14
Black Holes -- details
–
•Remember – gravity is same as before, away from mass
–Black holes do NOT necessarily pull all nearby material in
–A planet orbiting a new black hole would just keep on orbiting as before (assuming the ejected material or radiated energy didn’t have an effect)
–
•Any mass can potentially be made into a black hole – if you can compress it to a size smaller than RS = 2GM/c2
–1 MSun: 3.0 km        106 MSun 3´106 km          1 MEarth 8.9 mm
–
•If you do make material fall into a black hole, material will be falling at close to the speed of light when it reaches RS
–If that falling gas collides with and heats other gas before it reaches RS, then light from that hot material (outside RS) can escape.