Can Negative Speed of Light Allow Time Travel?

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Discussion Overview

The discussion revolves around the concept of time travel in relation to the speed of light, particularly the idea of negative speed of light and its implications for traveling back in time. Participants explore theoretical aspects of relativity, time dilation, and the nature of time itself.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants suggest that traveling faster than the speed of light could allow for backward time travel, while others argue that this contradicts the concept of entropy.
  • One participant mentions that negative speed is not a valid concept, although negative velocity can be defined depending on the coordinate system.
  • There is a discussion about the observer's experience of time dilation, with some stating that an observer traveling close to the speed of light would not notice time passing differently for themselves, but would observe differences relative to stationary observers.
  • Several participants assert that time travel is not possible, citing the need for infinite energy to exceed the speed of light and the impossibility of negative speed.
  • A participant introduces the Godel Metric from general relativity, which theoretically allows for closed timelike curves, but notes that this does not represent a realistic scenario.
  • There is a recurring emphasis that while time may slow down for the traveler, it does not affect the universe as a whole, leading to the conclusion that time travel is not feasible.

Areas of Agreement / Disagreement

Participants generally agree that traveling faster than the speed of light is not possible and that time travel, as commonly conceived, is not achievable. However, there are competing views regarding the implications of traveling at or near the speed of light and the theoretical constructs that might allow for time travel.

Contextual Notes

Some claims rely on specific interpretations of relativity and the nature of time, which may not be universally accepted. The discussion includes assumptions about energy requirements and the definitions of speed and time.

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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