For years we’ve been told that someone who left point A and flew through space to point B at the speed of light, and then returned to point A would find that it was some god awful number of years later when they returned.
If you think about it, the whole theory doesn’t make sense at all, and here’s why.
Similar to my feelings on multiple time lines, I believe that time is constant, and this whole theory can be broken down by using the same methodology I used to come to my conclusions about time travel and multiple time lines.
So let’s say we have a spaceship. It takes off and flies out into space at light speed. It travels for let’s say 1 year at this speed and then stops on a planet, sets up a telescope and looks at the earth. What will they see? Right. They’ll see the Earth as it was exactly when they left, because they were traveling at the speed of light. Theoretically, if they traveled faster than the speed of light and had some kind of a super telescope, they would be able to look back at the Earth and actually see themselves taking off. If they merely traveled at the exact speed of light, they would see things continuing from the point at which they actually left the Earth, because the light they’re seeing is the same light that was leaving the Earth when they took off. It arrived at point B at the same time they did, so what they would see is in fact the moment they left, and on from there.
Now, in actuality, one year has passed, since it took them one year to make the journey. Perceptually, looking through that telescope, it wouldn’t look like any time had passed at all.
So they pack up their gear and return to earth at light speed. The return trip takes one year, and they arrive home. So how much time has passed? Right. Exactly two years has passed, because that’s how long they took to travel to point B and back. They didn’t travel back in time, or forward for that matter.
In fact, if they had the ability to observe point A constantly on the outgoing trip and the return trip, on the outgoing trip events at point A would appear to be frozen, and on the return trip, events would appear to be going at double speed because they’re traveling at light speed back against the outgoing light from point A, which is traveling at light speed in the opposite direction. So when they got back to point A, it would all be synced up again and the travelers would return to real-time perception.
Now, there really is no way to use speed of light travel to go back in time, simply because you would have to go way faster than the speed of light, and then be able to look back at your point of origin to be able to see what happened in the past, which is pretty much impossible and always will be unless they can figure out a way to bend space back on itself to allow for a shortcut in the perception of the light emanating from point A, which would most likely never happen.
Is time travel impossible? Who knows? I don’t think so, but it’s certainly not achievable by means of faster than light travel, because that’s not real time travel. That’s very literally nothing more than waiting for the light to catch up with you at your current location. If that were real time travel, then we’d all be time travelers. If you look up at the moon, you’d see where it was a few minutes ago, because it takes a few minutes for the light reflecting off of it to reach the Earth. So you’re literally seeing what the moon looked like and where it was in the past. That doesn’t make you a time traveler, it just makes you far enough away from the moon that the light can’t get to you instantaneously, and yet you’re looking at a past event.
Time is both perceptual and constant. From the human, relativistic standpoint, it’s perceptual, and from a universal standpoint, it’s constant. The moon example is a good one. We perceive the moon to be in a position it was in several minutes ago, while the moon has in fact traveled a great distance from where we perceive it to be. From the moon’s perspective however, it’s right where it should be, because it’s operating in real time, while because of the lag in the time it takes for the light reflecting off it to reach Earth, we’re only left with an outdated perception of it’s current, real-time position.
I know it’s a deep concept and I don’t know if I really explained it well, but it was just something I’ve been thinking about recently, and I felt like I needed to get it out there.(Current Mood: thoughtful)