Time Travel Impossible According to Physicists

CommanderFrank

CommanderFrank

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Scientists in Hong Kong have reported that after conducting tests attempting to accelerate a single photon particle past the speed of light, that Einstein’s ‘traffic law’ of light speed has been confirmed: Nothing can go faster than the speed of light. They also confirmed that the Earth was indeed flat, but needed additional research :D

"The study, which showed that single photons also obey the speed limit, confirms Einstein's causality; that is, an effect cannot occur before its cause,"
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MajorDomo said:
Scientists in Hong Kong have reported that after conducting tests attempting to accelerate a single photon particle past the speed of light, that Einstein’s ‘traffic law’ of light speed has been confirmed: Nothing can go faster than the speed of light. They also confirmed that the Earth was indeed flat, but needed additional research :D
Click to expand...

Heh :D I guess they missed this wiki:
Faster-than-light travel
The impossibility of faster-than-light relative speed only applies locally. Wormholes allow superluminal (faster-than-light) travel by ensuring that the speed of light is not exceeded locally at any time. While traveling through a wormhole, subluminal (slower-than-light) speeds are used. If two points are connected by a wormhole, the time taken to traverse it would be less than the time it would take a light beam to make the journey if it took a path through the space outside the wormhole. However, a light beam traveling through the wormhole would always beat the traveler. As an analogy, running around to the opposite side of a mountain at maximum speed may take longer than walking through a tunnel crossing it.

[ame="http://en.wikipedia.org/wiki/Wormhole"]Wormhole - Wikipedia, the free encyclopedia@@AMEPARAM@@/wiki/File:LorentzianWormhole.jpg" class="image"><img alt="" src="http://upload.wikimedia.org/wikipedia/commons/thumb/d/d7/LorentzianWormhole.jpg/220px-LorentzianWormhole.jpg"@@AMEPARAM@@commons/thumb/d/d7/LorentzianWormhole.jpg/220px-LorentzianWormhole.jpg[/ame]
 
Has the past already been changed, by the future, and not
in the present?...:confused:
 
They also know that science isn't religion? Rules are only there until they are disproved and the next theory comes along that is more correct. Just because it came from the divine saint einstein doesn't mean it's infallable.
 
<sits in armchair>

Well gee who would have thought that light would only travel the speed of light!!! Really is this China's contribution to the world to act like they're doing science! (ok sorry that was an unnecessary jab).

I'm curious how they thought they could accelerate said light though, you'd need to apply a force in the direction of travel, but if nothing travels faster than light nothing could catch up to it to accelerate it in the first place "Well we found your problem! You need something faster than light to push it faster than light duh!"

Why is this posted here again?
 
just make sure to code in a loop counter otherwise...
 
Am I missing something?

The impossibility of particles moving at speeds faster than the speed of light DOESN'T disprove time travel one bit. In fact, it sort of strengthen the theory..

The entire point is that BECAUSE you can't travel at the speed of light, the "universe" will slow you down if you manage to reach that speed.. and BY slowing you down, it will literally cause you to move in time, instead of space.

The CLOSER you get to the speed of light, the faster through time you can go.

As for traveling back in time, that might be impossible.
 
Trackr said:
Am I missing something?

The impossibility of particles moving at speeds faster than the speed of light DOESN'T disprove time travel one bit. In fact, it sort of strengthen the theory..

The entire point is that BECAUSE you can't travel at the speed of light, the "universe" will slow you down if you manage to reach that speed.. and BY slowing you down, it will literally cause you to move in time, instead of space.

The CLOSER you get to the speed of light, the faster through time you can go.

As for traveling back in time, that might be impossible.
Click to expand...

that is time dilation, not exactly the same thing. you still can't violate causality or travel through time.
 
Trackr said:
Am I missing something?

The impossibility of particles moving at speeds faster than the speed of light DOESN'T disprove time travel one bit. In fact, it sort of strengthen the theory..

The entire point is that BECAUSE you can't travel at the speed of light, the "universe" will slow you down if you manage to reach that speed.. and BY slowing you down, it will literally cause you to move in time, instead of space.

The CLOSER you get to the speed of light, the faster through time you can go.

As for traveling back in time, that might be impossible.
Click to expand...

If there are other dimensions, or even multi-univereses, then the time barrier
may not mean anything.

Science channel "Through the Wormhole" episode on time travel goes into
this theroy as one way to subvert it.
 
Do actions in one universe/dimension affect the other? If so, how?
 
