Time travel is the concept of moving between different points in time in a manner analogous to moving between different points in space. Time travel could hypothetically involve moving backward in time to a moment earlier than the starting point, or forward to the future of that point without the need for the traveler to experience the intervening period (at least not at the normal rate). Any technological device – whether fictional or hypothetical – that would be used to achieve time travel is commonly known as a time machine.
Although time travel has been a common plot device in science fiction since the late 19th century and the theories of special and general relativity allow methods for forms of one-way travel into the future via time dilation, it is currently unknown whether the laws of physics would allow time travel into the past. Such backward time travel would have the potential to introduce paradoxes related to causality, and a variety of hypotheses have been proposed to resolve them, as discussed in the sections Paradoxes and Rules of time travel below.
Read more about Time Travel: Theory, In Physics, Time Travel To The Future in Physics, Philosophical Understandings of Time Travel
Famous quotes containing the words time and/or travel:
“Slow, slow, fresh fount, keep time with my salt tears;
Yet slower yet, oh faintly gentle springs:
List to the heavy part the music bears,
“Woe weeps out her division when she sings.”
Droop herbs and flowers;
Fall grief in showers;
“Our beauties are not ours”:
Oh, I could still,
Like melting snow upon some craggy hill,
Drop, drop, drop, drop,
Since nature’s pride is, now, a withered daffodil.”
—Ben Jonson (1572–1637)
“There is the grand truth about Nathaniel Hawthorne. He says NO! in thunder; but the Devil himself cannot make him say yes. For all men who say yes, lie; and all men who say no,—why, they are in the happy condition of judicious, unincumbered travellers in Europe; they cross the frontiers into Eternity with nothing but a carpet-bag,—that is to say, the Ego. Whereas those yes-gentry, they travel with heaps of baggage, and, damn them! they will never get through the Custom House.”
—Herman Melville (1819–1891)