No time travel into the future or into the past is not possible. Before I get a thumbs down from my colleagues for the not into the future statement, please check out my reasoning below.
Both the special and general theories of relativity show how the rate of time can be slowed to dt < dT where dT is some standard rate of time, typically Earth time.
For example, if you were traveling V = .8C relative to Earth, your rate of time would be dt = dT sqrt(1 - .8^2) = .6 dT; so for every dT = 1 second back on Earth your Rolex would advance only dt = .6 seconds. That very expensive wristwatch is losing time; not because it's defective but because of so-called time dilation of the special theory of relativity. [There is also one from the general TOR.]
If you flew to Alpha Centauri and back at .8C, you'd be gone from Earth about dT = ten years. But your calender would show being gone for only six years. So when you hopped off back on Earth with the loaf of Centaurian bread your spouse sent you out for, you'd be instantaneously four years ahead of your own calender. Some say that's fours years travel into the future.
I don't agree. You didn't go into the future, you just caught up with the present.
Earth time is the standard against which the spaceship time is measured. That's so because your speed V = .8C is measured relative to the Earth and that makes it the reference frame, the standard for space, time, and speed. And that means Earth time is the present and when you hop off the ship you simply catch up to the present, EST, Earth Standard Time.
This is consistent with the concept that time is simply the unfolding of events. And the only time is the current time while the events are currently happening. Events that are done no longer exist. There is no past (one of the many reasons you can't go there). And events that are yet to happen do not exist either; so there is no future time. You can't really go into the future either. And that leaves us solely with the now, the present; and that you can catch up to after lagging behind on that spaceship.
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I have already answered this question four years from now.
So, no and twice its length divided by two.
No time travel into the future or into the past is not possible. Before I get a thumbs down from my colleagues for the not into the future statement, please check out my reasoning below.
Both the special and general theories of relativity show how the rate of time can be slowed to dt < dT where dT is some standard rate of time, typically Earth time.
For example, if you were traveling V = .8C relative to Earth, your rate of time would be dt = dT sqrt(1 - .8^2) = .6 dT; so for every dT = 1 second back on Earth your Rolex would advance only dt = .6 seconds. That very expensive wristwatch is losing time; not because it's defective but because of so-called time dilation of the special theory of relativity. [There is also one from the general TOR.]
If you flew to Alpha Centauri and back at .8C, you'd be gone from Earth about dT = ten years. But your calender would show being gone for only six years. So when you hopped off back on Earth with the loaf of Centaurian bread your spouse sent you out for, you'd be instantaneously four years ahead of your own calender. Some say that's fours years travel into the future.
I don't agree. You didn't go into the future, you just caught up with the present.
Earth time is the standard against which the spaceship time is measured. That's so because your speed V = .8C is measured relative to the Earth and that makes it the reference frame, the standard for space, time, and speed. And that means Earth time is the present and when you hop off the ship you simply catch up to the present, EST, Earth Standard Time.
This is consistent with the concept that time is simply the unfolding of events. And the only time is the current time while the events are currently happening. Events that are done no longer exist. There is no past (one of the many reasons you can't go there). And events that are yet to happen do not exist either; so there is no future time. You can't really go into the future either. And that leaves us solely with the now, the present; and that you can catch up to after lagging behind on that spaceship.
If you are going to have traveled in time, you will needed to study verb tenses.
Time travel is not possible.
And learn grammar.
use Einstein's special and general relativity to build a time machine, shouldn't be too hard
It is not possible.