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John Fennie
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Is going back in time fundamentally ruled out by Lorentz invariance? Or not? Or is it something else?
Either as a physical transportation, or literally turning back time.Nugatory said:What exactly do you mean by "going back in time"?
John Fennie said:Either as a physical transportation, or literally turning back time.
Take t to be positive, the metric will then have all positive (or all negative) components, hence no time component.ZapperZ said:Try it. Substitute t → -t in any of the Lorentz transformation. Has anything changed?
Zz.
The t term in the metric is squared. Negating its sign has what effect?John Fennie said:But I am not sure what you are trying to have me see.
It does not have any effect on the spacetime interval, which means that having negative t is allowed.jbriggs444 said:The t term in the metric is squared. Negating its sign has what effect?
Do you believe that all possible mathematical solutions apply to the real Universe?John Fennie said:which means that having negative t is allowed.
I understand. How do you guys interpret time physically? Because even time reversal is allowed, how can one physically have say, a particle, go back in time? Is there any sort of theory on the physical applications for going backward? (Just like traveling in a spaceship is a physical application for going forward.)sophiecentaur said:Do you believe that all possible mathematical solutions apply to the real Universe?
You should, perhaps replace "means" with "could imply".
John Fennie said:How do you guys interpret time physically?
John Fennie said:Because even time reversal is allowed, how can one physically have say, a particle, go back in time? Is there any sort of theory on the physical applications for going backward? (Just like traveling in a spaceship is a physical application for going forward.)
Lorentz invariance is a fundamental principle in physics that states that the laws of nature should be the same for all observers who are moving at a constant velocity relative to each other. This means that the laws of physics should not change based on an observer's perspective or their relative motion.
The theory of relativity, developed by Albert Einstein, is a theory that explains the relationship between space and time. It includes two main principles: the principle of special relativity, which deals with the laws of physics in non-accelerating frames of reference, and the principle of general relativity, which explains the effects of gravity on the space-time continuum. Time travel is often explored in the context of the theory of relativity, as it allows for the possibility of time dilation and the bending of space-time.
There are several current theories on the possibility of time travel, including the theory of special relativity, the theory of general relativity, and the concept of wormholes. These theories suggest that time travel may be possible under certain conditions, such as traveling at near-light speeds or through the use of advanced technology.
The concept of time travel raises many philosophical questions, including its implications for causality and free will. If time travel were possible, it could potentially allow for changing events in the past and altering the future, leading to questions about the consequences and moral implications of such actions. It also challenges the idea of free will, as the possibility of traveling through time could suggest that the future is predetermined and cannot be changed.
While there have been many speculations and theories about time travel, there is currently no concrete evidence to support its existence. Some scientists have conducted experiments on subatomic particles that suggest the possibility of time travel, but this has not been proven. The concept of time travel remains largely theoretical and is still a topic of scientific research and debate.