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Test for String Theory Developed

samzenpus posted more than 8 years ago | from the new-dimensions dept.

155

inexion writes "PhyOrg is reporting that SLAC (Stanford Linear Accelerator Center) scientists have found a way to test the revolutionary theory, which posits that there are 10 or 11 dimensions in our universe. This past December, Joanne Hewett, Thomas Rizzo, and student Ben Lillie published an article in Physical Review Letters which shows theoretically how to measure the number of dimensions that comprise the universe. By determining how many dimensions exist, Hewett and Rizzo hope to either confirm or repudiate string theory under specific conditions which would consist of creating and examining 'micro-black holes', which could be formed by smashing two high energy protons together. Using the predicted decay properties of the emitted neutrinos, Hewett and Rizzo solved equations to find that our universe may have more than 10 or 11 dimensions -- too many dimensions to be explained by string theory."

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155 comments

A Lot of 'Theoreticals' (5, Interesting)

eldavojohn (898314) | more than 8 years ago | (#14674708)

How many micro-black holes have we measured in a lab?

None.

How many micro-black holes have we even seen?

None, as it turns out [wikipedia.org].

This is a story of hope and speculation--much like the story of super string theory.

Hell, do we even have the capabilities to smash two high energy protons together?

To be fair, Bosonic Super string theory has room for 25 [wikipedia.org] dimensions but it's flawed with tachyon, the so called imaginary mass.

I'd be interested to know how they intend to measure the micro-black holes.

Re:A Lot of 'Theoreticals' (5, Informative)

kebes (861706) | more than 8 years ago | (#14674747)

Hell, do we even have the capabilities to smash two high energy protons together?

Well particle accelerators have been smashing high-energy protons together for a long time... but can we smash them hard enough to create micro-black-holes? No. ... not yet, anyways. But that's why the Large Hadron Collider [web.cern.ch] is being built! This is the frontier of particle physics.

I'd be interested to know how they intend to measure the micro-black holes.

The LHC has been in the works for a long time, and should come online sometime in 2007. This instrument will be able to probe these questions, and set limits on the possibility of micro-black hole production, as well as extra dimensions.

Re:A Lot of 'Theoreticals' (1)

sarragorn (654091) | more than 8 years ago | (#14676135)

All this is old news It's a different spin but it's the same old "we hope out next gen particle accelerators can prove our theory" Can't you see that ever since 1 month ago when someone reposted some biased article which linked to string theory, news has started to flow on this subject. But the same old spin, nothing new. i think this is politics mainly science politics

Re:A Lot of 'Theoreticals' (1)

gd2shoe (747932) | more than 8 years ago | (#14674750)

"If scientists were to smash two high energy protons together they could theoretically make such a micro-black hole. This particle decays quickly and emits over a dozen different kinds of particles such as electrons, neutrinos and photons which are easy to detect."

They hope they decay quickly.
Bear in mind that all they have to work with right now is theory.

Anyone else here read "Thrice upon a time" ?

Re:A Lot of 'Theoreticals' (1)

gd2shoe (747932) | more than 8 years ago | (#14674766)

Before anybody comes along and rants on me, Yes, I know the odds are that the profesionals know what they are doing. It still leaves room for speculation...

Re:A Lot of 'Theoreticals' (1)

vertinox (846076) | more than 8 years ago | (#14674786)

I'd be interested to know how they intend to measure the micro-black holes.

I dunno... Is this kind of treading on the "igniting the atmosphere" kind of problem with A-bombs.

I mean if make a mini-black hole and drop it on the floor by acident, wouldn't it just absorb more and more mass on the way to the center of the earth.

I know... I know... You can't "drop" a black hole on the floor... But if you could wouldn't it be neat ;)

My God! It's Ed Wood! (4, Funny)

eldavojohn (898314) | more than 8 years ago | (#14674809)

I mean if make a mini-black hole and drop it on the floor by acident, wouldn't it just absorb more and more mass on the way to the center of the earth.
I didn't know Ed Wood developed plot lines on Slashdot.

The universe is safe. (5, Informative)

kebes (861706) | more than 8 years ago | (#14674843)

All black holes emit Hawking radiation [wikipedia.org], which is essentially black-body radiation [wikipedia.org] (the object is trying to come into thermal equilibrium with the rest of the universe, so is emitting/absorbing radiation to do so). The origin of Hawking radiation is vacuum pair production [wikipedia.org], if anyone is interested. This radiation causes the black-hole to slowly "evaporate." The temperature (hence rate of evaporation) is inversely proportional to the black-hole mass (hence size).

