Book excerpt: A Question of Time: The Ultimate Paradox by the Editors of Scientific American "What time is it?" That simple question is probably asked more often in contemporary society than ever before. In our clock-studded world, the answer is never more than a glance away, and so we can blissfully partition our days into ever smaller increments for ever more tightly scheduled tasks. Modern scientific revelations about time, however, make the question endlessly frustrating. If we seek a precise knowledge of the time, the infinitesimal flash of now dissolves into a scattering flock of nanoseconds. Because we are bound by the speed of light and the velocity of nerve impulses, our perception of the "present" reflects the world as it occurred an instant ago – for all that human consciousness pretends otherwise, we can never catch up. Even in principle, perfect synchronicity escapes us. Relativity dictates that, like a strange syrup, time flows slower on moving trains than in the stations and faster in the mountains than in the valleys. The time for our wristwatch is not exactly the same as the time for our head. This eBook, A Question of Time, summarizes what science has discovered about how time permeates and guides both our physical world and our inner selves. That knowledge should enrich the imagination and provide practical advantages to anyone hoping to beat the clock, or at least to stay in step with it. Synchronize your watches...