Can Negative Speed of Light Allow Time Travel?

AI Thread Summary
The discussion centers on the concept of time travel and the implications of traveling at or beyond the speed of light. It is noted that while time dilation occurs for someone moving close to the speed of light, it does not allow for time travel or a reversal of time. The idea of negative speed of light is dismissed, as it contradicts established physics principles. The conversation also touches on the paradoxes associated with faster-than-light travel and the subjective experience of time for different observers. Ultimately, the consensus is that time travel, as commonly envisioned, is not feasible within our current understanding of physics.
hty226
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i am only a year 11 student so i don't know much about the Theory of relativity
i just heard that if we can travel at the speed of light our time will be slower than the other
so i am just wondering if we can travel at a negative speed of light that means that we can go back in time?
 
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I think the idea is, if you travel faster than C or the speed of light we would go backwards in time.

I think this goes against Entropy. Like you can burn a stick in a fire but you cannot un-burn it.

Some people see the Universe like a clock that you can simply turn back. Other think its not possible to go back in time at all. The reason being you would have to send everything else back in time as well.

I don't know the truth either way. It seems to me like we could get close to the speed of light but never reach it with any mass as in a space ship.

Time should slow down but would the observer notice a difference? The brain does not operate faster than it does in this time.
 
You cannot travel a negative speed.

You can travel a negative velocity, depending on your coordinate system.

It is not possible to go back in time (yet, at least). The observer on the ship would not notice a time dilation with respect to his reference frame, but he would notice a time dilation for someone traveling close to the speed of light with respect to the original observer.

It is viable to say that either observer is moving, and that either observer is stationary.
 
We can't go back in time. Simple as that. It does make since that going faster than the speed of light would make you go back in time but absolutely nothing can go faster since something would need an infinite amount of energy to do so. You also can't have negative speed. That would be like saying something is negative in distance. There's just no such thing.
 
I don't quite understand your question. The speed of light as a magnitude doesn't have a sign. There is however a space - time in general relativity described by the Godel Metric where there exist closed timelike curves such that a particle can go forward then backward in time in a "loop" like fashion in a rotating universe but this metric doesn't describe a realistic geometry by our understanding.
 
There is no "universal time". There is only time as experienced by observers (us) and time experienced by the matter of the universe.

To get straight to your question, here's how it works: If you were to travel really really fast (99.99% the speed of light) for some period of time, you would experience only a few seconds of time while Earth (and its inhabitants) experience years and years of time.

It's more of an "anti-aging" theory than anything.
 
hty226 said:
i am only a year 11 student so i don't know much about the Theory of relativity
i just heard that if we can travel at the speed of light our time will be slower than the other
so i am just wondering if we can travel at a negative speed of light that means that we can go back in time?

No.
The time will be slower for YOU, but NOT anything else.
That is, your human metabolism will be affected, but NOT the Universe.
Thus, no time travel.
 
pallidin said:
No.
The time will be slower for YOU, but NOT anything else.
That is, your human metabolism will be affected, but NOT the Universe.
Thus, no time travel.

So traveling faster than the speed of light would cause you yourself to experience time backwords...meaning you would never set out on the trip or anything else...oh the paradoxes!

But not really, as one cannot travel faster than the speed of light.
 
pallidin said:
No.
The time will be slower for YOU, but NOT anything else.
That is, your human metabolism will be affected, but NOT the Universe.
Thus, no time travel.

Actually any stationary observer relative to an observer observing you moving close to the speed of light will be slower. Your time will remain unaffected.

Thats a tongue twister.
 
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