Micro-black-holes are (obviously) very small. Thus, they evaporate very, very quickly. In fact, they are well below the sustainable threshold, and will evaporate much faster than they accumulate new mass. Also note that these micro-black-holes have quite low mass, hence their graviational attraction is pretty much nill. They are "black holes" because their mass density is infinite, and they are thus a singularity, but nothing about "black holes" definitely implies "consumes matter indefinitely" (this only happens for black holes of sufficient size).

So, no, there is no danger with micro-black-holes eating up the entire Earth. Yes, our current theories may be incorrent (you never know), but if micro-black-holes were able to grow without bound, then you'd expect the universe to be littered with black holes all over the place (which is not the case). Thus there's no reason to worry: the LHC will not gobble up the Earth.

Phew!! (1)

Nikker (749551) | more than 8 years ago | (#14675036)

So, no, there is no danger with micro-black-holes eating up the entire Earth

Man I'm glad I read this as a /. post I was really worried there for a second....

Re:The universe is safe. (2, Interesting)

blamanj (253811) | more than 8 years ago | (#14675254)

Slightly off-topic question. Does vacuum pair production have anything to do with inflation? I've never understood what drives the rapid expansion right after the big bang.

Re:The universe is ... what? (2, Funny)

Anonymous Coward | more than 8 years ago | (#14675297)

Yes, our current theories may be incorrent (you never know), but if micro-black-holes were able to grow without bound, then you'd expect the universe to be littered with black holes all over the place (which is not the case).

Yeah, there's nothing wrong with guestimated probability, or an understanding of the universe based on an uneducated perception. Hell, what's the worst that could happen, anyway? Tho', who among us would recognize a micro-black-hole if we saw one ...?

Oh, well. I hereby declare micro-singularities safe! As far as we know. Er, have observed. Which isn't much. At all, really. So ... um ... good luck.

Boom.

(Incidentally, I "expect" this post to merrily go completely unnoticed and acquire a total score of 0.)

Re:The universe is safe. (1)

cheekymatt (175255) | more than 8 years ago | (#14675327)

>>if micro-black-holes were able to grow without bound, then you'd expect the universe to be littered with black holes all over the place

Of course, we also don't have Large Hadron Colliders all over the universe, smashing particles together with enormous speed and accuracy, do we?

Re:The universe is safe. (2, Informative)

qeveren (318805) | more than 8 years ago | (#14675400)

The energies of naturally-occurring cosmic rays far exceed those of our most powerful accelerator experiments on a routine basis. Anything we do in a particle collision experiment has already happened uncounted times in nature.

Re:The universe is safe. (4, Interesting)

ArbitraryConstant (763964) | more than 8 years ago | (#14675481)

"Of course, we also don't have Large Hadron Colliders all over the universe, smashing particles together with enormous speed and accuracy, do we?"

The universe can easily put our best efforts to shame. For example, the Oh My God particle [fourmilab.ch]. If constant bombardment by these sorts of particles hasn't yet destroyed us, it's doubtful anything we do will make it worse.

Re:The universe is safe. (1)

mako1138 (837520) | more than 8 years ago | (#14675344)

I'll add that according to current theory, extremely high energy cosmic rays create mini black holes all the time. We've seen these extreme cosmic rays, and we haven't been swallowed up yet, so it's reasonable to conclude that the danger is nonexistent.

Re:The universe is safe. (2, Informative)

Ruie (30480) | more than 8 years ago | (#14675390)

In addition one should not forget that Earth atmosphere gets routinely bombarded by cosmic rays - some of which are very fast protons, much faster than what we can create in the best colliders.

So if there was a way to create an indefinitely growing black hole with particle collisions this would have happened over the millions of years that Earth has been around.

Re:The universe is safe. (0)

Anonymous Coward | more than 8 years ago | (#14675695)

there is no danger with micro-black-holes eating up the entire Earth.

If they do, I'm blaming you!

Re:The universe is safe. (1)

Memnos (937795) | more than 8 years ago | (#14675740)

I agree with everything you posted, except that we do not know that any black holes are singularities, even of the Kerr-Newman type. We are pretty sure that they have an event horizon, but what's beyond that has not been empirically verified.

