This is not true. There is the concept of closed timelike curves (CTCs):L Drago said:But time travel to past is not possible according to Einstein's general and special relativity.
As it is physically not possible, even if we could develop a technology somehow to travel in 90-99 percent speed of light, we will be in future but won't be able to return.PeroK said:This is not true. There is the concept of closed timelike curves (CTCs):
https://en.wikipedia.org/wiki/Closed_timelike_curve
Whether these exotic solutions of the Einstein Field Equations are physically possible is another question. But, the theory permits them.
I'm not sure what you mean by that. It's physically possible to undertake a journey from Earth at sufficient relative speed that the differential ageing between the spacecraft and the Earth is significant. Whether human civilization ever achieves this capability is an open question.L Drago said:As it is physically not possible, even if we could develop a technology somehow to travel in 90-99 percent speed of light, we will be in future but won't be able to return.
I am telling it is not physically possible for CTCs to exist probably. You can correct me if I am wrong.PeroK said:I'm not sure what you mean by that. It's physically possible to undertake a journey from Earth at sufficient relative speed that the differential ageing between the spacecraft and the Earth is significant. Whether human civilization ever achieves this capability is an open question.
L Drago said:The faster we go, the slower time goes for us.
L Drago said:time would pass slowly for us
I already know that after travelling in 80-90 percent of speed and returning to earth, our age same but people in earth age would have passed some years.phinds said:I'm not clear on whether you are just using shorthand for what actually happens or if you mistakenly believe that time actually does slow down for a traveler. Just to be clear, it does not. The traveler's clock ticks away at the exact same one second per second as the stay at home's clock.
If you do not understand this concept of proper time, then you are making the common mistake of confusing time dilation with differential aging.
Which does not quite address the issue I raised, it simply (and correctly) describes the effects of differential aging.L Drago said:I already know that after travelling in 80-90 percent of speed and returning to earth, our age same but people in earth age would have passed some years.
A closed timelike curve is a theoretical path where space time is bend in such a way that you can go to past.phinds said:Which does not quite address the issue I raised, it simply (and correctly) describes the effects of differential aging.
Which (1) is not true and (2) still does not address the issue I raised.L Drago said:It is like you start somewhere in time in a CTC and no matter what you end in the same time means theoretically time travel to past is possible and a big thanks to you for changing my perspective.
I do believe that time slows down for us when we travel due to Einstein's time dilation.phinds said:Which (1) is not true and (2) still does not address the issue I raised.
Do you or do you not believe that time slows down for you when you travel?
I was telling it is like a circular loop connection between two points in space time fabric and though we will theoretically be able to time travel in past we will be stuck in that loop forever. Kindly explain where I am wrong. I am asking politely for correction.phinds said:Which (1) is not true and (2) still does not address the issue I raised.
Do you or do you not believe that time slows down for you when you travel?
AGAIN, my question is, do you or do you not believe that time slows down for you when you travel? I'm just trying to make sure you are clear on this. It has nothing to do with time loops or CTCs.L Drago said:I was telling it is like a circular loop connection between two points in space time fabric and though we will theoretically be able to time travel in past we will be stuck in that loop forever. Kindly explain where I am wrong. I am asking politely for correction.
Yes, I believe that time slows down for us when we travel. Time dilationphinds said:AGAIN, my question is, do you or do you not believe that time slows down for you when you travel? I'm just trying to make sure you are clear on this. It has nothing to do with time loops or CTCs.
L Drago said:Yes, I believe that time slows down for us when we travel. Time dilation
Thanks a lotberkeman said:
Thank you for the clarification. You are wrong of course, as you will understand after reading the link that @berkeman provided.L Drago said:Yes, I believe that time slows down for us when we travel. Time dilation
Thank you. I think I need to read articles from authentic sources like Physics forum than reading articles from random sources in internet and random videos in YouTube which do not give such a clear explanation.phinds said:Thank you for the clarification. You are wrong of course, as you will understand after reading the link that @berkeman provided.
Just to help you understand, think about this. You are now traveling at zero speed relative to the chair you are sitting in, but you are also traveling at a modest percent of the speed of light relative to a slow moving cosmic particle, and you are also traveling at almost the full speed of light relative to a particle moving in the CERN accelerator. You are, in fact, traveling at an infinite number of different speeds, all just depending on finding the right object to correlate your speed to.
In all of these, you are time dilated by different amounts. If your understanding were true then all of these different amounts of time dilation would have to be the same, which is of course mathematically nonsensical.
From reading some sources. I think this is correct.phinds said:I'm not clear on whether you are just using shorthand for what actually happens or if you mistakenly believe that time actually does slow down for a traveler. Just to be clear, it does not. The traveler's clock ticks away at the exact same one second per second as the stay at home's clock.
If you do not understand this concept of proper time, then you are making the common mistake of confusing time dilation with differential aging.