Did CERN just break physics?

[Docaroo]

the theory of evolution as we know it was modelled on what had been physically observed and research into fossils etc. it has been developed as more evidence has been sought.

Exactly! The Theory of Evolution is based on our phyiscal observations!

What do you think the Theory of Relativity and Special Relativity are? They are based on phyiscal observations of the universe.

BUT, further to that, Einsteins theories also made many PREDICTIONS about the Universe. Einstein basically said, "If I am right, then we should be able to observe x, y and z happen in this way."

And do you know something... that's exactly what happens. The orbit of Mercury problem is solved by Special Relativity, also we have proved that the gravitational lensing of light really happens as predicted by Einstein.

This is a theory, with the same backing as the Theory of Evolution and perhaps even more so because there is absolutely robust mathematics going on behind relativity that would show any inconsistencies and error in the theory - which they don't!!

...
edit: I'd also like to say I'm not an armchair physicist. By no means am I an expert (4th year undergrad theoretical Physicist), but I have studied SR fairly heavily in my time .

Good to have some backup from someone who really studies it!

Again, the results will come back, neutrinos will NOT be travelling faster than c. Sorry to spoil the party

 

[Engy Benjie]

Nah. That's the equivalent of me saying that 1 / x = y is scientific theory because I have repeated the test on my computer 25,000 times (even though I am not acounting for error in my code, error in other people's code, or accounting for any rounding/FPA error in the machine).

There are still too many variables which were not changed during the repetition to go even anywhere near such a rash conclusion.

http://www.guardian.co.uk/science/2011/sep/24/einstein-e-equals-mc2

I don't know that it was exactly the same test done 16000 times, I very much doubt it was. But to quote "The CERN results are within a margin of statistical certainty that, were this not such an unexpected result, it would be considered a new discovery".

 

[BetaNumeric]

It does have an additional constant, E = gamma*MC^2 is correct for objects not at rest, where gamma = 1/sqrt(1-(v/c)^2)

Where's my Nobel prize?

Actually that's not correct as it doesn't apply to massless particles. The proper expression is E^2 = (mc^2)^2 + |pc|^2 where p is the 3-momentum of the particle. If the particle is at rest p=0 and you get E=mc^2, if m=0 you get E=pc, as is the case for photons and gluons.

the theory of evolution as we know it was modelled on what had been physically observed and research into fossils etc. it has been developed as more evidence has been sought.

It's exactly the case for relativity.

 

[|Thomas|]

Actually that's not correct as it doesn't apply to massless particles. The proper expression is E^2 = (mc^2)^2 + |pc|^2 where p is the 3-momentum of the particle. If the particle is at rest p=0 and you get E=mc^2, if m=0 you get E=pc, as is the case for photons and gluons.

I know , it was purely intended as a joke that people quote E=MC^2 as some master equation for all things when it is purely a relation for rest mass energy, nothing else.

Besides, who needs these factors of c?

 

[BetaNumeric]

c=G=h=k=1
Any other units are flithy liars.

 

[|Thomas|]

c=G=h=k=1
Any other units are flithy liars.

It's posts like this that separate armchair physicists from real ones .

May I ask what is it you do? Are you doing a PhD? I ask because I'm currently looking at applying for theoretical particle physics PhDs and I'm just curious what your postgrad experiences have been like?

I hope we're not going too far off topic.

 

[Castiel]

Again, the results will come back, neutrinos will NOT be travelling faster than c. Sorry to spoil the party

that may well be the case, however it is very presumptive to dismiss people who clearly know their science and who while cautious are not so dismissive based purely on what we think we know.

Science has a nasty habit of disabusing people with such static and immutable positions.

 

[Castiel]

c=G=h=k=1
Any other units are flithy liars.

For us mathematical illiterates would you be so kind as to explain?

I can only assume that it refers to [speed of light]c=[Newtons Gravitational Constant]G=[Planck Constant]h=[Boltzmann Constant]k=1

However I have no idea what that means in lay mans terms.

 

[|Thomas|]

For us mathematical illiterates would you be so kind as to explain?

Theorists usually work in a system called natural units, where they define constants such as the speed of light, c, as 1. This massively simplifies equations such as E^2 = (pc)^2 + mc^2 to simply E^2 = p^2 + m^2, for example.

If you need to work out the final answer in SI units then you can just shove factors of c and other constants in at the end to make it work.