Re:A Lot of 'Theoreticals' (2, Interesting)

Jerf (17166) | more than 8 years ago | (#14675419)

What ultimately put my mind at ease with regard to all of these "what ifs" is the recognition that cosmic rays routinely smash into the Earth with energies that we can still only dream of; for instance, see the Oh-My-God particle [fourmilab.ch], an impact event still several orders of magnitude in energy above what we can produce in a lab. If an impact event could produce a black hole that could swallow a planet, the Solar System and indeed the entire universe would be nothing but a bunch of black holes of various sizes orbiting each other, as every massive body has long since been hit with at least one particle sufficient to start the black-hole or strangelet putative chain reaction.

Seeing as how every massive body in the universe has been hit with umpteen bajillion of these impacts, yet massive bodies remain, it would seem the probability of this occurring is effectively 0.

A priori, it's not necessarily a wrong idea. But the evidence is pretty clear that it's not a problem.

Re:A Lot of 'Theoreticals' (1)

m0rph3us0 (549631) | more than 8 years ago | (#14675430)

Small black holes actually evaporate due to Hawkings radiation. So they generally dissapear before swallowing the galaxy. Interestingly enough, the black hole at the centre of our galaxy would float on water given its average density.

Re:A Lot of 'Theoreticals' (1)

Memnos (937795) | more than 8 years ago | (#14675708)

No, no, no. The kind of black hole created by a particle accelerator would decay so quickly via Hawking radiation that we would be lucky to see the tracks and even know that it was "there". It would be far too small to absorb mass/energy faster than it lost it. Such micro-black holes may indeed have already been created by the RHIC in Brookhaven. It's late and I am tired, but IAANP.

Layman's explanation (1)

yoprst (944706) | more than 8 years ago | (#14675913)

Layman's explanation: the blackhole as you imagine it is giant mass that sucks things in and don't let them out. The side effect of such nasty behaviour is some ugly physics taking place inside. When you hear about small black holes, you imagine the same kind of horror, just very small. In fact, the small bastards have almost no mass, don't suck in anything _at all_, they just have the same ugly physics scientists are interested in. To put it short, in layman's words - it's not a black hole at all.

Re:A Lot of 'Theoreticals' (1)

Jugalator (259273) | more than 8 years ago | (#14675620)

How many micro-black holes have we measured in a lab?

None.


I agree about the string theory being, well, just a theory at this stage, but this isn't a sign they aren't there, it's just because we haven't had equipment good enough to experiment at this tiny scale before.

This statement is similar to how one today can say "how many Earth's have we seen? Not many, it's mostly Jupiter's out there". Of course, that's right, but it doesn't actually mean anything, as we haven't had good equipment to detect Earth-sized exoplanets in the first place.

CERN's Large Hadron Collider, that will look for this according to the article, will be operational in 2007.

Quantum "Nut Shot"... 'nuff said (0)

Anonymous Coward | more than 8 years ago | (#14675679)

Hell, do we even have the capabilities to smash two high energy protons together?
Hell, it's just the quantum version of the "nut shot", how hard can it be?

The actual scientific paper... (4, Informative)

kebes (861706) | more than 8 years ago | (#14674709)

The reference for the actual scientific paper in question appears to be:
"Black Holes in Many Dimensions at the CERN Large Hadron Collider: Testing Critical String Theory" JoAnne L. Hewett, Ben Lillie, and Thomas G. Rizzo Phys. Rev. Lett. 95, 261603 (2005) .

For those with access to PRL, the doi for the paper is: 10.1103/PhysRevLett.95.261603 [doi.org]

This is the abstract:
We consider black hole production at the CERN Large Hadron Collider (LHC) in a generic scenario with many extra dimensions where the standard model fields are confined to a brane. With ~20 dimensions the hierarchy problem is shown to be naturally solved without the need for large compactification radii. We find that in such a scenario the properties of black holes can be used to determine the number of extra dimensions, n. In particular, we demonstrate that measurements of the decay distributions of such black holes at the LHC can determine if n is significantly larger than 6 or 7 with high confidence and thus can probe one of the critical properties of string theory compactifications.
For those without access to PRL, you can view a different version of the manuscript on arXiv. [arxiv.org]

My comments (with the usual disclaimer: while I am a scientist, I'm not a particle physicist/string theorist, so I would appreciate any corrections to what I say): This work appears significant. String theory is incredibly elegant and fits in very well with other (experimentally verified) theories (quantum field theory, etc.). However, what string theory has always lacked, is experimental backup. The fact that there may be a way to experimentally test one of its predictions/requirements (that of extra dimensions) is truly significant, and will allow these fundamental theories to be advanced way beyond their current speculative nature.

