Time Travel in Einstein's Universe Quotes

“If you see an antimatter version of yourself running towards you, think twice before embracing.”
― J. Richard Gott, Time Travel in Einstein's Universe: The Physical Possibilities of Travel Through Time

“At the other extreme, if you are at the end of the middle 95 percent, you are situated just 2.5 percent from the end. In that case, 39/40ths of the interval are in the past and 1/40th of the interval remains in the future, making the future only 1/39th as long as the past. Thus, you can say with 95 percent confidence that you fall between these two extremes and that the future longevity of whatever you are observing lies between 1/39th and 39 times its past longevity (see Figure 31).”
― J. Richard Gott III, Time Travel in Einstein's Universe: The Physical Possibilities of Travel Through Time

“Because space and time have opposite signs, extra distance traveled in space on the way to that party means less time elapsed on your clock. You age less. This leads to the famous “twin paradox,” which is the key to time travel to the future.”
― J. Richard Gott III, Time Travel in Einstein's Universe: The Physical Possibilities of Travel Through Time

“But where did the watch come from? This watch is a jinni—elderly Miss McKenna gives it to the young playwright, who takes it back in time to deliver it to her as a young woman. She keeps it all her life until it is time to return it to him. So who made the watch? No one. The watch never went anywhere near a watch factory. Its world line is circular. Novikov has noted that in the case of a macroscopic jinni like this the outside world must always expend energy to repair any wear-and-tear (entropy) it has accumulated so it can be returned exactly to its original condition as it completes its loop. Permissible in theory, macroscopic jinn are improbable. The whole story in Somewhere in Time could have taken place without the watch. The watch seems particularly unlikely since it appears to keep good time. One could have imagined finding a nonworking watch or perhaps a paper clip that passes back and forth between the couple. How lucky to encounter a watch that works! According to quantum mechanics, if one has enough energy, one can always make a macroscopic object spontaneously appear (along with associated antiparticles, which have equal mass but opposite electric charge)—it’s just extremely unlikely. Similarly with jinn, it would be more improbable to find a watch than a paper clip and more improbable to find a paper clip than an electron. The more massive and more complex the macroscopic jinni, the rarer it will be.”
― J. Richard Gott III, Time Travel in Einstein's Universe: The Physical Possibilities of Travel Through Time