 

[Castiel]

Theorists usually work in a system called natural units, where they define constants such as the speed of light, c, as 1. This massively simplifies equations such as E^2 = (pc)^2 + mc^2 to simply E^2 = p^2 + m^2, for example.

If you need to work out the final answer in SI units then you can just shove factors of c and other constants in at the end to make it work.

Brilliant, just the laymans answer I was looking for. Thanks, now I understand.

 

[BetaNumeric]

For us mathematical illiterates would you be so kind as to explain?

In physics there's a bunch of constants which appear a lot, G for Newton's mavity constant, c for the speed of light, h for Planck's constant and k for Boltzmann's constant. Rather than have expressions like E^2 = (mc^2)^2 + |pc|^2 you say "I'm going to work in units of length, time, mass etc such that the speed of light is 1 unit of length per unit of time etc", then you end up with the much simpler E^2 = m^2 + |p|^2. In GR the Einstein field equations include factors of G/c^5 but it's much simpler to set G=1 and c=1 to get rid of them.

You can put them back at the end of your calculations by matching units. It's a way of simplying the algebra and every book on relativity and quantum mechanics will open with "We work in units where G=c=h=k=1".

It's posts like this that separate armchair physicists from real ones .

May I ask what is it you do? Are you doing a PhD? I ask because I'm currently looking at applying for theoretical particle physics PhDs and I'm just curious what your postgrad experiences have been like?

I did a maths degree + masters then a string theory PhD. I finished that April 2010 and got a job for a maths research company the following month, doing stuff like applying quantum mechanics to satellite design (really) or functional analysis to data processing.

Are you doing a maths degree or a physics one? Maths is generally more useful for theoretical physics. Mine was obviously quite abstract and unrelated to experiments. It's pretty good, provided you like what it is you're doing. My advice would be to make sure you either do a subject you love or your supervisor is brilliant. That way you can get through the years a bit better. If your supervisor is less than helpful and you're not in love with the topic you'll be likely to drop out or struggle. I was lucky that I'd always wanted to work on a particular thing (stablisation of compact dimensions in string theory) and a staff member did that sort of thing. They were a very bad supervisor, to both myself and the other student, but I got through it because I work by myself fairly well. Others in my year worked in groups a lot and got carried a bit by that, even though they weren't enjoying it. Basically, as with any PhD, if you are half arsed don't do it, you'll find yourself hating it.

 

[|Thomas|]

I did a maths degree + masters then a string theory PhD. I finished that April 2010 and got a job for a maths research company the following month, doing stuff like applying quantum mechanics to satellite design (really) or functional analysis to data processing.

Are you doing a maths degree or a physics one? Maths is generally more useful for theoretical physics. Mine was obviously quite abstract and unrelated to experiments. It's pretty good, provided you like what it is you're doing. My advice would be to make sure you either do a subject you love or your supervisor is brilliant. That way you can get through the years a bit better. If your supervisor is less than helpful and you're not in love with the topic you'll be likely to drop out or struggle. I was lucky that I'd always wanted to work on a particular thing (stablisation of compact dimensions in string theory) and a staff member did that sort of thing. They were a very bad supervisor, to both myself and the other student, but I got through it because I work by myself fairly well. Others in my year worked in groups a lot and got carried a bit by that, even though they weren't enjoying it. Basically, as with any PhD, if you are half arsed don't do it, you'll find yourself hating it.

Thanks for that .

At the moment I'm just about to start my 4th year undergrad in Physics. My project this year is more on supersymmetric phenomenology than hardcore theory and I'm hoping to stay in a similar sort of field for a PhD. I don't think I have the mathematical ability, or qualifications, to work on stuff like string theory or quantum loop mavity but that doesn't bother me so much .

Thanks for the advice though, I really want to pester my 4th year supervisor to see who he thinks is good in his field .

 

[DiCe!]

I am nothing but an arm chair bod, I would have loved to do physics at A level and then uni but i got a BC at GCSE and they wouldnt let me do it....wish I had studied harder! grrr

 

[ThePirateHulk]

Now the second point, I said that if you can send information Faster than Light then you break Causality. This means, that if you could send a signal (or matter, anything with "information") faster than light, via Lorentz transformations and other mathematics the signal you send could arrive back to you BEFORE you send the signal out!

Imagine the signal says "Don't send this signal". You never send it, and it never returns telling you to not send it... so you send it. This is causality. Breaking causality will ruin physics as we know it, and it should be unbreakable. How can the effect occurr before the cause?