I've always believed that time travel is indeed impossible.

Space-time travel, however, should be entirely doable if the conditions were just right... that's one of those things the Terminator movies actually got right to some degree: it wasn't just the person or the Terminator being sent back alone: it was a bubble of space-time that transposed from the future with the same amount of material from the past, so a "cosmic swap" if you will.

"Going back in time" alone would break the fundamental laws of the universe as we know it: if I suddenly went back in time 10 years from this moment as I'm typing this sentence, suddenly the universe 10 years ago becomes "The universe + me" and that just can't happen - can't create new matter out of nothing at all.

Seems pretty simple when you think about it.
 
450 said:
Do actions in one universe/dimension affect the other? If so, how?
Click to expand...

The science show gave an example of how you could kill your grandfather
and yet your alive to do it, because your were born in another dimension
of time.

Thus, they think that paradox is possible.

There repeating those shows, give it a watch.
 
450 said:
Do actions in one universe/dimension affect the other? If so, how?
Click to expand...

Probably at a much lesser degree, like people theorize gravity is much lesser than other forces because it's from a different dimention blah blah. So small youd probably not notice...

Also...if time isn't a constant (as it probably isn't) and ebbs and flows, you might be able to ride an "ebb" or "flow" for limited moves through time. Or, if there were dimentions with greater speed of time or slower or even reversed time (remember that in physics all effects can be reversed by doing the same thing backwards and time might be inverted or whatever) and so spending time in these different flowrate dimentions would have the effect of travelling through time in the standard universe.

Or you could drink meth and think you are doing it.
 
TheWeazmeister said:
Heh :D I guess they missed this wiki:
Faster-than-light travel
The impossibility of faster-than-light relative speed only applies locally. Wormholes allow superluminal (faster-than-light) travel by ensuring that the speed of light is not exceeded locally at any time. While traveling through a wormhole, subluminal (slower-than-light) speeds are used. If two points are connected by a wormhole, the time taken to traverse it would be less than the time it would take a light beam to make the journey if it took a path through the space outside the wormhole. However, a light beam traveling through the wormhole would always beat the traveler. As an analogy, running around to the opposite side of a mountain at maximum speed may take longer than walking through a tunnel crossing it.

Wormhole - Wikipedia, the free encyclopedia
Click to expand...

Good luck actually creating one that can remain stable for long enough and be large enough for a "starship" to pass through.

Exploiting Heim theory for FTL travel is much more probable than creating a stable wormhole.

[ame="http://en.wikipedia.org/wiki/Heim_theory"]Heim theory - Wikipedia, the free encyclopedia@@AMEPARAM@@/wiki/File:Wormhole_travel_as_envisioned_by_Les_Bossinas_for_NASA.jpg" class="image"><img alt="" src="http://upload.wikimedia.org/wikipedia/commons/thumb/7/70/Wormhole_travel_as_envisioned_by_Les_Bossinas_for_NASA.jpg/220px-Wormhole_travel_as_envisioned_by_Les_Bossinas_for_NASA.jpg"@@AMEPARAM@@commons/thumb/7/70/Wormhole_travel_as_envisioned_by_Les_Bossinas_for_NASA.jpg/220px-Wormhole_travel_as_envisioned_by_Les_Bossinas_for_NASA.jpg[/ame]
 
I get all my science from "The Big Bang Theory", Sheldon
has got the research!...:p
 
http://science.nasa.gov/science-news/science-at-nasa/2004/23jan_entangled/

and

[ame="http://en.wikipedia.org/wiki/Quantum_teleportation"]Quantum teleportation - Wikipedia, the free encyclopedia@@AMEPARAM@@/wiki/File:Quantum_teleportation_diagram.PNG" class="image"><img alt="" src="http://upload.wikimedia.org/wikipedia/en/thumb/8/80/Quantum_teleportation_diagram.PNG/300px-Quantum_teleportation_diagram.PNG"@@AMEPARAM@@en/thumb/8/80/Quantum_teleportation_diagram.PNG/300px-Quantum_teleportation_diagram.PNG[/ame]

So....yeah..
 
ThisIsTheNewSound said:
Pish posh, I'm traveling through time, to the future, as we speak! Anyone else wanna come along for the ride?
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Sure, but we need to make one stop:
[ame="http://www.youtube.com/watch?v=fSGQPzS0p5E"]&#x202a;Futurama Professor Farnsworth kills Hitler&#x202c;&rlm; - YouTube[/ame]
 
You've got to keep in mind that this is coming from a nation that has recently banned sci-fi media involving time travel.
 
