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Tony.K
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Hi, I want to know from proffesionals if time travel is physically possible.
Thanks,
Tony
Thanks,
Tony
Topher925 said:Oh, you mean the THEORY of special relativity?
Tony.K said:Hi, I want to know from proffesionals if time travel is physically possible.
Thanks,
Tony
If every physical process experienced exactly the same time dilation, how would you differentiate between physical processes slowing down and time itself slowing down? And why would it not be easier to unify it under the heading of "time dilation" and consider it to be a single concept?Raap said:I don't see a need to actually take the 'time is relative' part into the equation. A process that might take 1 second at 'normal speed' could take 2 seconds at a higher speed; just means the process went slower, not that *time* did.
Well, maybe it would, I just feel it's sort of misleading. I'd rather we kept the term 'time' as a global constant, i.e. always from the observer's pov, instead of making it a local variable. Maybe just renaming it to something which doesn't include the word 'time'? *shrug*russ_watters said:If every physical process experienced exactly the same time dilation, how would you differentiate between physical processes slowing down and time itself slowing down? And why would it not be easier to unify it under the heading of "time dilation" and consider it to be a single concept?
I don't follow. What would this change? The speed of light is correct in relation to how we measure it, taking into account the movement our planet( not to mention solar system and galaxy ). But since it's all relative, moving to another galaxy would make the speed of light faster or slower since the clocks we measured it with over there would experience a different 'time dilation'. Here it might be 300,000,000'ish meters a second, there it might be 310,000,000'ish. Not because the light moved faster, but because the atomic processes in the clock moved faster, causing the 'second' to be shorter.russ_watters;1955086[/quote said:If we concluded that clocks run slow but time doesn't, that would mean our measurements of the speed of light are wrong - but our measurments agree with SRT.
Raap said:Well, maybe it would, I just feel it's sort of misleading. I'd rather we kept the term 'time' as a global constant, i.e. always from the observer's pov, instead of making it a local variable. Maybe just renaming it to something which doesn't include the word 'time'? *shrug*
If we concluded that clocks run slow but time doesn't, that would mean our measurements of the speed of light are wrong - but our measurments agree with SRT.
I don't follow. What would this change? The speed of light is correct in relation to how we measure it, taking into account the movement our planet( not to mention solar system and galaxy ). But since it's all relative, moving to another galaxy would make the speed of light faster or slower since the clocks we measured it with over there would experience a different 'time dilation'. Here it might be 300,000,000'ish meters a second, there it might be 310,000,000'ish. Not because the light moved faster, but because the atomic processes in the clock moved faster, causing the 'second' to be shorter.
I'm not sure why concluding that 'clocks run slower but time doesn't' would change anything.
If we concluded that clocks run slow but time doesn't, that would mean our measurements of the speed of light are wrong - but our measurments agree with SRT.
I'd argue that time doesn't really go forwards or backwards at all, it just is. Mass/energy and movement is all that matters.
You are seeing the clock on alpha centauri to run slower, while the creature on alpha centauri sees your clock as moving slower. That's it.
It is important to understand that there is no "absolute frame of reference" whereby we could ever, even in principle, determine whether time is slow or fast. Frames of reference and their measurements of time are only relative to each other.Topher925 said:I completely agree. In my mind we have absolutely no way of measuring "time" itself just the processes that happen in a chronotomic (yeah, I made that word up) order. The fact that time can change by any means is to me highly illogical, although I do understand the concept of time dilation and the reasoning behind it. While I do comprhend time dilation and how it relates to the speed of light, I can not physically comprehend how time can not be constant given any frames of reference.
ZapperZ said:You have a severe misunderstanding of Special Relativity and time dilation.
You can move to anywhere, and the speed of light would STILL be measured the same! That's the main postulate of SR, that in ANY inertial reference frame, each observer in that frame will ALL measure light be moving at c. No exception! In fact, two observers in two different frames sees the SAME light moving at c in each of their own frame!
