Could Quantum Gravity Allow Us To Time Travel?

[Vmedvil2]

There is currently a discussion about whether or not time travel would be possible under Quantum Gravity in different theories, Read More at https://www.forbes.com/sites/fernandezelizabeth/2019/09/09/could-quantum-gravity-allow-us-to-time-travel/#598fe272f2a5

Edited January 17, 2020 by VictorMedvil

[Mutex]

 

While general relativity does a great job at predicting how macroscopic objects like stars and planets move and interact, it is not a fundamental explanation of the Universe. It doesn't take into account the very small, weird world of quantum mechanics.

 

I think it's time for a bit of a scientific rant, being triggered and all.

 

The number of observations, tests, experiments that shows that relativity is wrong or incomplete on ANY scale are wrong?  ZERO

 

The number of observations, tests, experiments that shows that the universe is quantum mechanical in nature? Possibly one, but very speculative.

 

And, no, you can't say "but relativity breaks down in black holes", you can't say that because you don't know that, it is speculation only so that conclusion is not science based.

 

Relativity does not really 'just' explain or predict "how macroscopic objects like stars and planets move and interact". That might sound nice for the Sci Fi or amateur science fans.

 

Relativity tells us something about the nature of space and time, planets and objects exist is said space and time is it does tell us something about what things do in space and time.

 

What does quantum mechanics tell us?

 

What insight does quantum mechanics give us about how nature works and how the universe works? What does it tell you, what more do you UNDERSTAND about the universe from quantum mechanics? 

 

There is no coherent theory of quantum mechanics, but I won't rant, it is at best inconsistent and incomplete, and at worst it's just completely wrong.

 

However with relativity, it actually provides an accurate description of the nature of space and time (even though I don't agree with space being geometrical in nature), no predictions or observations contradict it. 

 

In quantum mechanics, it is not possible to model or predict something like a proton, QM comes up with an accurate number for the magnetic moment and precession of an electron in a magnetic field.... And that's about it!

 

Even providing a number for that electron precession "from first principles" does not sit well with me. 

 

You don't just get a specific number from 'first principles', you have to start with numbers, you cannot just get the speed of light by applying e=mc², So when David Tong tells me that they can calculate g to 12 decimal places therefore quantum mechanics is the ONLY model that exists, I don't buy that. 

David then goes on (in his lecture) that after the electron he basically states that "quantum mechanics is wrong".

 

this is the link to the lecture I am referring too, to go about the 27 minute mark, but keep watching, because after saying how quantum mechanics is 'the greated theory ever" he then goes on to say that after the electron things fall apart.

 

Go 29 minutes in:

 

 

It's simply spectacular, there is nothing like this anywhere else in science, with an agreement between the theoretical calculation and the experimental measurements, 12 or 13 significant figures..

 

I am sure, that if you could measure the speed of light to that accuracy then you could say that is nothing like anything else in science.

The real achievement here is in experimental physics. You can't use that as cred for your theory.

 

And again, for you to be able to spit out an actual number from your 'first principles' you first have to have real numbers as inputs to the equation, and all those numbers have to be to the same precision. 

 

I am almost certain (deliberatively not having looked at how they measure this parameter), that they are looking at essentially Faraday Rotation from the electron perspective, and I bet they are doing it statistically as a result of light polarisation measurements, they would be coming up with a probability that it is NOT, NOT this number..  That is not the same thing as measuring it. 

 

Any take a look at that lecture, with a critical eye.

 

 

29:40 "there are MANY other results that are NOWHERE NEAR AS GOOD"

 

That's not good! (in science that generally means it's wrong, at least it's supposed too) ok one more:

 

 

It should be possible for us to sit down and calculate, from first principles the mass of the proton. We have the equations, everything should be there we just need to work hard and figure it out what the mass of the proton is just by doing the calculations, WE HAVE BEEN TRYING TO DO THIS FOR ABOUT 40 YEARS NOW!!!!

 

This is why I'm not a huge fan of quantum mechanics, it does not really explain anything, it gives no insight, it certainly does not explain space or time or motion, or as far as I can see any real aspect of nature. 

 

Then you get the people who will say "We'll you just don't understand quantum mechanics", that's right I don't but neither do you, neither does ANYONE, because there is nothing to understand..

 

That's my Poo poo quantum mechanics rants for you, I hope I did not upset you.. Just remember in one of the many worlds you are glad that I said it (just not in this one)..

 

TIME TRAVEL: I got so excited about bagging QM that I forget about time travel..

