Comic-strip hero Superman meets an asteroid in outer space....?

Comic-strip hero Superman meets an asteroid in outer space and hurls it at 100 m/s. The asteroid is a thousand times more massive than Superman is. In the strip, Superman is seen at rest after the throw. Taking physics into account, what would be his recoil speed? What is this in miles per hour?

Since Supe obeys a whole different set of physical laws, being from the planet Krypton, he can pretty much do as he likes in our physical universe. Obviously he's got the gravity thing beat since he can fly, so he could, in theory, put the kibosh on all of Newton's equations.

Momentum = Mass * Velocity.

The asteroid would have a momentum of 1000 supermans * 100 m/s

So 100000 in our mystery units. Because of Newton's Third Law that states every action has an equal and opposite reaction, superman would be thrown backwards with the same force. We know he is one superman mass so we use the same equation again to find how fast he is going by putting his speed on one side of the equation

100000 = 1 superman * Recoil Speed(m/s)
Speed = 100000 / 1 superman = 100000 m/s
Convert that into MPH on your own.
That is fast!