As I understand it, one of the current "problems" in string theory is an over-abundance of theories. There are millions (perhaps even an infinite number) of theory-variants that are all consistent with the current string-theory formalism. Of course only one (or possibly zero) of the theories is right. An experimental test would (I hope!) help pick out which theory variant is the right one... or perhaps tell us that string theory is completely wrong! Either way it's a good thing for science and I look forward to this test being performed at the LHC.

Re:The actual scientific paper... (1)

pete-classic (75983) | more than 8 years ago | (#14674728)

If this can reduce the infinite field of possible theories by half then we will have made real progress.

-Peter

PS: I'm bad at Math.

Re:The actual scientific paper... (0)

Anonymous Coward | more than 8 years ago | (#14674829)

If you're working with infinity your progress cannot be real. It can only be imaginary.

Re:The actual scientific paper... (1)

PaulBu (473180) | more than 8 years ago | (#14674870)

There are millions (perhaps even an infinite number) of theory-variants...

But is this infinite number countable -- or is it continuous? ;-) Big difference, you know...

Paul B.

Re:The actual scientific paper... (1)

S3D (745318) | more than 8 years ago | (#14675628)

But is this infinite number countable -- or is it continuous? ;-) Big difference, you know...
it's a finite number, some researchers estimated it around 10^^240

Re:The actual scientific paper... (1)

aminorex (141494) | more than 8 years ago | (#14675768)

What is this ^^ notation? Exponentiate me harder? Double winky? I'm confused. (Again.)

Re:The actual scientific paper... (1)

blackcoot (124938) | more than 8 years ago | (#14674910)

i believe that witten showed two classes of these theories to be equivalent. as i recall, it's an open question as to whether all classes are equivalent. kind of the physicist's version of the P?=NP problem as i recall (i am most certainly not a physicist, so feel free to take anything i say with a suitably large grain of salt)

Re:The actual scientific paper... (4, Interesting)

davidoff404 (764733) | more than 8 years ago | (#14675038)

String theory is many, many things, but elegant it is not. Furthermore, it doesn't fit in well with other theories simply because we can't get a prediction out of the damn thing.

This paper is fluff. I read it when it first came out last March and I disagree strongly with the 5 sigma estimate in the test case they describe.

And yes, IAAStringTheorist.

Re:The actual scientific paper... (1)

yoprst (944706) | more than 8 years ago | (#14675936)

It sounds like being a string theoryst is worse than developing a death-march-style software...

Re:The actual scientific paper... (1)

KonoWatakushi (910213) | more than 8 years ago | (#14676179)

From what I have read, string theory seems very elegant; we simply lack the math to deal with it in a useful way. That is no fault of string theory, merely a hint that the we need to further our understanding, or that the universe is simply not conducive to modeling in such a naive fashion.

Re:The actual scientific paper... (4, Interesting)

bcrowell (177657) | more than 8 years ago | (#14675083)

From a brief perusal of the paper, it looks to me like:
  1. It's talking about highly hypothetical experiments that they imagine could be done at the energies the LHC can reach, not experiments that have actually been done.
  2. It's talking about tests of an unusual version of string theory, in which the extra dimensions aren't curled up as tightly as the Planck scale, and string theory starts to show effects at energies on the order of 1 TeV.
  3. They say the experiment could only disprove string theory, not prove it, and then only if the production of microscopic black holes occurred.
This all seems pretty unexciting to me as a nonspecialist. I mean, heck, if the LHC starts producing microscopic black holes, then obviously quantum gravity becomes a much more reasonable thing to work on, regardless of whether string theory is right or wrong.

In addition to string theory's problems with non-uniqueness you refer to, it seems to me that there's also a problem with string theory as a theory of quantum gravity, because it assumes a smooth background spacetime with the 3+1 ordinary dimensions being flat. But that's just not a reasonable way for a theory of quantum gravity to work. In particular, there are strong model-independent reasons [wikipedia.org] for believing that spacetime must be discrete, not continuous, at the Planck scale. So even if string theory could have all its other problems taken care of, it would still not be a good candidate for a fundamental theory of quantum gravity.

