Feasability of time travel

Here's something I posted on another site to see what kind of comments I get but I think the people here would be more nerdy for this kind of thing so here goes:

I came up with this the other day. Feel free to repost or send it on.

In reference to time travel we have all heard to the grandfather paradox. Now let me throw you a new curve. When we see time travel in movies the person simply goes through time instantly but remains in the same place? Well when they wrote the script they forgot about something. That same spot in space will not be the same spot on Earth in whatever time they went to. The Earth revolves on its axis so the spot on Earth where you are is constantly moving through space and in turn the Earth orbits the sun at a speed of 66,600 miles per hour (18.5 miles per second or 29.8 kilometers per second). If you were to go back in time just one second remember that even though you materialize in the same place the Earth has moved 18.5 miles. You would end up 18.5 miles above the Earth and fall to your death or be 18.5 miles underground in solid rock or somewhere in between. If you went forward or back a few months you would materialize in empty space at the place where the Earth was a few months ago in its orbit. Ahh, but wait. Its worse that that. Not only is the Earth orbiting the Sun but our Sun orbits the core of the galaxy at a speed of 450,000 miles per hour (125 miles per second) so even if you calculated your jump so that the Earth would be at the same place in its orbit to the fraction of an inch remember that the entire solar system has moved around the galactic core. How would you calculate that? It wont return to that spot for millions of years and then tiny eccentricities in that orbit caused by the gravitational pull of other moving bodies in the galaxy dictate that it will never be in exactly the same spot again. Oops, wait a minute. It wont ever be at that spot again. There's more to consider. Our galaxy is moving through space as well as the universe expands. That means that the spot on which you are standing on Earth at any given instant will never be at the same fixed place in space again ever. Your time machine would have to be able to not only travel through time but space as well. Before you hit the big red button you would have to calculate the exact point in space where the spot on Earth that is your destination will be at the time to which you are going and it will have to be accurate to a very tiny fraction of a second. Your exit velocity will have to be equal to the resultant vector of the Earth's rotational direction and velocity, its orbital direction and velocity, the sun's orbital direction and velocity around the galactic core, and the galaxy's direction and velocity with respect to a given fixed point in space. You would also have to factor in the effects of the gravitational pull of all other celestial bodies that will come with x number of light years of our sun during its orbit around the galactic core and you would have to know their direction and velocity to accurately make those calculations. Now remember that all the bodies mentioned follow curved or elliptical paths not straight lines so their exact curved paths, mass (to calculate gravity), and speed all need to be known not just as one instant but for the entire time period which you will be travelling across. The further you go forward or back in time the longer of a distance all these bodies will have moved and you need to be able to account for all of their positions for the entire time period. Then there is the factor of all the astronomical bodies whose gravitation will in turn have an effect on the ones you just calculated for. How much is the space-time continuum warped by the gravitational fields of all those objects and how much does their gravitational pulls effect he path of our sun and thus the Earth as it moves through space? The amount of data and the precise calculations required are astounding even if you are only to go a few days forward or back. If you go years through time then any small error in your calculations will be multiplied exponentially and you will end up in empty space or in solid rock or in magma inside the Earth. Then there is dark matter. We cannot see it but its mass creates a gravitational field that will also have an effect on the ever wandering Earth. Since we cannot see dark matter it's effect would be a missing variable in our equation which would throw off our exit location when we emerged at our destination time. Is time travel possible? We may never know if it is possible but is it practical or feasible? Certainly not. It it were possible to move from one moment in time to a much earlier or later time you will find that the Earth has moved very far away from you position and it would be an impossible task to calculate where your exact current location on the surface of the Earth will be at a given instant in the past or future. Even the best astronomers on Earth can only give a range of distances that vary by several thousand miles on how close a comet or meteoroid or comet will come on its closest approach to Earth as it passes nearby.

Hey wait a minute. Come to think of it Mr. Jones next door came back from the hardware store with an item he needed to finish a project. The box he was holding said "flux capacitor." He went into the garage and I heard him tinkering for a while then I never saw him again. It's been 15 years. Hmmmm.

