||We always thought ourselves of being at the center of the Universe and at rest. It was not until very recently that Copernicus showed us how our Earth is orbiting the Sun and that the Sun, not the Earth, is at the center of our solar system. Today's theories such as Einstein's special and general relativity, still consider us and our galaxy, to be at the center of the Universe. In fact, relativity through its "cosmological principle" claims that any observer on any galaxy in the Universe can consider him or herself at the center and at rest. In other words, everything is relative and there is no preferred or absolute point in space to relate our location or frame of reference to, thus the term "relativity". This view creates certain problems. Imagine how difficult it was for astronomers before Copernicus' time, to set up mathematical equations for planetary orbits with the Earth at the center and at rest and how difficult it is today to deal with a Universe that has more than one center in which we can consider ourselves to be motionless and at rest. It is understandable why we tend to believe that we are at rest since the star studded sky seems motionless relative to us and we have no feeling or conception of velocity or acceleration. For example, we cannot feel that we are hurling through space around the Sun fifty times faster than a rifle bullet at an orbital velocity of 30 km/second (18 miles/second). Nor do we feel our velocity around the center of our galaxy which is ten times higher or our velocity relative to the rest of the Universe which is another thousand times higher and which equals c, the velocity of light.