Stephen Hawking, the eminent physicist, pointed out to his friend George Lucas that the original Star Wars Rebel fighter design, the J-Wing, would fly round and round in circles. Lucas set a team of researchers to discover the best letter and thus the X-Wing was born. However, Hawking failed to warn Lucas that the Empire's TIE Fighters were as unfeasible as the J-Wing. In real life the gravitational forces generated by a TIE Fighter's engines would cause all matter in the universe to compress to the size of a pea, effectively reversing the Big Bang. Lucas broke off the friendship and has not spoken to Hawking since. That is why ridiculous letter spaceships like the Y-Wing and the A-Wing appeared in later Star Wars films.