The most acceptable sceince theory is that the world was created by two free roaming huge asteroids or something of that idea, collided.... formed a huge planet, after trillions of years of orbiting the sun, earth got its sphere shape.... then there were was a tiny life atom, or molecule floating in space, then one just happend to land on earth and slowly began marine life, then evolution took part and now were here.

Thats why people say there could be life on other universes, but the chance of one of those life/genetic molecules landing on 1 single planet is 1:4500000000x3000.... shows how lucky we are to exist at all.