Why the average yearly temperature at the north pole is -18c while the average yearly temperature at the equator is 27c?

This is due to the tilt in the earth's axis, along with the pole's being a bit further from the sun. The shallow angle of the sun on the north pole means a lot of the heat energy is refracted away from the surface, and hardly any radial heat occurs. However, at the equator, the suns rays are much more direct, and the extremely steep sun angle allows radial heating to occur at high levels.

It might. it might because if you think about if they discovered if we came from (lets say something funny like aliens) and thy found cells that matched and they would have t do more research about it but would most probably change their theory.