Surely that is wrong. Regardless of the speed of the information the effect will never occur before the cause. The observation of the effect may occur before the observation of the cause but that is not time travel.

 

[Docaroo]

Surely that is wrong. Regardless of the speed of the information the effect will never occur before the cause. The observation of the effect may occur before the observation of the cause but that is not time travel.

I'm afraid not dude!! Please read this (I know it's heavy going, but you shouldn't comment again unless you actually read it):

http://www.theculture.org/rich/sharpblue/archives/000089.html

That shows how, via faster than light information travel you can send a signal that appears to arrive before it is send.

Observing an effect before the cause is certainly time travel!! It breaks causality.

By the passage of time as we see it, cause MUST ALWAYS come before effect. Always.

If this isn't the case, causality is broken and so is our understanding of the Unvierse. Having Effect before Cause just can't work, without accepting the "grandfather" paradox (basically the signal paradox that I mentioned).

The fact is, that if Faster Than Light information travel is possible (which this result would actually be saying), then if WOULD be possible to send a signal that would arrive at the source BEFORE that signal is sent, and thus you can create the paradox.

 

[mjs97]

Surely that is wrong. Regardless of the speed of the information the effect will never occur before the cause. The observation of the effect may occur before the observation of the cause but that is not time travel.

I had trouble figuring out how FTL equals time travel, until someone told me the following.

A good way to envision it is as follows:
Alice and Bob are to have a duel at 8 paces. They stand back to back, then each stride forth. This being a physics thing, they stride forth at a sizeable speed. Let's say they're both moving at a sizeable fraction of c. This means that thanks to relativity, time passes differently for them.

Suppose they're travelling at such a speed that each sees the other moving at only half normal speed. When Alice reaches 8, she turns and sees Bob is only at 4. She shoots him.

Now - as long as the bullets are travelling slower than c, by the time they reach him, he'll have reached 8, but if they can travel significantly faster than c, they could reach him while he's still at 4.

So Bob is walking along quite happily, but when he reaches 4, he feels a bullet go winging past, narrowly missing him. He turns, and sees Alice is still only at 2 (due to time dilation), and thinks she must have cheated, so he shoots her. If his bullets are as fast as hers are, then she gets shot at 2, before she's shot Bob.

I've no idea how it would look to an observer - confusing, I suspect...

 

[Robosapien]

bump

I can't see how traveling faster than c means time travel. It's a concept derived from setting c as the fundamental boundary to encapsulate all possible past events that could have a causal link to future events by assuming nothing can travel FTL - surely this new result just means we have potentially underestimated the limiting speed in nature. Anything traveling FTL (partially) invalidates the theory, therefore using the same theory to make claims of time travel is absurd.

c is often approximated to 3x10^8, does this new result make any real difference to observations confirming the relativity theories?

I find the idea of taking short-cuts through 'tiny curled up dimensions' an irritating one, is there any experimental proof at all for string theories? Mathematics exists in it's own world after all and we're only using a fraction of it as a tool only to describe the physical world where there is a convenient overlap between the two (and how we perceive both).

 

[Docaroo]

I find the idea of taking short-cuts through 'tiny curled up dimensions' an irritating one, is there any experimental proof at all for string theories?

Well... this result might actually be that very proof!

Again, please read this (third time posted in this thread!):

http://www.theculture.org/rich/sharpblue/archives/000089.html

If you read it you will surely be able to see how sending information faster than light speed can make that information break causality (it can arrive before it is sent). It depends on the frame of reference in spacetime.

There are three things that currently hold true:

1. No information can be send Faster than Light (that includes mass)
2. Causality is strictly adhered to, Cause must also occur before Effect
3. Special Relativity is a robust description of the our observable universe

If you break the first point, then either point 2 or point 3 are invalid!!

Point 2 being invalid would surely destroy everything we know about physics and the Universe.

Point 3 doesn't appear to be invalid because it's been so thoroughly tested by experiment and observation!

So, I believe Point 1 must also hold true, and that we must look to another explanation for the results.

 

[Docaroo]

Should have said... String Theory does actually have a valid explanation for why neutrinos can do this.

If they "flip" into the fourth postulated type of neutrino (a sterile neutrino) then in string theory this neutrino can tunnel through the bulk (we sit on the brane) in string theory terms and take a shortcut through it.