Most of the theory suggests even if time travel is possible, it will require extreme velocities well beyond the speed of light. In that case, you would be in a space ship, so none of what you mentioned would be applicable. Also, assuming someone invents a time machine which will work when stationary, I'm not 100% sure anything you mentioned would be an issue. After all, we're all moving forward in time just fine without ending up in space. I would imagine going the other way would be no different. We would still be stuck in the Earth's gravity well, so we would end up where it was, rather than at some arbitrary point in space.

Of course, assuming you're right, it would be difficult for anyone to design a working time machine. The prototypes would all disappear to some arbitrary point in space never to return the second you turned them on.

Time travel wouldn't work if time inherently follows your logical conclusion, the idea of absolute position. I think it has something to do with human ignorance and arrogance that mist if us assume that if we time travel we will end up exactly where we travelled from, but in a different time. Perhaps time follows some sort of relative positioning based on gravitational or other attractive forces. Time travel is impossible unless you can access a dimension at least one order above ours...even the development would require some feedback from where ever and whenever the subject arrives. We would need some naturally occcuring or preexisting phenomenon to observe as we cannot open the fourth dimension.

That new sidewalk was a chunk of wet concrete 20 years ago. Congrats!.... Now you're up to your ankles in wet concrete.

Even worse?.... That open parking lot was a crowded basment full of pillars and heavy equipment 20 years ago. Travel back in time, and now you materialize inside a concrete pillar that wasn't there in the spot you were standing at, 20 years ago.

Working on a time-travel novel. Bouncing around in my head for a few years. Basically, government run. Official agent time travelers travel from time to time thanks to buildings preserved as historical sites. 20 years ago, that open room in the historical, colonial house was an open room. Problem solved!

Is that why when I tour those old buildings and our tour group moves to another room there is person in the group that I could swear was not there in the previous room? :thinking:

Tim B said:

Is that why when I tour those old buildings and our tour group moves to another room there is person in the group that I could swear was not there in the previous room? :thinking:

Click to expand...

Could be.....

Is like, when you go somewhere, you travel in time a little slower, kinda. But when you go back to verify time using your originating point in space/time, you or informations travel in time a little more quickly, and it all kinda balances out.

It's almost like when you pick one point in space/time to be your frame of reference, effects of time acts like a field radiating outward from that point.

Personally, I don't believe in time. Time's just a concept we use to understand in our minds how things "were" and how they "will be." Like that one, kinda after-thought-ish, line from the Matrix, your mind makes it real.

Whoa, I know Kung Fu...

Time travel, in the way its typically meant, such as for time travel in movies, etc, can not happen.

Time is a construct, and, while you can see that corrections for a GPS, etc, are needed when the satellites are in geosynchronous orbits, etc, in confirmation of relativity etc, it doesn't mean that there is a past waiting for you to go back to it.

IE: It already happened, and will not "happen again so you can watch".

So, you can essentially change what time it is...but not make a historical event reoccur.

You can for example see or hear an event that occurred some time ago, because it took the light or sound, etc, from it a long time to get to you - but its not "Happening again", you are simply receiving the evidence of it after the fact.



So, forgetting all the paradoxes that people come up with, like what if you murdered your parents before you were born, etc...these are pointless without a true context.


Think of it this way...if you were going to travel back in time to kill your parents, say in 1950, before you were born....and its now 2014....you already DID it, because, you had to have DONE IT back in 1950....so, its already happened.

As you would not have been born, you could not go back in time...and, therefore, you would not have killed your parents. So every thing stays the same as the present, no matter when the present is.

You were correct in picking this forum for your time travel debate,my anorak is on and popcorn at hand to read the posts.

I figured it out over a weekend last month:

StarHalo said:

When you have a timeline wherein time travel is introduced/invented, paradoxes mean loops that extinguish themselves, i.e. the guy who goes back and kills his grandfather ceases to exist. This means that anyone within time-travel-exists timeline (which could be a few weeks or a few billion years, so it would be many billions of people or generations more) need only come to the conclusion "we would have been better off without time travel," and that person goes back and kills the inventor/destroys the plans/etc. and then that entire timeline becomes a loop and extinguishes - it only takes that one person, and over a long enough timeline [and we're literally working with timelines] someone will eventually do it. So only the core timeline where time travel is never invented continues.


