If the Sun were magically to turn into a black hole of the same mass, (a) Earth would start to spiral inward; (b) Earth's orbit would remain unchanged; (c)Earth would fly off into space; (d) Earth would be torn apart by the black hole's gravity.

If the sun were half as massive (M=0.5) then the period of the Earth's orbit would be: 1) 0.5 years 2) 0.7 years 3) 1.4 years 4) 0.4 years

If the sun were twice as massive (M = 2) and Earth were the same distance away (r =1) then the period of the Earth's orbit would be: 1) 0.5 years 2) 0.7 years 3) 1.4 years 4) 0.4 years

A black hole is an object so massive that not even light can escape, one way to define the size of a black hole is by the Schwarzschild Radius, which is the radius at which the escape velocity is equal to the speed of light. If we were to condense the Earth into a black hole, what would be the size of its Schwarzschild Radius?