Re:The actual scientific paper... (1)

19061969 (939279) | more than 8 years ago | (#14676121)

"They say the experiment could only disprove string theory, not prove it, and then only if the production of microscopic black holes occurred."

Isn't this the basis of the scientific method ie, to disprove? Proving is impossible for science - we can only test a theory and not reject it for the time being. Consider Hume's "All swans are white" statement: it cannot be proved for certain that all swans are white because that would require examination of every swan that ever existed (even those that existed millennia ago) which is impossible. Disproving it would only require evidence of a non-white swan to falsify the theory.

As far as I can see, a falsifying experiment is good scientific work. Theories are there to be knocked down and subsequently modified in the light of new evidence. I think proof belongs in theology, maths, philosophy, or law.

Re:The actual scientific paper... (1)

wjsteele (255130) | more than 8 years ago | (#14676187)

I am not a scientest either, however, I thought all String Theories relied on a 10 dimensional universe... m-Theory (m = Magical, Miracle, but most scientests thing it is m=Membrane) is the one that had 11 dimensions. And when they went back an checked, all the different String Theories actually fit it's model.

Bill

I'd really like to see string theory .... (1)

DoraLives (622001) | more than 8 years ago | (#14674714)

turn into something a bit more substantial than what it is right now, but golly gee whiz, what happens if the the mini black holes don't behave quite exactly like they're supposed to?

Re: I'd really like to see string theory .... (4, Funny)

Black Parrot (19622) | more than 8 years ago | (#14674733)

> but golly gee whiz, what happens if the the mini black holes don't behave quite exactly like they're supposed to?

Given 11 dimensions to work with, it will be easier to kiss your ass good-bye.

I'd really like to see that. (1)

twitter (104583) | more than 8 years ago | (#14675021)

Given 11 dimensions to work with, it will be easier to kiss your ass good-bye.

Given 11 dimensions, you will be able to kiss everyone good bye, at the same time, without knowing it.

Re:I'd really like to see that. (1)

saskboy (600063) | more than 8 years ago | (#14675219)

Given 11 dimensions, what's the average Slashdotter's excuse for not having at least one girlfriend by now?

Re:I'd really like to see that. (1, Funny)

Anonymous Coward | more than 8 years ago | (#14675465)

Given 11 dimensions, how many one-liners can we post successively starting with "given 11 dimensions...?"

It depends upon what the definition of a theory is (2, Insightful)

jm92956n (758515) | more than 8 years ago | (#14674722)

I'm confused.

Evolutionary "theory," for example, has a substantial quantity of data that suggests the general notion is true. But string theory, at least in the scientific community, does not maintain the same support that most other "theories" have. There are, rather, a number of prominent physisists who believe string "theory" doesn't deserve the theoretical status it has obtained (or at least that's what I've been led to believe).

The question I have, therefore, how was the "theory" part conferred?

Re:It depends upon what the definition of a theory (1)

Muchacho_Gasolino (868337) | more than 8 years ago | (#14674785)

isnt anything that is purported to be true as a result of some a mathematical proof a theorem and something that is known to be true but has no proof a postulate(Law)? I would expect it to work in somewhat the same way in physics. a paper demonstrating some sort of reasonable explanation of why establishes a theorem. whether or not that logical proof is sound is another matter. and for something which is difficult to prove experimentally, like string theory and (some would argue)evolution, there is always debate. Evolution is just much older and well-tested than string theory.

Re:It depends upon what the definition of a theory (2, Insightful)

Black Parrot (19622) | more than 8 years ago | (#14675166)

> isnt anything that is purported to be true as a result of some a mathematical proof a theorem and something that is known to be true but has no proof a postulate(Law)?

Notice that "theory" and "theorem" are different words. Theorems arise from applying rules of inferences to sets of axioms (and previously proven theorems).

In general, the empirical sciences work by induction and hypothesis testing rather than by applying rules of inference to known truths, and thus don't produce theorems.

As others have pointed, there are several meanings of the word "theory", even in the world of science. I don't know the history of it, but I suspect "string theory" is called a theory because of its very mathematical nature, like "computational complexity theory". [wiktionary.org]

Also, I suspect we will continue to call it "string theory" even if it is eventually shown to be wrong.

