Slashdot Mirror
Gamma Ray Anomaly Could Test String Theory
exploder writes "String theory is notorious for its lack of testable predictions. But if the MAGIC gamma-ray telescope team's interpretation is correct, then a delay in the arrival of higher-energy gamma rays could point to a breakdown of relativity theory. A type of 'quantum lensing effect' is postulated to cause the delay, which is approximately four minutes over a half-billion year journey." Ars's writeup is a little more fleshed-out than the Scientific American blog posting.
From the page...
/.'ed, I don't know what is :)
Update (August 24th): We're starting to see bloggers weigh in, including the inimitable Lubos Motl and Chris Lee at Ars Technica, though I'm surprised there's not more. Here we finally get some observations that probe string theory, if only tentatively, and people who have been loudly complaining about the lack of such observations have gone silent.
Wow - if that's not a dare to be
Wouldn't it suck to have to reboot during that 4.5 min? Oh crap, guys go home I'll see you in a few billion.
While this is great research, even if it can be demonstrated that the higher energy particles traveled faster, this is not a prediction specific to String Theories, but as the arstechnica.com article points out, this is common to most quantum gravity theories. Still, it would be an awesome thing to prove.
the ars article says 3-4 seconds, not minutes
Did you know that "FTW" ("for the win") is a direct translation of "Sieg Heil"?
Ars's writeup is a little more fleshed-out than the Scientific American blog posting.
I stopped reading Scientific American for the same reason I don't read USA Today. Because reading it is the same as not reading it.
Now I read American Scientist.
But who am I to argue with quantum mechanics.
~Sticky
There is no need to confirm a breakdown of relativity. We already know that it is, at the least, incomplete, if not incorrect. Albert Einstein himself saw this, and was on his own quest for a "theory of everything" in his later years. String theory should become fully "testable" with the startup of the LHC (Large Hadron Collider, part of CERN) in May of 2008. Hopefully we may find proof for the God particle, also known as the Higgs boson. In any case, tremendous amounts of data will be reaped from this machine, and we may very well prove or at least expand upon string theory. (We could also completely disprove it, but I'm trying to be optimistic.)
I do know everything, just not all at once. It's a virtual memory problem.
If the standard model fails, string theorists will laugh, jump and down, and point their fingers at their former naysayers.
If the string theory model fails, it will be replaced with a newer, better version of string theory, with bountiful opportunities for new books, conferences, papers, and maybe even some derivative specialities of study.
YOU CAN'T KILL WHAT LIVES ONLY THE MINDS OF MEN... BUWAHAHAHAHAAAAA!
When things get complex, multiply by the complex conjugate.
Wrong. You just kill all the men with the minds.
Nothing can stop Hulk from Smashing string theory to bits. Hulk will destroy puny humans who betrayed him. Wait, that's a Skrull. Is nobody a human anymore?
There is a need to confirm a breakdown of relativity. It's an incredibly well-supported theory that predicts things on cosmic scales down to the Hydrogen atom.
The Higgs boson is predicted by the Standard Model, not String theory. String theory will be no more testable with LHC than it ever was. It's not even wrong.
I'm afraid that the standard model failing wouldn't help string theory, you can't prove your own theory by disproving the other one. Theories are sadly not like detective games, where there are only so many options and if you just eliminate the other ones yours must be true, sadly they can be all wrong in science.
The research looks legit, but the Slashdot tagline does not. The existence of such phenomenon does not appear to favor Superstring hypotheses any more than it supports a number of other hypotheses that are currently under investigation. ("Hypotheses", because they have not yet earned the name "theory" via prediction or testability.)
Perhaps this will help sort things out, and even boost one or more of these ideas into actual theory status. Until then, it is premature to imply that this research constitutes evidence for "string theory" more than it is evidence for any of those other hypotheses. This is evidence for quantum gravity, but not yet for anything else.
