"that in order for our planet to have survive as a 'living' planet, it should have been formed at the right place, at the right time...
the discovery of the first exosolar planet has made this theory possible:
the earth first formed very close to the sun (closer than when pluto is right now), then as it gained mass, it started to drift away, and got knocked out by the still forming jupiter (currently the largest planet) which was 2 times the mass of the still forming earth.
after drifting farther off, the planet was stabilized by the drifting uranus and mars fixing it into it's position, a vey thin boundary that formed right after every planet that formed was fixed into position. (the planet is actually centered in this thin film, and moving off course by a mile in any direction will knock us out of this thin film (which is relatively small in consideration to our planet's size) that has exactly the right temperature enough to support life... moving a mile further will freeze us, and moving a ile closer will burn us...)