It's much simpler to look at the fact that the big bang occored at one point, and from this fact it can be inferred that the center of the universe. This is where your logic comes into play; the opposite direction of the tragectory of any galaxy, star, or other celestial body starting from the point of said celestial body will take you to the center of the universe. So, in layman's terms, if you get next to a star, and go the opposite direction, you'll eventually find yourself at the center of the universe.
P.S. Bacterial worms have already been found on mars.