AST201H5 Lecture Notes - Lecture 7: Event Horizon, Solar Mass
Document Summary
Gain fresh mass, fusion on the surface -> nova explosion. Mass increases to the mass limit -> supernova explosion. Massive star supernova can create a neutron star with rapid rotation and an extreme magnetic field. Discovered as radio pulsars and x-ray binary stars. Neutron star mass cannot be more than 3 msun. A more massive object collapses to a point with infinite gravity. Escape speed becomes infinite > speed of light. Not even light can escape = black hole. This result is correct, but the explanation is wrong: Fg = g m1m2/d^2 = g m1 0 / d^2 = 0. Because light does not have a mass it feels no force of gravity -> it should still be able to escape. Einstein invented another explanation (a new theory of gravity) (1915 imporant. Gravity makes space bend: no gravity -> space is flat gravity -> space is bent. Infinite gravity -> space around the black hole closes off.
