We are all time travelers, but is "time travel" is a silly idea? IMO we are just moving to fast. The net is about 1M/ mph toward the constellation Leo, but there are all the other rotations to account for to. So you want to go back in time 10 days - that's 240M miles, and sorry there's nothing there right now. Forward seems OK, but you better be fast and navigate really well unless you want to live in empty space and many other problems, e.g., how to slow down, fuel, not running into things you don't know about. There's the worm hole thing, but I think I read that would take more energy than just normal travel to create. Who has the answer?
Maybe bend bend time and space .... Survive a black hole ... You should be Ok after that .
What about other dimensions? I saw a video a few years back that showed a wavy figure, no clear form, "ghost" if you like, that set off an alarm in a Habitat for Humanity in North Carolina. I'll see if I can post that video link and a note about it in a discussion. Food for thought.
I don't know. Everything we know is height, depth, width, and time. I imagine if there are other dimensions they would be traveling in the same space as we are. A multiverse might have different rules than this one, but I think it would take traveling through a black hole to find out.
I personally do not believe in time. OK I set appointments etc, to fit in with everybody else. To me time is a man made concept to understand mass, motion, force, acceleration and other physical forces. I really like your explanation of the difficulties. Given the speed of the earth, if I went back in time 5 minutes, it wouldn't be here and I would be stranded in the cold void in space. The concept of time allows us to put things in order, beginning middle end. We use time to help us understand that every element in the universe was once there, but now it is here. To go back in time if there was such a thing, the energy required would need to be enough to arrest all current movement of matter and energy and then push it back to where it was at the time you wish to go back to. If we could view our reality from a perspective outside of it, say and additional physical dimension, or perhaps 2 additional physical dimensions would could perhaps observes what we consider past present and future simultaneously. Yes I am crazy, so to prove it (that I am crazy) , our subconscious mind (s) do not operate in time as we understand it. A dream lasting a microsecond, can be a story of hours, another dream of seconds may occur in our mind over a longer period. Similarly as we age, each year seems to pass more quickly. This is because of how our brains store information.
I do not think that time travel is possible -- at all. But, even if it were, all it would do is to create never-ending historical chaos. If we were able to go back in time, all that we would inevitably alter that past in some way, large or small. The ling term effects of even the smallest change in a massive scaled system are totally unpredictable. If we were , then, able to return to the present, it would be very different from the place we knew.
The problems of time travel are many. As you stated there is the problem of space. We are traveling on a planet that is rotating whiel orbiting out sun, which is an a solar system, which is in a galaxy that is also revolving, and the galaxy is hurtling through space at an even increasing speed. So, you may be able to travel in time, but unless you also traveled through space and got allt he calculations just right you'd most likely end up in enpty space. Which I beliee is the point you raised above.
There is yet another problem. As matter gets close to the speed of light, mass increases, and it is unknown if a life form can survive this. So, this compounds the space probem above even more. If you wante dto travel through a significant amoutn of time, you woudl need near light speeds and experience increased mass, if you wanted to come out on oru own planet.
Add in gravity. Gravitational influence make ever so slight changes in the way our planet and galaxy moves. Over short times it may not be that significant, but over long periods of time, those small differences add up to great distances. How does one add in those influences in calculaions when they are not really known?
So, I can confidently say that time travel will ntohappen in our life times.
Of course there is also the paradox problems. Assuming time travel were possible, you could go back in time and kill one of your own ancestors, but in a multiverse, you would have just created an alternate universe in which you would never have been born. Assuming you could travel back to your universe of origin, you would fidn that nothing really changed in your own universe.
Personally, i find it highly doubtful that a person who traveled to an alternate universe would be able to get back to their own universe. I am agnostic about the idea of other worldly aliens, visiting our planet, but I think if they did, it would be more likely they are from alternate universes, and the equivalent of our own planet in that universe, than from a distant part of our own galaxy, as the incease in mass near light speed would make it difficult for any bio0logical entity to survive.
The only exception (that I am aware of) would be if one discovered how to "fold" space as a means of travel. I am dubious though that space cn be folded seamlessly in such a way that would not endanger the lif eof biological organisms such as ourselves.
You comments on mass and speed reminded me about a book by Poul Anderson called Tau Zero. Not to give away the story, but some people head to a new planet got going so fast they couldn't stop and other things - very nicely done. It would make a good movie.
I have often thought about how the earth (and our solar system) is drifting through space and to travel back in time one would have to rendezvous with earth back in the time and PLACE where it was as noted by the original poster. A quandary of equal proportions is if time travel were to become possible, should anyone be allowed to go back in time...consider that the mere presence of a person from the future would almost certainly change the future from that point on. Also, consider the temptation to change history. Think of Hitler being assassinated by a time traveler...millions of people would continue to exist and reproduce and therefore change our present unmeasurably and likely not for the good. We cannot develop time travel even if it is possible...we cannot risk it.
Are you talking about moving at relativistic speeds to "leapfrog" forwards in Earth relative time, or something else?
As I understand it, relativity means time can be experienced differently at different velocities. Time will pass more slowly for one the faster you go.
@jeffy yes, relative to someone not going as fast. The phenomenon is called time dilation. So you could fly around really fast for a while then come back to earth where more time would have passed, and you'd feel like you'd traveled into the future.
The problem is that you need to be closer to the speed of light than we are currently capable of travelling for it to really make a noticeable difference. It only works if you want to "go forwards" in time though. It also only works for conventional A-B travel, where the moving object accelerates to the speed it travels at. Exotic hypothetical forms of travel like Alcubierre drives wouldn't necessarily cause time dilation because they manipulate space in order to move.