an educational resource for theoretical physics and astrophysics, field theory, relativity and cosmology. we post a new question every wednesday for students to get and for teachers to stay in shape.
Wednesday, January 30, 2013
gravity in 2d and 3d
why can't gravity rotate galaxy images in gravitational lensing, but introduce physical rotation of galaxies?
bonus question: where's the global minimum of $x^x$, $x>0$?