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No Time Travel, Sorry
MOBE2001 writes "The bad news is that time does not change. Spatial velocity is given as dx/dt. Velocity in time(dt/dt) is nonsensical. As simple as that. In other words, no time travel to the past or the future, no motion in space-time, no wormholes and no hanky-panky with your great, great grandmother. There is only the changing present, aka the NOW. The good news is that distance is an illusion and we'll be able to travel instantly from anywhere to anywhere."
How else could people post articles in The Mysterious Future?
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That's weird because I could have sworn when I went to bed last night it was yesterday and now its today.
Nevertheless...this is fun. Looking at the equation from which all his arguments flow, it seems he is only demonstrating that it doesn't make sense to talk about one's velocity through time. I would agree. If I hop in my time machine and zip off to tomorrow, it doesn't make much sense for you to ask how long it took to get there. Or if you and I both have time machines and we decided to race to 1:00 pm tomorrow it would be always be a tie. But this is a far stretch from demonstrating that it is impossible. By this same logic we could define slope as the change in x over y or s = dx/dy. Does this definition make it impossible to move along the y axis because then the slope of our movement would be dy/dy? No. but it does say that if you move along the y axis your slope will be a constant.
But in all my readings, I have learned one thing about physics. Nothing is "as simple as that".
--dave
davecb@spamcop.net
This guy is a pseudo-scientific moonbat. Please don't waste your time with the not-so-FA.
Helium balloons want to be free.
As Ford Prefect put it, "Time is an illusion, lunchtime doubly so."
This sig, aah-ah, is comin' like a ghost-sig...
I'm sorry, but if you're going to put up a web page in which you call all the foremost theoretical physicsts in the world frauds, then you'd better have more evidence than some undergraduate-level pseudo-calculus and verbal smoke screens.
The t-axis or time-axis velocity component is 1, a dimensionless number. Now there are relativists who will insist that it is perfectly acceptable to express velocity in time with a dimensionless number but the rest of us with our head on our shoulders, know that it is not true. We know that a dimensionless number such as 1 has absolutely no meaning in as far as expressing velocity.
Not true. Normalized velocities are perfectly reasonable things to express. Mach 1.25 is a perfectly well-defined speed that does not violate any laws of physics, and what do you know--it's a dimensionless number.
I'm sorry, but this page is really quite embarassing for the author's parents and any physics teacher's they've ever had. This sort of reminds me of people that read things like A Brief History of Time, a perfectly excellent book, and then try to tell me that the physics is really great and it would be so much better unencumbered by the mathematics.
I don't think real time travel, a-la Dr. Who is physically possible. But the "arguments" on this web page don't really make sense, much less prove all those physics wrong.
Craig Steffen
Ph.D. Physics, Indiana Unversity, 2001
Craig Steffen
http://www.craigsteffen.net
HA! Take this from a person who has been in a long distance relationship... The distance is a reality, the relationship is the illusion.
We really outa get these theoretical scientist types out of a lab for a beer.
Victory is gained, not in knowing your opponents next move, but in preempting them.
That's it. I'm going to write a letter of complaint to Michael J. Fox and Christopher Lloyd to express my disgust at being deceived for the past 20 years.
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I'm from the year 3042. We have found that time travel is real, and would have discovered the time machine in 2048, but scientists were detered by this article.
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Spatial velocity is given as dx/dt. Velocity in time(dt/dt) is nonsensical.
That would be a lovely argument if changes in position were measured in velocity.
You describe spacial travel as the dx, not the dx/dt. It stands to reason that you would describe time travel with the dt, not as some rate of travel we haven't come up with yet.
Go into your closet, and bring enough food and water for 5 years.
Now wait...and eat sometimes.
5 years later, exit the closet.
You will find that time of the world has advanced from when last remembered by 5 years.
PS. don't forget to setup an auto-pay for your residential rent/payment. Otherwise your travel may be interrupted, and you will not be able to travel the full 5 years.
This guy is good, but he's not nearly as entertaining or mind-warping as the TimeCube guy. Four days in one!!!
- Give a man a fire and he's warm for a day, but set him on fire and he's warm for the rest of his life.
You forgot, "Slingshot the starship around the sun."
That works well when aliens try to talk to whales.
Everyone agrees that practical time travel is at the very least exceptionally unlikely. But whether our model of the universe excludes the posibility of time travel is another matter entirely.
Note that even if our model of the universe allows for time travel it does not mean that time travel is possible. Not least because we know that our model of the universe cannot possibly be completely right. Quantum physics provides an excelent model of the universe at a large scale, relativity provides a good model at the cosmological scale. The problem is that the two models are incompatible. At leas one of our models must be wrong. Most likely they are both approximations.
The other issue that the writer does not seem to grasp is that the ability for matter to travel through time and the ability of information to travel through time are very different issues. For meaningful time travel it has to be possible for information to move backwards in time and not just matter. Otherwise what would come out the other end would be a random soup of quantum particles, not the time traveller. This is the problem with black hole time travel, the most that can come out the other side is a random soup.
The 'proof' provided by the author only demonstrates that he does not have the slightest understanding of the subject he is pontificating on. dt/dt = 0??? No, all that shows is that the dimensions of the two quantities are the same. Besides x/x = 1 in most algebras.
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If "time travel" just means the usual physics definition of "tracing a trajectory backward" then of course you can regard it as happening all the time. Positrons (anti-electrons) can easily be regarded as electrons traveling "backwards" in time, so that a positron-electron annihilation event is nothing more than an electron traveling "forward" in time, then reversing itself and traveling "backward" in time. Obviously we (traveling steadily forward in time) see two particles with opposite properties converge and disappear. Whoopee.
However, I think what most people mean by "time travel" is something different, a causality loop. That is, they mean you do something (which they call "time travel") and this something lets you become your own grandpa, or influence the outcome of the Civil War, and so forth. Since, of course, those things influence the you that's influencing them (otherwise the story is not interesting), this makes a nice little loop of cause and effect: you influence x which influences you who influences x, and around and around.
Whether or not the physics of the universe allows such a thing, I can't see any obvious reason why it would cause big problems -- or even be interesting. Certainly it could not manifest itself the way it's shown in the movies, in which you see the loop first one way (Marty McFly's parents marry and produce him), and then another way (Marty's parents fail to marry, because McFly travels back in time and interferes with their meeting). That's logically impossible. If the loop exists at all, it must have one unchanging form.
That is, if Marty McFly does go "back in time" he obviously can't (or rather doesn't) prevent his parents from marrying and having him, because they actually did. Whatever he does "back in time" is already part of history. His "changes" already exist, and have always existed. Indeed, they can't even logically be regarded as "changes" because nothing really changed. Although...it's possible McFly, with his imperfect knowledge of the past, could have assumed something about the past was different than it actually was (e.g. he thought his parents met at the dance, instead of afterward, when some strangely-dressed clown introduced them). Therefore, when he "changes" history (by interfering with his parents meeting during the dance, and then "fixing" things up by introducing them afterward), he might be under the illusion that he is really "changing" history instead of simply causing it to happen as it actually did.
I suppose we could now argue about whether Marty's sense of free will (as well as our own) is therefore just a big fat self-delusion, but, ugh, not before a pint or two.
No. You misunderstand the twin paradox: the twin that journeys will age less than the twin that stays behind in the classic "paradox".
The two frames are not inertial frames since one twin accelerates during the experiment. While the result is no doubt peculiar, there actually is no paradox to resolve.
You can read all about it here:
http://en.wikipedia.org/wiki/Twin_paradox
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I just flip the page. Same with Newsweek.
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