The problem is not with finding a way to prove string theory so much as find a way to falsify it. There are many ways to prove string theory, but seemingly no way to falsify it. Because every failed prediction it has made so far has been alright because both the failure and success have been within the realm of possibility of the theory. This is why I'm not a huge fan of string theory and generally feel that it is more akin to religion than science. But, then again, I'm not a physicist. So, what do I know? (not very much is the answer)
IAAA [I am an astrophysicist], and I'd like to point out what I feel is an important caveat to this nevertheless very interesting work. From the paper itself:
"We cannot exclude the possibility that the delay we find [...] may be due to some energy-dependent effect at the source."
What they are saying is that there are still details we don't understand about AGN [active galactic nuclei] like Markarian 501. So, while this effect could be a first sign of quantum gravity (*not* string theory in particular, as others have pointed out), it could also simply be something going on in the intrinsic spectrum of the flares themselves. I'd personally consider the second explanation more likely at this stage.
As they also point out, one approach to sort out the ambiguity would be to observe other flary AGN at different redshifts (distances). One could then, for example, see if the delay gets shorter or longer as the distance changes, as one would expect with a quantum gravity effect due to propagation to Earth.
This is exactly how I feel about relativity in general. I believe that yes, it passes every test we can throw at it right now, but one day it'll be shown that it's just plain silly. I don't have a better idea but do not prescribe to relativity.
(Time dilation due to speed? Pft hardly. Maybe there are subatomic particles such as electronics whose movement becomes dampened when approach speed because they have a fixed absolute speed, or even slow downs at the quantum level [maybe], but that doesn't mean time actually moves at a different speed. It just means that below our current ability to understand things are working more slowly so everything that we do understand seems be slower. Time warp? I think not.) Oh egocentric humans amuse me.
Isn't it also egocentric to assume upfront that you have the correct answer and all those other folks who worked on it all there life are a bunch of fools?
PS I just remembered, your idea of an underlying mechanism was a common idea for a long idea for many scientists including Einstein, it is just that every experiment conceived by them proved them wrong and showed that it was exactly as the theory portrayed. So I wouldn't bet on your idea of how things work to be so certain.
The simplest explanation is most likely to be true. Here's a hypothetical that's simpler than any quantum effect.
The gamma rays are due to infalling material. Flares are due to sudden large amounts of material falling in. As it falls in it gets hotter. The frequency of the emissions increases as the material heats, going from lower gamma rays to higher gamma rays. These are all accepted as fact. The hypothetical: The 4 minute delay is the time it took for the material to fall in far enough to raise the emission frequency by the observed amount.
Much simpler and neater. Even if I had the observed data and the data on the mass of the galaxy observed, I'm not capable of the relevant calculations, but the logic follows.
On the other hand, Willam of Ockam didn't have a razor -- he had a beard. Einstein trumped Newton with a more complex theory, so the parsimony beloved by scientists doesn't always hold. But in this case, I suspect it will.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
Could someone explain to me a single phenomenon that is explained by string theory? Or a single predictive theorem, where thanx to string theory we expect to find x if conditions y are met? I need to know what I'm even looking for here.
http://xkcd.com/171/
can be found here:
http://xxx.soton.ac.uk/abs/hep-th/0501117
String theory doesn't really exist anymore or at least it is old news. String theory turned into superstring theory. Then there came to be multiple string theories that were very similar. About a decade ago Edward Witten created M theory by reconciling the 5 string theory variations that existed. Maybe I'm wrong but my view is that M theory is the leading edge. I just got done reading Brian Greene's The Fabric of the Cosmos so it is pretty fresh in my mind but Wikipedia helped me remember a few things just now.
