Speed of light beaten - time travel possible!

[Mickymoody]

Go look at a nuclear reactor sometime. Cherenkov radiation.

Well whaddya know? Funny how they didn't mention that on that relativity course I did at college. To$$ers

I did that course at school...it was "relatively" easy.

D'Oh That definitely had me reaching for the alert button

Not really - hit the alert button! Radiation fields, and time space taught in schools? We were sent out to dig up worms, and make egyptian style bricks...maybe I went to the wrong school.

 

[freddiemercurystwin]

maybe I went to the wrong school

You went to school! God help us!

 

[Space cat]

While the results of this experiment may be consistent, as of yet it has not been independently verified, and we cannot treat it as such.

Quite right. The theory of relativity has stood for a long time. It'll take some very good experimental evidence to knock it down. Might I suggest that one way to improve the accuracy of this experiment is to increase the distance. It shouldn't be too difficult to set up a source and detector on opposite sides of the planet.

Meanwhile, what's all this time travel business. I keep hearing it on the news and I get the distinct impression that a lot of people are jumping to a lot of highly dubious conclusions.

What could you do with faster than light travel? Well, one thing you could do, in theory, is look back and see yourself leave. But is this really time travel? I don't think so. All you're doing is observing what's already happened. You can observe the effect (arrival) before the cause (leaving). What you can't do is observe the effect then go back and change the cause, which is what true backwards time travel would allow.

Maybe you've seen one of those diagrams in a physics book that shows a cone standing point downwards on top of another. The point where the two meet represents your present position in a 2D space (3D is too difficult to draw). The upper cone contains all the points that you can reach without exceeding the speed of light while the lower cone contains all the points that you could have come from.

So far so good but all the books I've read jump to a rather nebulous conclusion, namely that faster than light travel will allow you to escape from the upper cone (which it will) and re-enter the lower one. This is not at all obvious. It's not even clear that the lower cone (your past) still exists. As I once said in another thread, to achieve true backwards time travel you would have to restore the universe to an earlier state, something that the second law of thermodynamics will not allow.

 

[cantaloup63]

So far so good but all the books I've read jump to a rather nebulous conclusion, namely that faster than light travel will allow you to escape from the upper cone (which it will) and re-enter the lower one. This is not at all obvious. It's not even clear that the lower cone (your past) still exists. As I once said in another thread, to achieve true backwards time travel you would have to restore the universe to an earlier state, something that the second law of thermodynamics will not allow.

Indeed, Stephen King explains it in one of his short stories from "Three Past Midnight" - time monsters come along and chomp the past up.

Star wars has an interesting way of explaining "travelling" at speeds seemingly faster than light. The idea is that you bend (warp) space up into waves and then hop from one peak to another, thus obviating the need to remain path-connected along the "surface" of space. A bit like finding that elusive shortcut through IKEA

 

[Shutpa]

There may come a time when you decide to go for a pint and get to the pub and drink your pint before you leave the house. Then you decide that you dont want to go to the pub after all, stay in and save yourself the money having already had your pint.

 

[cantaloup63]

There may come a time when you decide to go for a pint and get to the pub and drink your pint before you leave the house. Then you decide that you dont want to go to the pub after all, stay in and save yourself the money having already had your pint.

But then you'd be in breach of an intended contract between you and the publican. The potential legal fees would be prohibitive, so it's best that you go for the drink after all

 

[Shutpa]

There may come a time when you decide to go for a pint and get to the pub and drink your pint before you leave the house. Then you decide that you dont want to go to the pub after all, stay in and save yourself the money having already had your pint.

But then you'd be in breach of an intended contract between you and the publican. The potential legal fees would be prohibitive, so it's best that you go for the drink after all

You're quite right! The pub it is!

 

[Space cat]

A bit like finding that elusive shortcut through IKEA

Surely that's a myth concocted by clever marketing men who hope you'll buy something while you're looking for it.

 

[cantaloup63]

A bit like finding that elusive shortcut through IKEA

Surely that's a myth concocted by clever marketing men who hope you'll buy something while you're looking for it.

IKEA does seem to bend the laws of relativistic physics - minutes do feel like hours, eating their hotdogs does provide you with no energy whatsoever and most curiously of all, a walk of a few hundred feet in there does seem to make one's body mass greater if the pain in one's feet is anything to go by The Lorentz factor (1-v^2/c^2) may well be kicking into play.

On the subject of IKEA (teensly hijack, but loosely related to the op), I'm sure that the weight of that blo0dy furniture is bending space.

 

[Nige F]

WTF do I know - but it`s Sub atomic particles with no charge nor weight - so how can they influence atoms , let alone the laws of ( atomic ) physics. They are more likely to explain " paranormal " events than time travel - eventually ...or maybe they just did but were erased in the past

 

[cantaloup63]

They are more likely to explain " paranormal " events than time travel - eventually ...or maybe they just did but were erased in the past

Blooming mods, deleting things that they don't comprehend. Goes on everywhere

 

[Space cat]

Sub atomic particles with no charge nor weight - so how can they influence atoms

Neutrinos are curious little blighters. They have no charge but some at least must have mass because they travel at sub light speed. The story of the neutrino is interesting because it was postulated before it was discovered (rather like Neptune and Pluto). Physicists noticed that there was something wrong with beta decay - the momentum and energy just didn't add up - and so there had to be a third particle involved:

n -> p + e + ?

With no charge and minimal mass, they're damnably difficult to detect because they can slide straight through atoms as if they weren't there. I think the first neutrino detector was an underground tank filled with hundreds of gallons of some liquid containing chlorine. (With three neutrons too many, chlorine 37 is a borderline candidate for beta decay so that makes sense.) The truly amazing thing about this experiment was that it worked at all because it involved counting argon atoms. A few tens of argon atoms in a huge tank of liquid and you have to count them!!!

The upshot was that only one third of the expected solar neutrinos were found. Later experiments with detectors that could find all three types showed that the solar neutrinos - which are all of the same type - had transmuted in transit. The fact that they had time to do this showed that they were travelling at sub light speed and thus they must have mass.

So what of the CERN neutrinos which appear to be travelling faster than light? Well, relativity does not actually preclude this. What it says is that a sub light speed particle can never exceed - or even reach - light speed. It also says that a super light speed particle is also trapped and cannot slow down to below light speed!

 

[cantaloup63]

Apart from the obvious explanation that neutrinos are in fact being sent to us by God as a test of our faith , could it have been the case that the original detectors were detecting particles that were travelling faster than light but that they were not calibrated to measure the speed unlike the current arrangements?

Or, could it be that I'm completely out of my depth ...


Back to basics for me then...

Hail Mary, full of grace
Hail Mary, full of grace
Hail Mary, full of grace
Hail Mary, full of grace
Hail Mary, full of grace
Hail Mary, full of grace...

 

[Space cat]

could it have been the case that the original detectors were detecting particles that were travelling faster than light but that they were not calibrated to measure the speed unlike the current arrangements?

The answer to that has to be "yes". As far as I know, this recent experiment is the first time anybody has measured the speed of a neutrino. You can't just look at one as it flies past. Even if you did manage to bounce some light off one, the mere act of observing it would knock it off course. Solar neutrinos are assumed to travel at sub light speed for one reason only: they have time to transmute before they reach us. Light speed 'particles' (I don't entirely believe in photons) can't do this because they exist in frozen time - as seen by us.

 

[cantaloup63]

Holy Mary, Mother of God, pray for us sinners now and at the hour of our death. Amen

I have seen the light...