Time travel

Time travel is the concept of moving forward and backward to different points in time, much as we do through space. It also includes traveling sideways in time between parallel realities or universes.

"Distance" of time travel

According to special relativity, the physical laws may be invariant over Lorentz transformations. This mixes time and space dimensions as time can be compared to a distance times the speed of light. So, the second is comparable to a unit of distance equal to 299,792.458 kilometres. Conversely, the distance of 1 metre is comparable to about 3.34 nanoseconds. You can also compare a "year" to a "light-year" (since the square of a distance has the opposite sign to the square of a time, time and space are not actually identical).

Related Topics:
Special relativity - Invariant - Lorentz transformation - Kilometre - Metre - Nanosecond - Light-year

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Now, if we suppose that the same distances in space and time present the same level of technical difficulty, then moving in time for just one second, forward or backward, would be like flying to the Moon. Moving for a few years would be like flying to some of the nearest stars. And if you want to go visiting dinosaurs, perhaps it would be like flying to a far-off galaxy. On the basis of the above argument, some people think that time travel will require a lot of energy (unless we use something like teleportation).

Related Topics:
Moon - Star - Dinosaur - Galaxy - Energy - Teleportation

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