Not necessarily. It is possible that a wormhole could be found closer. There are theories that wormholes have exsist on our own planet. For example, it is one of the theories behind the Bermuda Triangle. The issues that leads to the disapppearances, ghost ships and what not. The theory is that a WH exsists at this location. Some say that the WH goes through the Earth, leading to what is known as the Dragon's Triange, the Pacific Ocean's version of the Bermuda Triangle. So when something is drawn through one entrance, it is then spit out the other side and leads to odd sightings and missing ships. There are also some theories that some ancient civilizations had WH's that connected them to alien cultures. Yes, like Stargate, but the one that I heard about was among the South American natives. I hesitate to go too far into this one as I cannot remember which of the ancient cultures has this sort of gateway set in stone among their ruins. I'm not saying that they claim its a WH, its just that the legend says that this stone was the gateway which their gods decended from the stars. I watched it on a History Channel show called Ancient Aliens so I would have some difficulty finding the source of this info.
Another possibility is faster than light travel, although this would be more one way rather than being able to move back and forth. The same goes for types of stasis that a person can be put into. I would look more toward dimentional jumping for time travel. Slipping through a crack between realities could occur by accident or through an item that finds cracks that can be then slipped through. Assuming that time is not a constant across the realities, this would allow you to interact with a history like our own, without the danger of erasing like as we know it.
Not good enough? You actually want to go into the past, ok then. Now if you look at time the way that Hindus view it, time does not travel in a straight line but is in fact overlaping circles. Wibbly wobbly timey wimy stuff, to quote the Doctor. As time can turn around on itself, slipping across the barrier of time. Again, there could be cracks or even a pocket of void space that one can slip into in order to move backwards into the former time. If you don't want it to happen by accident, there would have to be a way to find these places. Finding them would also serve in getting you back, unless you want to stay in the the 1950's with its poodle skirts and horribly inefficient cars.
I'm sure that I could think of more ways but I am really tired and I think I want to go to bed. I am also looking forward to what other people come up with
Time travel to the future is relatively (Einstein pun) easy. All you have to do is go really fast, like almost the speed of light. What will seem like a short amount of time for you will be a longer amount of time for everyone else. So When you stop moving, you will have gone farther along the arrow of time than anyone else, even though it didn't feel like it. Scientists today could even calculate how fast you would have to go, and for how long, in order to reach a specific date in the future.
Time travel to the past is an entirely different thing. I don't think any methods for this have been proven, although there are many convincing theories.
The nearest star is 4.5 lightyears away right, so from our perspective a photon would spend 4.5 years in order to reach us from there... But how much time does it take the photon to reach us from it's own perspective? Do you know? Or put differently, when does it arrive here relative to when it left it's star? I have hard time wrapping my head around this time relativity thingy... How significant is it?
Einstein's special theory of relativity is kind of complicated, so I can't really explain it. But according to his theory, which has been proven many times, when you travel the speed of light you actually feel no time compared to everyone else. If a photon was conscious, it would feel like it got to the earth instantaneously. It would have gone 4.5 years into the future compared to everyone else, while it felt zero time. This is what led Einstein to the conclusion that the speed of light is the speed limit of the universe.
Another way of looking at it is that there are four dimensions, three space and one time. If you are not moving in the space dimensions, you are moving at the speed of light in the time dimension. If you move through the space dimensions, you move at a slower speed in the time dimension. If you add up all of your speeds in all of the dimensions, you get the speed of light.
And, the effects of relativity are significant, our GPS systems would be terribly inaccurate if the engineers didn't take into account the effects of relativity.
I hope this helps, I've never tried to explain this stuff to people before.
when you travel the speed of light you actually feel no time compared to everyone else
Just to be clear, its not just feel. Its actually experience. Physically, less time passes for you.