European Union Forums

[Eddie]

In a question, someone answered that if we were able to travel the speed of light, then we could somehow achieve time travel. How would this happen?

Also, how could we make time travel possible? Is there some formula to it? I think time travel is a really awesome concept, and I want to learn more about it.

[MichaelWRuiz]

Well here's a problem with time travel. The Earth is revolving around the sun at thousands of miles an hour. If you were to travel in time, you'd be out in space and the Earth would be far away.

The Earth is also rotating at around a thousand miles per hour.

The Sun and all of its planets together are revolving around the center of our galaxy, about once per 200 million years and moving fast.

The galaxy is also moving toward the "great attractor".

[Lisa.D.Hicks]

If one was to travel at the speed of light through space then return to earth, the traveler would age less then the people on earth. Less time would pass. Hence time travel.

[Dirk]

Let's say you wanted to kill yourself in a funny way. You got a knife to stab yourself with. Then you went to a long street and instantly teleported yourself to the other end, many miles away. You quickly turn around and see the light from your earlier self catching up with you. Then you instantly teleport yourself back to where you were before. You see yourself before you teleported the first time! Quickly, you stab this earlier version of you to death. Since you died before you could teleport the first time, how could you have lived long enough to stab yourself? It's stuff like that that makes people doubt that time travel, or travelling faster than the speed of light, will ever be possible. (Not to mention the fact that an infinite amount of energy must be spent to accelerate to the speed of light.)

Also, if you had a gun that could shoot bullets faster than the speed of light, you might get killed by a ricochet bullet before you ever pulled the trigger.

[NancyKLynch]

Hi. Time is one of 4 commonly understood dimensions. (X,Y, and Z are the others.) The rate at which time seems to advance seems to slow down for an object as it approaches the speed of light (known as 'c'). If you were traveling at a speed close to light 'your' time would seem to go by as normal to you while 'our' time would pass at 'normal' speed for us. This is not a theory. It has been proven. So, in a way, you would seem to be traveling into the future. If you could somehow stop and return here many years would have gone by and you would be in the future.

[Elbert]

Space-Time, Entropy, and the Arrow of Time
In 1905, Albert Einstein proposed a theory that unified mass, energy, motion through space, the relativity of time, and formed a new mathematical concept called spacetime. All objects in the universe move through spacial dimensions while time passes, but the rate at which time passes is relative to the velocity that you are traveling. We humans experience three dimensions on a daily basis (our frame of reference), and within our frame of reference, time "flows" at a rate of 1 second per second. Observers from a different frame of reference will see our frame moving faster or slower than theirs, but they will still measure time in their frame at 1 second per second.

Some physicists have hypothesized that the reason time "flows" is because of a property of matter called entropy defined in the Second Law of Thermodynamics. Entropy is the measurement of how energy will disperse in a given system, such that energy will always move from a higher state to a lower equilibrium state. It is proposed that the entire universe is "unwinding" from its initial high energy state (the "Big Bang") creating the dimension of "time" as the universe expands.

In physics, the mathematics behind the known laws of space-time are symmetric; in other words, the formulas are the same for an object moving forward in the time as an object moving backwards in time. Knowing an object's current position and velocity lets you determine where an object was (backwards in time) and where an object is going (forwards in time).

However, we humans do not perceive time flowing in both directions. For us, the arrow of time points "forward". We have a memory of where we have been, but no perception of what we are going to do; we can only perceive the probability of events that will occur as derived from our current conditions.

Cause and Effect
In the direction of forward flowing time, an action (cause) will have a predictable outcome (effect) according to the laws of physics, where the cause always precedes effect.

Paradox
If alteration of a sequence of events (via time travel) were to occur where an effect no longer had a cause, the situation would result in a paradox. Perhaps the most common thought experiment is the grandfather paradox, where a time traveler goes back in time and inadvertently causes the death of his own grandfather (effect) before his father's conception. If his father were never born, then the traveler himself would never be born, and thus he could never go back in time, and thus never cause the death of his grandparent. If the grandfather is not dead, then he has a child, who has a child who becomes the time travele

[Elbert]

As far as I can see, no one has managed to answer your question correctly.

