Posted on 10/01/2020 10:13:13 AM PDT by Red Badger
No one has yet managed to travel through time – at least to our knowledge – but the question of whether or not such a feat would be theoretically possible continues to fascinate scientists.
As movies such as The Terminator, Donnie Darko, Back to the Future and many others show, moving around in time creates a lot of problems for the fundamental rules of the Universe: if you go back in time and stop your parents from meeting, for instance, how can you possibly exist in order to go back in time in the first place?
It's a monumental head-scratcher known as the 'grandfather paradox', but now a physics student Germain Tobar, from the University of Queensland in Australia, says he has worked out how to "square the numbers" to make time travel viable without the paradoxes.
"Classical dynamics says if you know the state of a system at a particular time, this can tell us the entire history of the system," says Tobar.
"However, Einstein's theory of general relativity predicts the existence of time loops or time travel – where an event can be both in the past and future of itself – theoretically turning the study of dynamics on its head."
What the calculations show is that space-time can potentially adapt itself to avoid paradoxes.
To use a topical example, imagine a time traveller journeying into the past to stop a disease from spreading – if the mission was successful, the time traveller would have no disease to go back in time to defeat.
Tobar's work suggests that the disease would still escape some other way, through a different route or by a different method, removing the paradox. Whatever the time traveller did, the disease wouldn't be stopped.
Tobar's work isn't easy for non-mathematicians to dig into, but it looks at the influence of deterministic processes (without any randomness) on an arbitrary number of regions in the space-time continuum, and demonstrates how both closed timelike curves (as predicted by Einstein) can fit in with the rules of free will and classical physics.
"The maths checks out – and the results are the stuff of science fiction," says physicist Fabio Costa from the University of Queensland, who supervised the research.
The new research smooths out the problem with another hypothesis, that time travel is possible but that time travellers would be restricted in what they did, to stop them creating a paradox. In this model, time travellers have the freedom to do whatever they want, but paradoxes are not possible.
While the numbers might work out, actually bending space and time to get into the past remains elusive – the time machines that scientists have devised so far are so high-concept that for they currently only exist as calculations on a page.
We might get there one day – Stephen Hawking certainly thought it was possible – and if we do then this new research suggests we would be free to do whatever we wanted to the world in the past: it would readjust itself accordingly.
"Try as you might to create a paradox, the events will always adjust themselves, to avoid any inconsistency," says Costa. "The range of mathematical processes we discovered show that time travel with free will is logically possible in our universe without any paradox."
The research has been published in Classical and Quantum Gravity.
Ever read "The Billiard Ball" by Isaac Asimov? A great short story that illustrates what you mentioned about space/time.
The reason you don't notice that you have moved thousands of miles is because you are observing the universe from your own inertial field. In fact, there is no point in the universe which one can say is static, except the place you are observing it from, or some other arbitrary point which you might choose. You might just as well say that you are not moving, while universe is moving around you, as to say you are moving through the universe.
Agreed.
This physicist may have done no more than determine He has arranged for multiple realities that a select few can experience.
Why would they come back here? They would go to a time when there was no mass communications to study the places and people, like Ancient Rome or Greece...................
But would the T. rex remember Joe?
Yes, I have read it many times...One of my faves.................................
I remember reading about that in the future..
Niven’s Law:
If the universe of discourse permits the possibility of time travel and of changing the past, then no time machine will be invented in that universe.
Simply, if time travel that could change the past was possible, then time travel would be invented and would keep changing the past until a universe came to be where time travel will not be invented. Therefore time travel, if possible, will not be invented our universe because the above would already have occurred.
Put that in your pipe and smoke it.
T. rex would not be interested. Old meat is tough
I knew that already.
Not true
If your description were accurate we wokk UK LS already be frozen in deep space
I would postulate that time is in constant motion in a direction. To travel with time (what we are currently doing) requires no additional effort as we are being “carried” by time. To travel either forward or backward, one would need to move outside of time.
John Titor on YouTube claimed to have been a time traveler from 2036
He said the device was powered by 2 tiny black holes created at CERN.
The time travel was created by injecting electrons that would drag you through time.
He had a picture of the device, and a very military-looking operators manual. If it was a hoax it was an extremely well designed hoax.
I can’t get enough of it.
I travel through time, all the time.
October 1, 2020, 10:44, soon to be 10:45, and continuing...
Nano second by nano second.
Not possible. But I guess string hypothesis gets old sometimes.
Yeah, a couple of us had a good laugh over this next week.
Why would I want to travel into the past? To watch love ones die again? To watch loved one suffer from disease? To experience the love that recall to this day—as clearly as I felt it then? But miss the person with who I shared it?
No thanks. My mind tortures me with that every night.
My future is relatively short. And while I am in fine shape today...the good days coming are outweighed by the bad days that are inevitable.
The ultimate good days will last forever—so there is time to wait for them.
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