 

Got some bad news for you, time travel is not a thing, it will never be a thing, it does not exist. 

 

If you went back in time just 1 second you would be in a place that has no universe, no matter, no energy no space, no time no nothing (except you). 

 

You would be the entire universe the only matter, energy, time or space is from you. The past does not exist 'somewhere' waiting for us to go there and relive it, just as the future does not exist.

 

Let me put it another way, past time and future time do not exist, what we perceive as 'past time' is simply 'now' time with a delay from the length of space (spacetime), or distance time. That supernova you watched from a star 10 light years away did not happen 10 years ago, it happened 'now' in our 10 years ago and it has taken 10 years for that now to get to our now. Nothing is in the past, it is just separated by a length of space and light has a finite speed.

 

If you could instantly beam to that distant star, you would notice that the supernova happened 10 years ago! If the speed of light was infinite, we both would have witnessed that event 10 years ago. 

 

In our universe we have space and space length based time (spacetime), only spatial time, no temporal time (past and future do not exist, anywhere or anytime).

 

Also blackhole inducted wormholes, it not going to get you anywhere and certainly it will not get you into the past or the future. 

Even if you could invent an instant teleportation device to anywhere in the universe, you will not ever be able to travel a picosecond into the past or the future.. 

 

But I'm sure that does not sounds nearly as sexy as being able to go back in time! or that things are 'waves or particles or both' and something 'spooky'.. 

 

So yay relativity (never shown to be wrong)

Boo quantum mechanics hype (often, usually wrong)

and

Bad news for wannabe time travelers.. (no past or future exists)

 

Science is not about proving yourself right, it's about proving yourself wrong, don't ever forget that basic principle of the scientific method, if you can't prove yourself wrong, put it up for peer review and see if they can prove you wrong. After than you might have a chance at actually being right. 

 

If you have a theory and set out to prove yourself right, then you will only look at things that show you are right, and you will not look at things that show you are wrong.

 

The precession of the electron (g) in a magnetic field does not prove QM is right, however many other observations and predictions do prove that it is wrong.. 

 

I end my rant.. 

 

Mutex: Allows multiple program threads to share the same resources and data, we all see the same data, it's just how you look at and interpret when you see..

[Vmedvil2]

I think it's time for a bit of a scientific rant, being triggered and all.

 

The number of observations, tests, experiments that shows that relativity is wrong or incomplete on ANY scale are wrong?  ZERO

 

The number of observations, tests, experiments that shows that the universe is quantum mechanical in nature? Possibly one, but very speculative.

 

And, no, you can't say "but relativity breaks down in black holes", you can't say that because you don't know that, it is speculation only so that conclusion is not science based.

 

Relativity does not really 'just' explain or predict "how macroscopic objects like stars and planets move and interact". That might sound nice for the Sci Fi or amateur science fans.

 

Relativity tells us something about the nature of space and time, planets and objects exist is said space and time is it does tell us something about what things do in space and time.

 

What does quantum mechanics tell us?

 

What insight does quantum mechanics give us about how nature works and how the universe works? What does it tell you, what more do you UNDERSTAND about the universe from quantum mechanics? 

 

There is no coherent theory of quantum mechanics, but I won't rant, it is at best inconsistent and incomplete, and at worst it's just completely wrong.

 

However with relativity, it actually provides an accurate description of the nature of space and time (even though I don't agree with space being geometrical in nature), no predictions or observations contradict it. 

 

In quantum mechanics, it is not possible to model or predict something like a proton, QM comes up with an accurate number for the magnetic moment and precession of an electron in a magnetic field.... And that's about it!

 

Even providing a number for that electron precession "from first principles" does not sit well with me. 

 

You don't just get a specific number from 'first principles', you have to start with numbers, you cannot just get the speed of light by applying e=mc², So when David Tong tells me that they can calculate g to 12 decimal places therefore quantum mechanics is the ONLY model that exists, I don't buy that. 

David then goes on (in his lecture) that after the electron he basically states that "quantum mechanics is wrong".

 

this is the link to the lecture I am referring too, to go about the 27 minute mark, but keep watching, because after saying how quantum mechanics is 'the greated theory ever" he then goes on to say that after the electron things fall apart.

 

Go 29 minutes in:

 

 

I am sure, that if you could measure the speed of light to that accuracy then you could say that is nothing like anything else in science.

The real achievement here is in experimental physics. You can't use that as cred for your theory.