Trackr said:
Am I missing something?

The impossibility of particles moving at speeds faster than the speed of light DOESN'T disprove time travel one bit. In fact, it sort of strengthen the theory..

The entire point is that BECAUSE you can't travel at the speed of light, the "universe" will slow you down if you manage to reach that speed.. and BY slowing you down, it will literally cause you to move in time, instead of space.

The CLOSER you get to the speed of light, the faster through time you can go.

As for traveling back in time, that might be impossible.
Click to expand...

Let's see if I can explain this. This will not be easy to understand if you don't have some basic relativity under your belt.

In a more complicated version of relativity than you'd get in an introductory college modern physics course, you would learn about 4-vectors and Lorentz invariant quantities. Lorentz invariant quantities are pretty much things that amount to the lengths of vectors in a vector space. Relativistic 4-velocities are defined in a funny way because time can no longer be used as the differentiation parameter. Time is a coordinate in a vector, w=(t,x,y,z). It is no longer a monotonically increasing number like it is in Newtonian physics, so it doesn't work for the definition of a velocity.

Instead, the differentiation that defines a 4-velocity is taken with respect to what is called proper time, ds^2=-dt^2+dx^2+dy^2+dz^2. This is essentially the length of the worldline traced out by the particle as it moves through spacetime. This quantity is monotonically increasing like it needs to be, but sadly, it gives velocity a funny property and interpretation. The Lorentz invariant formed when you square a 4-velocity is normalized to the speed of light.

Interpretationally, this can be taken to mean that you are always moving at the speed of light through spacetime. In your own rest frame, your 4-velocity vector points entirely in the time direction. If you travel at the speed of light in, say, the X direction, your 4-velocity vector points entirely in the Vx direction, leaving none of it pointing in the time direction because its length is equal to the speed of light (as I just stated above). This is where time dilation comes from. The faster an observer sees you moving in a given spatial direction, the slower you have to be moving in time because the 4-velocity vector is always the same length.

Now, in QED, there is mathematical evidence that quantum fluctuations can give rise to particles traveling at speeds that put them outside of a light cone. There is a small leakage of the particle's path outside of where classical relativity theory says it can be. If I cared enough, I'd look up more detail in my quantum field theory books.

In practical terms, this means that nothing exceeds the speed of light. Wormholes move us into the realm of GR, but even those don't break the rules because SR is a special case of GR, and when space has a funny shape to it, all of this stuff gets a whole lot more complicated while maintaining the same fundamental tenet that, no matter how funny the manifold, you still don't get to exceed the speed of light.
 
They time traveled in DBZ hence forth I believe its possible, that show wouldn't let me down.
 
First of all "Hong Kong Scientists" Laugh. Sorry but I'll trust the western world when it comes to the majority of study in Astrophysics and general laws.

Secondly there are proposed theories that allow for faster than light speed via cosmic strings which when traveled along allow for faster than light travel. In fact there is recent proof that in different parts of the Universe allow for different light speed , parts of it have been shown to be faster than 186,000 Mps. John Webb from the University of New South Wales is one of the proponents of this theory. There are many Astrophysicists in fact now that believe Einstein is wrong , there is also proof that the Big Bang is merely a branch off of a much larger event that produced 10^10^10^7 number of different Universes and it did not simply come from a infinite point.

We even know that a newly proposed theory called "Dark Flow" is pulling galaxies , super clusters even towards a fixed point in the Universe. This theory grew from abnormal spots being shown on the Wilkinson Microwave Anisotropy Probe photo.

The point being there is new evidence being recorded every day that are slowly proving that the standard model is far from accurate and even farther from complete.
 
The speed of light is not constant... We have already proven that.There are so many variables that we don't know about out there in the universe. What do the Chinese have against time travel?
 
Jutsu said:
The speed of light is not constant... We have already proven that.There are so many variables that we don't know about out there in the universe. What do the Chinese have against time travel?
Click to expand...

I don't think it's time travel itself,but science fiction/fantasy in general they don't like. The genre itself has often been used as a roundabout way to introduce ideas that repressive regimes don't want to be spread. It's even been used in American culture to make social statements that were controversial for their time. Star Trek managed to address everything from racism to the pointlessness of the Vietnam and Cold war,they even managed to sneak in television's first interracial kiss,all at a time when such topics on conventional shows wouldn't have been allowed.
 
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