|How fast is the earth moving through space? Does this movement affect our perception of time? — GR, Grabil, IN
Because there is no preferred reference frame for the universe, we can only talk about the earth's speed in reference to other objects. For example, the earth is moving at about 5 kilometers per second relative to the sun and about 30,000 kilometers per second relative to the center of the galaxy. These speeds do affect our perceptions of time, so that times passes at a different rate for us than for someone closer to the sun or to the galactic center. However, gravitational wells also affect the perception of time, so that the effects are complicated. The earth is also receding extremely rapidly from objects at the far side of the universe; so fast that time passage is dramatically affected. Those distant objects appear to be aging very slowly and their light is shifted substantially toward the red.