What Happens to Earth if Sun Becomes a Black Hole?

[linnus]

I have no idea where this goes...
But I have a question. Say if the sun was big enough to turn into a black hole, what will happen to the earth? Will it stay in the same orbital path or will it be suck in by the black hole? Thanks

 

[wysard]

Did this problem with my dad some years ago. If the sun turned into a black hole (assume some magical shriking device or whatever to reduce the sun to a size less than 2km while retaining it's mass)

If it happened instantly the result would be that the sun would go out and we all freeze to death. But it would stay a frozen ball in the same orbit.

The questions happen when you ask, How? Why? Over what length of time? The answers to these questions tell you what happens to other nearby objects. Just for peace of mind, the sun will never become a black hole. As a main sequence G class star in its mass class it will go the Red Dwarf route. Bad for the moon, and then Earth in the long term, but not as spectacular. Sigh. Guess old Sol is just a blue collar worker in the solar world...lol