Well, that depends.<br />
I bet Einstein did it all by himself, but for Stephen Hawking, it might take two people...
Depends on the reference point.
O frak. I thought this said "how long" like the other light bulb questions. :o(
Three. 1 to hold the light bulb in place and 2 to turn the universe.
one clever one.
your'e looking crafty today....
none...they're used to stumbling around in the dark...guessing.
ZERO. They will over and over and over analyze this to death, while paying the janitor minimum wage to replace it. They will still be talking about the possibilities of what may or may not happen once it has been changed.