this nation, under God, shall have a new birth of freedom. -- Lincoln, Gettysburg Address
I think you're talking about special relativity, not general relativity, and that you have never studied it in more depth than at a lay man level. The whole point of special relativity is that time is just another dimension in addition to the three space dimensions we already have, and that you need to use the correct coordinate transformation if you switch to a different basis set. If you express a point (x,y) in terms of axes that are at 45 deg angles with the original x and y axes, you end up with sqrt(0.5)*(x+y, x-y) in the new coordinate system, coupling the x and y coordinates with each other. In special relativity, there is a similar transformation when one coordinate system moves w.r.t. the other one. Rather than coupling just x with y, it couples all of x, y, z, and time. Now indeed this leads to counter-intuitive effects for humans that aren't used to moving at close to the speed of light, which you might describe as "time dilation" when you try to map the observations to the concepts of our non-relativistic everyday world. An example of why time dilation is not the right way to look at it is the case that one observer is standing at a fixed position, while the other one is moving. Both of them will think the time of the other observer is dilated, while their own time is normal. You can't point out for which of the two observers the time is dilated, simply because the concept of time dilation is inconsistent. (However, when one of the observers turns around and comes back, his clock will appear to be behind, but that has to do with the change in speed he underwent when turning around, not the speed on its own. Speed changes, i.e., acceleration, are described in general relativity, not in special relativity).
A better theory will probably be developed at some time. But that will not degrade the current, established relativity theory to be "plain silly", just like Newton's laws didn't become silly after the development of quantum mechanics and relativity. The equations for the unified theory would look just like those of relativity if the length scale isn't too small, just like classical mechanics if in addition the energy is small, and just like quantum mechanics if both the length scale and energy are small. Physics is about describing nature quantitatively, not about attaching a deeper meaning to it or answering the question "why" nature is the way it is.
Avantslash: low-bandwidth mobile slashdot.
What if you kill all the men?
Modern copyright is theft of culture from everyone and it retards the progress of the useful arts and sciences.
How do you kill what which has no life?
If you kill a sand worm, it will only shatter into many sand trout to form other worms.
weird interaction with noscript.
How do you kill what which has no life?
If you kill a sand worm, it will only shatter into many sand trout to form other worms.
By itself variable speed of photons does not violate relativity. Suppose one day experiments would have shown that photons had a mass, like neutrinos. Then photons would not travel exactly the limit speed C. Relativity relies on this limit speed, not on the actual speed of photons. Electromagnetism does use C as speed of light. But then again, who expects such level of precision from a classical theory.
Allright, but I wouldn't have taken the the time to write such a long reply to the grandparent who is obviously a n00b thinking he is on the same IQ scale as the theorists.
IMHO, the grandparent was just pointing out that string theory has morphed as necessary to prevent itself from being discarded. M theory is just the latest attempt, but when it loses steam, string theorists will jump on the next "variant" to keep producing the "books, conferences, papers, and maybe even some derivative specialties of study" mentioned by the grandparent, of which Brian Greene's book is an excellent example.
First of all, this observation is FAR more likely to be due to variations at the source (which may have simply emitted the high-energy photons a little later than the low energy ones) then to some huge new discovery.
Second, if this really is due to fundamental physics, it's a violation of Lorentz invariance (special relativity) and it would be about the best possible *disconfirmation* of string theory you could ask for (IAAST). If there's one basic prediction of string theory, it's Lorentz invariance (the Ellis-Nanopolous stuff is, in just about every other physicist's opinion, nonsense).
But it goes much further than string theory. Lorentz invariance is something physicists - not just string theorists - are almost certain is true, and for good reason. It's been extremely well-tested in many different ways over the years and just about all our modern theories rely on it to constrain what might be possible. Without Lorentz invariance, the rules of the game shift fundamentally, so if this observation turns out to mean it isn't exact it's very, very important.
Bravo!
Anyone else annoyed by the blog's use of, "Either the high-energy gammas were released later (because of how they were generated) or they propagated more slowly?"
It's always difficult to talk about propagation. It would seem that the only information we have is that the high-energy gamma rays traversed the net distance 'tween us and this galaxy more slowly.
One possibility, then, is that they took two different paths. There are a number of mechanisms which could result in this, although (off the top of my head) most of these could not be duplicated easily. Additional observations need to be made.
