Orbiting a giant planet with (You name it) on it, when it exploded, sending millions of pieces of debris and stuff shooting into space, along with it's moon.
We are now finding things on mars, and if we could go to all the other planets we would find the same stuff, and if we dug deeper here we would find stuff we haven't even invented yet.
The explosion of the massive giant planet, threw it's moons out into an orbit around the sun, which is now our solar system.
Perhaps the BIG BANG
Jeff