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.
You would have to compensate for motion.
The entire Universe is constantly in motion.
Planets move. Their stars move. Their galaxies move.
In just one minute you have moved thousands of miles in space and don't even notice it.
So if you traveled in TIME, you would most likely end up immediately frozen in deep space with nothing much around you...................
“A physicist has APPARENTLY...”
Fixed.
I am your own Grandma! LOL.
Damn. So no do-overs of the many mistakes of my past?
Send Biden to meet T rex
Hey! A high minded science thought that I can actually grasp!
This is a good one!
No. Humans and every animate being and inanimate object are firmly embedded in the cause/effect sequence, and are incapable of leaving that mode of existence.
There is only being that stands outside of the cause/effect sequence, and that is God.
I wrote this paper 50 years from now. He stole it and came back to beat me to the punch.
Sure thing, now go sit down next to the jackass that thinks math is racist and two plus two is not really four.
I came up with math that shows me getting all A’s in school and I owe no taxes forever. And no paradox either. Cause the universe adjusts itself to be what I, in my infinite wisdom, know to be.
Nope! You get one chance....................
It seems to me that you might run into something (big) unexpectedly. The maps show where objects WERE, not where objects ARE, and the location of some of those objects are millions of light years out of date.
Time travel will never be invented, because someone would have come back to visit and that has never happened.
Go back and tell Eve to go on a diet.
Not true. An experiment was done and the result was proof that travel into the future is possible. It involved two clocks and a jet aircraft. I think we are all familiar with it.
Now...travel into the past? That is quite a bit more problematic.
A lot of folks have made very adamant statements regarding science only to be proven very wrong either a little or a lot later.
I don’t think you’ll be around long enough to find out, since it may be many, many years away, but someone will whisper it to the air and maybe you will hear it :)
There is also the ‘Conservation of Matter’ law to consider.
Every atom of your self, and any time machine you may invent, has existed in this universe and nowhere else.
If you go back to some other time, even a few minutes, that matter already exists and you would be introducing more matter into the universe that was there before. Big Bang.....................
Thanks Red Badger. Great, my time machine's almost finished.
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