No, I do not think that time travel is possible. I think it may be possible to slow time, but not reverse it. Though, I think something like in Paycheck with Ben Afleck, Paul Giamatti, and Aaron Eckhart is totally possible

I don't think about it much to be honest, if it comes along and scientist actually somhow gain access to it. Well thats cool, but I would not be able to use it in my lifetime

what happened in paycheck?

Theoreticly it is possible but you would not be able to go back past the date that the machine was created

I personally believe time is just something we made up to mark the rising and setting of the sun. In reality it just keeps track of the repititions of an on-going process. We could do the exact same with anything constant. Let's take a guiser for example. We may find that it blows in same intervals. From this we could say every time we see a spray, it's been a...spray-day.

Again, time is a man-made invention that does nothing more than keep track of how many times an event occurs in an on-going process.

To reverse "time" would mean to make every atom---every piece of existance---move in reverse. Which would require an immense amount of energy (more energy than exists in the universe).




Last Edit: Jan 24, 2007 23:09:56 GMT by Aaron

I guess it's possible. It would also be pretty harmless, I guess. After all, if you did go back in time to.. oh let's say today, you already did it, right? Since the past has already happened, nothing can be done to change it. Everything has already been done up to this point.

This is one of those things that I don't like to think about (like what's at the end of the universe)

I don't really think its possible because you'd have to, like Aaron said, put everything in reverse, which... i personally don't think is possible because it might not happen exactly the way it did before cause everyone might make a different decision.

Well, going into the fourth dimension is irrelative, mainly due to the fact that you would have no clue what would become of you during time travel. You may lose a part of your body, die, or be transported to another dimension as a semi-molecular atomic structure for all anyone cares. In addition, going faster than the speed of light would make you burn up, and it's be theorized by Einstein quite flatly that it's not even possible to go anywhere never 60% the speed of light, forget passing it.

However, if, say, there was "magic" and it was possible to go back in time, I certainly don't believe that you would have to revert all of space, but rather a certain area of 3rd dimensional(the area where you want to revert time) volume, which I would have absolutely no clue would look like in the 4th dimension.

Scorpion: Actually, it would be harmful. If you were to go back in time, you certainly would certainly have duplicate form of you, but that duplicate would be in a parallel universe compared to you. So, in your dimension, there would only be one of you.

Stephen Hawking's Chronology Protection Conjecture suggests that the fundamental laws of nature prevent time travel. However, in 1996 Li-Xin Li said "In the appearance of absorption material, the quantum vacuum fluctuations of all kinds of fields may be smoothed out and the spacetime with time machine may be stable against vacuum fluctuations. The chronology protection conjecture might break down, and the anti-chronology protection conjecture might hold: There is no law of physics preventing the appearance of closed timelike curves."

Backwards time-travel is possible theoretically in either of the following ways:

1. Travel at super-light speeds: Matter traveling at super-light speeds violates causality in every inertial frame of reference as explained by the concept of special relativity. Infinite energy is required to accelerate normal matter to super-light speeds - although the existence of tachyons has been theorized. These are sub-atomic particles traveling at super-light speeds.

2. Wormholes:


The Klingon God is correct.

Time dilation is the phenomenon whereby an observer finds that another's clock which is physically identical to their own is ticking at a slower rate as measured by their own clock. This is often taken to mean that time has "slowed down" for the other clock, but that is only true in the context of the observer's frame of reference. In SPECIAL RELATIVITY, the time dilation effect is reciprocal between two frames of reference. However, in GENERAL RELATIVITY, Gravitational Time Dilation is not reciprocal - clocks in proximity to strong gravitational fields run slower - this is true in all frames of reference. Thus if a wormhole is created by warping space/time between two points, with one end accelerated way more than the other, and thus time moving slower (relative to the person entering from the accelerated end) at the end with lower acceleration. Thus time will appear to move in reverse and as temporal travel backwards in the continuum is possible. One significant limitation of such a time machine is that it is only possible to go as far back in time as the initial creation of the machine.

Scientists talk of the Twin Paradox as given by Paul Langevin in 1911. If a spaceship travels away from Earth at a velocity approaching the speed of light and then returns to Earth, then more time would have passed on Earth as compared to on the spaceship. If a pair of twins were born on the day the ship left, and one went on the journey while the other stayed on earth, the twins will meet again when the traveler is younger and the stay-at-home twin is older. This outcome is predicted by Einstein's special theory of relativity. It is a consequence of the experimentally verified phenomenon of time dilation, in which a moving clock is found to experience a reduced amount of proper time as determined by clocks synchronized with a stationary clock.

Then there's the Grandfather Paradox to deal with. If a person were to travel back in time and kill his own grandfather when he's a child, then the grandfather never had a son and thus there never was a grandchild and so nobody is traveling back in the first place. Its a causality loop. However, according to the current Multiverse theories, if a person did actually go back in time and kill his grandfather, then that decision would cause the timeline to split into 2: the normal timeline and the one as described by the grandfather paradox above.

General relativity describes the universe under a system of field equations, and there exist solutions to these equations that permit what are called "closed time-like curves," and hence time travel into the past. The first of these was proposed by Kurt Gödel, a solution known as the Gödel metric. Whether general relativity forbids closed time-like curves for all realistic conditions is unknown.

In Quantum Physics, the Casimir effect is a physical force exerted between separate objects, which is due to neither charge, gravity, nor the exchange of particles, but instead is due to resonance of all-pervasive energy fields in the intervening space between the objects. This effect could allow the creation of traversable wormholes using exotic matter with minimum negative energy.

3. Cosmic Strings and Black Holes

An observer might take a trip away from the Earth and back at relativistic velocities, with the trip only lasting a few years according to the observer's own clocks, and return to find that thousands of years had passed on Earth. Thus, in essence he's traveled to the future - as shown in PLANET OF THE APES.

Traveling to the future again requires use of event horizons and super-light speed travel.

Zero-point energy, as in energy in vacuum states, could be utilized for time-travel. Rotating electromagnetic fields and Quantum entanglement are areas being researched on.

Aside from all this, several other concepts, theories and paradoxes are possible. As of this point, there is not scientific evidence for showing that time-travel (either backwards or forwards) is actually possible.

I was gonna say something to what Aaron said as to how we have stuff like clocks to measure the immeasurable, but you guys did that and then some.

I bet some of us on this forum would be either really old and grey or dead by the time scientist make it safe for the genral public

en.wikipedia.org/wiki/Paycheck_%28movie%29


Basically, time travel=no go. Time viewing=the real future