String Theory ST) has been tested as thoroughly as the Standard Model (SM). It's an alternative model, and physics presents mathematical models of the world. The models aren't the world. Insofar as String Theory predicts the same things as the Standard Model, it is just as tested as the Standard Model. All this talk of "untested String Theory" misses the point. It is very difficult to create tests that distinguish ST from the SM. But the observations predicted by each have been throughly tested because their predictions are very nearly the same. Scientists are failing to distinguish between observations that validate the models and observations the distinguish the models. It may turn out that there are no distinguishing observations, in which case ST and SM would be equivalent models. Why does that prospect make physicists act like Creationists, calling ST "untested"? Some physicists balk at branes, but accept the existence of forces which have never been observed either! It's another example of slouching fundamentalism in science, caused by a lack of understanding (or an outright rejection) of model theory among physicists. Note to physicists: your math is a model, it 'aint the real world.
Society is nothing but collaboration.
This could also mean the distance of the galaxy (and other objects) has been mistaken based on misconceptions of light. The distance is calculated with photons, but if the gamma ray follows a non-standard speed, who's to say the photons are going the right speed?
I am NOT a number! I am a - oh wait, I'm number 761710. Look! 761710!
Hello:
/. nerd, I do have my own unified field theory which has several testable hypotheses. It is 4D, I've got the action, field equations, and exponential metric solution for a point source. A discussion of the idea happened here:- gem-rank-1-unified-field-proposal.html
Like a good
http://www.bautforum.com/against-mainstream/61876
One test is to measure bending of light to second order PPN accuracy, basically a million times more than was needed to tell the difference between GR and Newton. Do that for GR, and there should be 10.96 microarcseconds more bending. For my GEM proposal, it should be 11.69, a difference of 0.73 microarcseconds. We can only make measurements to 100 microarcseconds today, bummer.
GEM also predicts that gravity waves should be the scalar and longitudinal modes of emission, since the transverse modes of emission are light. Cannot wait for those gravity waves to be detected!
I am pretty sure gravity is not going to mess with the speed of light in my proposal, where the vacuum state is linear, in gravity as in EM. In the GEM action, gravity lives in a second rank symmetric field strength tensor, and EM lives in a second rank antisymmetric tensor. The separate housing arrangements make sense since one is a spin 2 field, the other spin 1.
I hope it is the source.
doug
Working on new views of old physics at http://VisualPhysics.org
... by lolcats. here. kthnxby
I don't have an idea of how things work, I just wish people would stop putting so much stock on whatever the belief of the day is.
We all know that Einstein space time is not euclidean. So if there is outward expansion from what we believe to be the big bang, which only moments before was a singularity, why is space time curved. Perhaps higher energies are closer to being mass, because they have more energy. Why can't we reverse E=MC2 and produce mass from energy, perhaps this could be source of dark matter. According to Einstein, more energy is required than is in the universe to accelerate a particle that is going less than the speed of light and accelerate it up to that speed. What about if this also correlates into energy moving slower when it is involved and binding itself into some amount of mass. Gravity has an effect on light because it has some mass. Surely the mass amongst a great number of particles moving in a wave could be bound together when some of the particles which are of extreme amongst group are of such high energies that they become a particle theorised as needed by some theorists to hold eneregy in place. The creation of this mass brings about the possibility for gravity on a much far larger scale then plain energy floating around every could. At points where space-time is being curved to a greater extent than others then any particle has much further to travel.
/____________________ \
/ ------------ \
The bottom line although effected by gravity is a shorter distance to travel than the top on which now has it's own mass acting on itself. Does time stop when the temperature reaches absolute zero (How can you have mass without energy, it's very definition says it has energy, subatomic particles don't just sit there doing nothing.?
Not all conservatives are stupid,
but it is true that most stupid people are conservative.
- Hume
This results follows from Aether Wave Theory, which has predicted it before year.& st=180
u ation/wavcvslength.gif
http://forum.physorg.com/index.php?showtopic=9309
The normal dispersion is the classical phenomena in multiparticle systems, where transversal wave prevails.
http://superstruny.aspweb.cz/images/fyzika/waveeq
Concerning the other theories, no cusual theory based on the special relativity postulates (most of QFT, including the string theories) can predict the opposite by rigorous way
I never argue with Quantum Mechanics unless I'm at least a 13 level Wizard with plenty of HP, in which case I eat their corpse in the hope of getting speed as an intrinsic.
But that's just me.
It take more faith to believe in evolution than it takes to believe in God