Therefore the existence of time travel ensures that time travel will never exist.

Click to expand...

Time is not a slave to your rules of logic.

In my mind, a time machine cannot be a vessel to travel in because time is not a destination. A true time machine would have to reconfigure every piece of matter in the universe to it's exact state at the desired "time." Including the matter that makes up you and the machine. Just my 2 cents.

Oh and if anyone watches anime, Steins Gate is a super good one based on time travel and time paradox (a world dominated by SERN) xD

Id imagine time travel to be like travelling from one destination to another. But with more co-ordinates than just latitude and longditude. But also a chronological destination. Which would mean you pre program your position geographically and chronologically, thus being able to predict where you will arrive.

AmperSand said:

Id imagine time travel to be like travelling from one destination to another. But with more co-ordinates than just latitude and longditude. But also a chronological destination. Which would mean you pre program your position geographically and chronologically, thus being able to predict where you will arrive.

Click to expand...

That presumes that the "points" in time you are moving between somehow all exist independently rather than being different points on the trajectory of the universe through space and time. That is the problem that Mashadaar posed.

inetdog said:

That presumes that the "points" in time you are moving between somehow all exist independently rather than being different points on the trajectory of the universe through space and time. That is the problem that Mashadaar posed.

Click to expand...

Yes, that is correct! Thank you for explaining it so clearly!

Just a whimsical pipe dream. But I'd like to go back and see all of my long past relatives that led to me being here. What they were like and what they did.

Alright I've been wanting to ask sum one about time travel for awhile now.
So has anyone seen the movie 'Deja vu' with Denzel Washington? So a big part of that story was based on time travel. Well I was wondering what theory were they basing there concept on. Or what would've had to be true/real to make that whole story work? And at the end of the movie it seemed like they were using a couple different time travel theory's.

I just thought I'd throw that out there. I liked the movie and the whole idea of time travel is super fascinating to me. And I'd really like to hear what someone else had to say on the matter.

You are all forgetting that there are multiple universes to consider!

In an earlier thread I explained about the multiple universes interpretation of quantum mechanics in case you need a refresher.

With multiple universes, there are no time inconsistencies or paradoxes or loops.

So you go back in time to kill your own grandfather (why you would want to do kill your own grandfather, is what never made sense to me, but let's proceed).

And you succeed, but are still around. How?

Obviously, you jumped to another identical universe, killed your other self's grandfather, thus destroying all of his descendants, which of course do not include you!

What about the "positioning" problems in the OP's post?

Again, no problem. Time jumps are possible between adjacent parallel universes. There is some kind of link, and you can time jump only because the link exists. So you get to the time and "place" you are aiming at instead of some random void, because without the link you couldn't get anywhere.

Any more questions

Multiple universes is still just a theory. All we can verify is that this one exists.

flashy bazook said:

You are all forgetting that there are multiple universes to consider!

In an earlier thread I explained about the multiple universes interpretation of quantum mechanics in case you need a refresher.

With multiple universes, there are no time inconsistencies or paradoxes or loops.

So you go back in time to kill your own grandfather (why you would want to do kill your own grandfather, is what never made sense to me, but let's proceed).

And you succeed, but are still around. How?

Obviously, you jumped to another identical universe, killed your other self's grandfather, thus destroying all of his descendants, which of course do not include you!

What about the "positioning" problems in the OP's post?

Again, no problem. Time jumps are possible between adjacent parallel universes. There is some kind of link, and you can time jump only because the link exists. So you get to the time and "place" you are aiming at instead of some random void, because without the link you couldn't get anywhere.

Any more questions

Click to expand...

It still doesn't work, because any time travel that will occur int he future has already happened, so things will be the same as the present.

IE: You will never go back in time to kill your grandfather because if you did, you had already done it back when he was alive. Remember, if you are going back in time, you already did it and the results are "your present".



If you are not a decedent, than he is not a relative, and was not your grandfather....and you have simply murdered some stranger in another dimension....but, again, if you were going to go back an murder the poor guy, he died back then already...so, it already happened....and hes not there, now, to go back in time to kill.