Time Travel To The Future in Physics
There are various ways in which a person could "travel into the future" in a limited sense: the person could set things up so that in a small amount of his own subjective time, a large amount of subjective time has passed for other people on Earth. For example, an observer might take a trip away from the Earth and back at relativistic velocities, with the trip only lasting a few years according to the observer's own clocks, and return to find that thousands of years had passed on Earth. It should be noted, though, that according to relativity there is no objective answer to the question of how much time "really" passed during the trip; it would be equally valid to say that the trip had lasted only a few years or that the trip had lasted thousands of years, depending on the choice of reference frame.
This form of "travel into the future" is theoretically allowed (and has been demonstrated at very small time scales) using the following methods:
- Using velocity-based time dilation under the theory of special relativity, for instance:
- Traveling at almost the speed of light to a distant star, then slowing down, turning around, and traveling at almost the speed of light back to Earth (see the Twin paradox)
- Using gravitational time dilation under the theory of general relativity, for instance:
- Residing inside of a hollow, high-mass object;
- Residing just outside of the event horizon of a black hole, or sufficiently near an object whose mass or density causes the gravitational time dilation near it to be larger than the time dilation factor on Earth.
Additionally, it might be possible to see the distant future of the Earth using methods which do not involve relativity at all, although it is even more debatable whether these should be deemed a form of "time travel":
- Hibernation
- Suspended animation
Read more about this topic: Time Travel
Famous quotes containing the words time, travel, future and/or physics:
“Anybody who knows the difference between the kind of conversation you have walking in the woods and the kind of conversation you have between the segments of a show on Nickelodeon can tell you that quality time exists. Quality time is when you and your child are together and keenly aware of each other. You are enjoying the same thing at the same time, even if it is just being in a room or going for a drive in the car. You are somehow in tune, even while daring to be silent together.”
—Louise Lague (20th century)
“When you travel to the Celestial City, carry no letter of introduction. When you knock, ask to see God,—none of the servants.”
—Henry David Thoreau (1817–1862)
“Our Last Will and Testament, providing for the only future of which we can be reasonably certain, namely our own death, shows that the Will’s need to will is no less strong than Reason’s need to think; in both instances the mind transcends its own natural limitations, either by asking unanswerable questions or by projecting itself into a future which, for the willing subject, will never be.”
—Hannah Arendt (1906–1975)
“Although philosophers generally believe in laws and deny causes, explanatory practice in physics is just the reverse.”
—Nancy Cartwright (b. 1945)