Firstly - it is NOT POSSIBLE to travel at the speed of light, or faster than it. NEVER, NEVER, NEVER. Therefore wondering what would happen if we did is pointless.

However, as Einstein showed, weird, weird things start to happen the faster we go - most notably time dilation. At speeds approaching those of light, any travellers time would slow down relative to anyone who happened to be observing them.

Therefore, theoretically, we could potentially time travel if we could manage to travel at a speed close to light - but this is certainly not possible with today's technology.

This only relates to time travel into the future, btw - there's no current theory on how travel into the past could be achieved.

[Andrew.A.Roy]

If you want to break one Law of Physics, why not break them all?
Lets have talking white rabbits, dragons, ghosts, faeries and space aliens. Why not? Lets break the rules of cause and effect.
The Science is very stark: it says it is impossible for ordinary matter to attain light speed.
The meta-science says that Science is a work in progress and that nothing is ever beyond reinterpretation and modification as new facts come into play. What we know is that if we are right then it can't happen, we do not know we are right beyond all possible doubt. Pragmatically however, the difference between where we are now and "absolutely 100% sure" is pretty small and not worth
distinguishing between. Except for entertainment and fantasy escape.
So, tell me: of all the things you know are true, which aren't?
Kinda silly when put that way, huh? cuz' if we knew then ...
So many (too many) that ask questions here seem to be unaware that if we assume something known to be false is true, then we can prove anything false or true. These "what if" questions often start with a false premise. There is no rational argument that can take us from that point to anything useful, except as fantasy.

[Joanne.A.Brewer]

First of all, Traveling the speed of light is IMPOSSIBLE! But if you want to ask me a "what if..." question, here's the answer: If you could travel the speed of light, you would travel faster than time itself, thus leading to time travel.

Now, the easiest way to achieve time travel, (which I still think is impossible) you will need the following items:
-Black hole
-Large, powerful spacecraft with "return ship."
-A pilot crazy enough to attempt this
Step 1: According to Einstein, a black hole has two ends, therefore the pilot must get one end to follow the back of the ship, and twist it around the other end.
Step 2: The pilot must now enter the black hole.
Step 3: Watch the pilot scream his little voice out as he starts his terrifying journey to the future.
Step 4: Wait about 50 years for his return
Step 5: Watch as the pilot zooms through the atmosphere in the "return ship."
Step 6: Stare in amazement as the pilot comes out unharmed, looking as young as he was 50 years ago.
Step 7: Give the pilot a pat on the back for breaking one of the laws of physics.

[ThomasVRose]

I feel that time is just another form of energy which is a leak from what i would like to call the mEnergy/empty space, we have acquired the art of trapping/routing/transforming energy fields like gravitation, electrostatic, magnetic, etc which are also a byproduct of the mEnergy/empty space. We are yet to understand/accept the fact that time is energy and can be trapped/routed/transformed in the near future, it can evolve to be disastrous or the fact that we are "lost in time" as our brains are not capable to handle it between different worlds/time. The reason WHY GOD is SO DARK as no one has seen. I go nuts whenever i think about time....................................

[DavidDPowers]

SpaceTime is the 4th Dimension
The faster you travel through it the faster time passes by.
Curving spacetime causes time to slow down
Earths mass effecting spacetime causing a curve
http://upload.wikimedia.org/wikipedia/c ... vature.png
But in reality it is 4D so the curve is more like this:
http://img506.imageshack.us/img506/5015 ... imelu3.jpg

The time in empty space travels faster than time on Earth due to Earth causing a curve in spacetime

Its like this the curve means more space for something to travel across ie time where as a smooth spacetime takes less space for something to travel across like someone running across a valley while another runs across a flat surface.
Traveling faster is like running faster than someone else you will get to the finish line before them ie travel faster in space youll be in the future before the time you would if you went slower.

[DavidSGordon]

we could achieve time travel

[Dexter]

No, because God created time and only He can control time (and also space). If a man can travel through time, he is te most powerful man, coz if he made a mistake he can go back and change his mistake easily. Well, you can only travel through time forward but you can't skip a second, you still have to wait every second.
Time travel-impossible