What this means is that the "time dilation" that is being seen is what YOU see of the time in the OTHER frame. You see no change in your time, no matter where you are, and no matter in which frame you are in! It is only from the point of view of an observer in a DIFFERENT frame is your time slower, not from your own observation of your own time!
You are seeing the clock on alpha centauri to run slower, while the creature on alpha centauri sees your clock as moving slower. That's it.
Zz.
It is.Raap said:I realize you don't notice the dilation in your own time, but let me try an example so I can see where my understanding is wrong. If you're in a spaceship doing 99% lightspeed for 1 second ( earth-observer time ), you, as a passenger in the ship, will only register a fraction of that time( though to the passengers everything appeared normal ), correct so far? The Earth clock goes 1 second, while the ship's clock goes, let's say 0.1 second to make it simple.
Then, if both the Earth and the Ship started measuring the same photon immediately after the ship went to near-lightspeed, they both would have registered that the photon traveled 299,800,000'ish meters. However, the earth-clock would say the photon traveled that distance in 1 second, while the ship clock would say it traveled the distance in 0.1 second.
This is incorrect?
WarPhalange said:One thing I haven't been able to resolve is that if you have a guy standing still and another guy going 0.5c, time is experienced slower by the guy going 0.5c, right? But in that guy's point of view, you are going at 0.5c, so you should have the slower time. What gives? Is it because one of them accelerated more than the other some time in the past, ergo that is the one who is "moving" relative to the other one?
No, what happened in their past is not relevant. Yes, they both observe the other one moving slower. The apparent paradox is resolved when you realize that simultaneity of events is also relative.WarPhalange said:One thing I haven't been able to resolve is that if you have a guy standing still and another guy going 0.5c, time is experienced slower by the guy going 0.5c, right? But in that guy's point of view, you are going at 0.5c, so you should have the slower time. What gives? Is it because one of them accelerated more than the other some time in the past, ergo that is the one who is "moving" relative to the other one?
Tony.K said:Hi, I want to know from proffesionals if time travel is physically possible.
Thanks,
Tony
DaleSpam said:My understanding is that closed timelike curves (travel to your past) are compatible with General Relativity, but the solutions usually require exotic matter.
Topher925 said:Back to the OP's original question, how is it that according to SRT, that you can actually give time a positive time dilation?
DaveC426913 said:For two, they would disagree on the timing of events. Having both observed some objective experiment (such as turning on a flashlight aimed at a target) they would have different accounts of how long certain events took and what distances were measured.
It's a bit more complex than that; it's not simply the light lag; you could likely revise the experiment to factor that out (for example, by having the two spaceship fly past each other with little distance).WarPhalange said:I see, so if both of them were somehow looking at the other guy (say actually just a projected image towards the observer) to see who dies first of old age, and they both happened to kick the bucket at the same time, they would both see themselves die first because light from the other guy hasn't reached them yet. Is that right?
At this point in time, there is no scientific evidence to support the idea that time travel is physically possible. However, some theories in physics, such as general relativity, suggest that time travel may be possible under certain conditions.
One of the main obstacles to time travel is the inability to travel faster than the speed of light. According to Einstein's theory of relativity, as an object approaches the speed of light, time dilates, making it difficult or impossible to travel back in time. Additionally, the paradoxes and logical inconsistencies that arise from time travel theories make it difficult to determine if it is truly possible.
Some proposed methods for time travel include using wormholes, cosmic strings, and black holes. However, these methods are purely theoretical and are not currently achievable with our current technology.
The concept of changing the past through time travel is a source of much debate and speculation. Some theories suggest that changing the past would create a paradox, while others propose the idea of multiple timelines or parallel universes. Ultimately, the answer to this question is still unknown and based on theoretical speculation.
The ethics of time travel is a complex and highly debated topic. Some argue that changing the past could have unforeseen consequences and potentially disrupt the natural course of events. Others argue that the ability to travel through time could bring about significant advancements and benefits for humanity. Ultimately, the ethical implications of time travel are largely subjective and dependent on individual beliefs and values.