 

And again, for you to be able to spit out an actual number from your 'first principles' you first have to have real numbers as inputs to the equation, and all those numbers have to be to the same precision. 

 

I am almost certain (deliberatively not having looked at how they measure this parameter), that they are looking at essentially Faraday Rotation from the electron perspective, and I bet they are doing it statistically as a result of light polarisation measurements, they would be coming up with a probability that it is NOT, NOT this number..  That is not the same thing as measuring it. 

 

Any take a look at that lecture, with a critical eye.

 

 

That's not good! (in science that generally means it's wrong, at least it's supposed too) ok one more:

 

 

This is why I'm not a huge fan of quantum mechanics, it does not really explain anything, it gives no insight, it certainly does not explain space or time or motion, or as far as I can see any real aspect of nature. 

 

Then you get the people who will say "We'll you just don't understand quantum mechanics", that's right I don't but neither do you, neither does ANYONE, because there is nothing to understand..

 

That's my Poo poo quantum mechanics rants for you, I hope I did not upset you.. Just remember in one of the many worlds you are glad that I said it (just not in this one)..

 

TIME TRAVEL: I got so excited about bagging QM that I forget about time travel..

 

Got some bad news for you, time travel is not a thing, it will never be a thing, it does not exist. 

 

If you went back in time just 1 second you would be in a place that has no universe, no matter, no energy no space, no time no nothing (except you). 

 

You would be the entire universe the only matter, energy, time or space is from you. The past does not exist 'somewhere' waiting for us to go there and relive it, just as the future does not exist.

 

Let me put it another way, past time and future time do not exist, what we perceive as 'past time' is simply 'now' time with a delay from the length of space (spacetime), or distance time. That supernova you watched from a star 10 light years away did not happen 10 years ago, it happened 'now' in our 10 years ago and it has taken 10 years for that now to get to our now. Nothing is in the past, it is just separated by a length of space and light has a finite speed.

 

If you could instantly beam to that distant star, you would notice that the supernova happened 10 years ago! If the speed of light was infinite, we both would have witnessed that event 10 years ago. 

 

In our universe we have space and space length based time (spacetime), only spatial time, no temporal time (past and future do not exist, anywhere or anytime).

 

Also blackhole inducted wormholes, it not going to get you anywhere and certainly it will not get you into the past or the future. 

Even if you could invent an instant teleportation device to anywhere in the universe, you will not ever be able to travel a picosecond into the past or the future.. 

 

But I'm sure that does not sounds nearly as sexy as being able to go back in time! or that things are 'waves or particles or both' and something 'spooky'.. 

 

So yay relativity (never shown to be wrong)

Boo quantum mechanics hype (often, usually wrong)

and

Bad news for wannabe time travelers.. (no past or future exists)

 

Science is not about proving yourself right, it's about proving yourself wrong, don't ever forget that basic principle of the scientific method, if you can't prove yourself wrong, put it up for peer review and see if they can prove you wrong. After than you might have a chance at actually being right. 

 

If you have a theory and set out to prove yourself right, then you will only look at things that show you are right, and you will not look at things that show you are wrong.

 

The precession of the electron (g) in a magnetic field does not prove QM is right, however many other observations and predictions do prove that it is wrong.. 

 

I end my rant.. 

 

Mutex: Allows multiple program threads to share the same resources and data, we all see the same data, it's just how you look at and interpret when you see..

 

You could be correct about no past existing as movement in the temporal direction happens the past could be replaced by the future with nothing remaining, that is something I have often thought about is there could be no "past" to proceed to however it is known that time slows down as particles accelerate it is possible that the universe doesn't work like that, upon using a closed time-like curve you could see a effect like the relativistic time dilation where the universe begins to phase-shift backward as the general speed of time is relative to the energy in such a location. Either possibility is possible it is unknown what would actually happen if a Tipler Cylinder was created making a path to the foreseeable past. I can tell you what a reverse time travel device would look like under general relativity however when it makes those closed time-like curves it is unknown to how the universe would react from the time dilation effect of special relativity it would seem that, the universe would just change its phase-shift backward however it could be that the universe would not as the configuration of the entire universe would have to change in the reverse in this situation upon direction dt. The real question is does the configuration of the entire universe change because of Closed Time-like curves? My point being this does the universe cease to exist because of a slowing in the passage of time because of Special Relativistic Time Dilation, the answer is No but that only changes time in a local volume because of energy-mass not the entire universe's energy configuration.

 

 

Edited January 22, 2020 by VictorMedvil