I'm not crazy about that choice of names for it - we don't have any problems naming GR or QM without putting "theory" in the name - but language and terminology seem to have lives of their own.

Re:It depends upon what the definition of a theory (4, Insightful)

bunratty (545641) | more than 8 years ago | (#14674815)

You may not believe this, but the English language is often ambiguous. Some words have two, three, four, or more meanings. The word theory [google.com] is one of those. One definition of theory is a widely tested and accepted set of principles, as in Einstein's theory of relativity, which gives specific predictions about the universe that have been time and again proven correct to a high degree of accuracy. Another definition of theory is a hypothesis that has not yet been verified, as in string theory, which has not been scientifically verified at all. Yes, this ambiguity causes no end of confusion when one refers to the "theory of evolution". Many of us sit back and chuckle as people refer to it as "just a theory".

Re:It depends upon what the definition of a theory (1, Interesting)

Anonymous Coward | more than 8 years ago | (#14674854)

Theories are testable. The problem is that until now, the "String Theory" people insisted their theory was testable, we just lacked the technology to test it. Thus, other scientists told them to get their heads out of the clouds and work on something serious.

Now that this technology is on the horizon, the scientists are developing tests that will prove string theory to be "incomplete" (aka, wrong) by generating scenarios that do not match the predictions made by String Theory (in this case, that they can generate more dimensions than String Theory allows for). If the correct number of dimensions appear every time the micro blackhole is created, then we know that String Theory has the number of dimensions correct, to the best of our ability to measure dimensions (perhaps our understanding of these equations is incorrect, or our measurement equipment is missing something). This doesn't make it "right", it merely makes it "less likely to be wrong". So the scientists will think up some other way to challenge the theory.

Re:It depends upon what the definition of a theory (2, Insightful)

mcelrath (8027) | more than 8 years ago | (#14674861)

Unfortunately, there is no official body which confers the moniker "theory" to bodies of work which are deserving. Rather, people just call it that so that's how it's known. It is not a theory in the scientific sense. One should really call it String Hypothesis or String Postulate.

It is a theory in the mathematical sense similar to Group Theory, Set Theory, or Ring Theory. In mathematics these "theories" really refer to the specific set of axioms assumed. There exist some axioms (well, really, assumptions) that define the body of work that is "string theory". But one should not confuse string theory for mathematics. There are few rigorous proofs in the literature, a very large set of assumptions, and a large set of unproven conjectures.

In practice, unless a very bizarre set of miracles occur (such as the fundamental scale of gravity being much, much lower than we measure it to be -- such as is assumed in the article), there is no way we will ever conclusively prove string theory to be correct. It will always be possible to write down a different theory which gives the same physics, but is far simpler. String theory is not falsifiable and therefore is unlikely to stand the test of time. (or, maybe, it will live forever -- kind of like dragons and vampires)

-- Bob

Re:It depends upon what the definition of a theory (1)

GoofyBoy (44399) | more than 8 years ago | (#14674901)

>String theory is not falsifiable

Assume I have very little understanding of string theory. Could you please explain this in more detail; exactly what part and why string theory is not falsifiable.

Re:It depends upon what the definition of a theory (1)

davidoff404 (764733) | more than 8 years ago | (#14675052)

I would assume he is referring to the popular notion that string theory doesn't make any measurable predictions. Since a theory which doesn't make predictions is, by definition, not falsifiable, string theory would therefore qualify as a non-falsifiable theory.

Of course, saying that string theories don't predict anything is just plain wrong...

Re:It depends upon what the definition of a theory (1)

arminw (717974) | more than 8 years ago | (#14675552)

....Since a theory which doesn't make predictions is, by definition, not falsifiable, string theory would therefore qualify as a non-falsifiable theory.......

In that case, this also fits the theory of evolution. Evolution attempts to explain the past, but what predictions does it make of the future than could be checked out by experiment? I'm not taking about breeding or adaptation here, but the jumps from simple organisms to more complex. Even more so, why has nobody yet done by diligent effort what supposedly happened by accident--- the creation of life from non-life? How about putting one or two, or even a hundred non-life derived chemicals together and making a simple cell or even a virus? Evolution makes no predictions on how this might be done.

Re:It depends upon what the definition of a theory (2, Insightful)

hoggy (10971) | more than 8 years ago | (#14675927)

In that case, this also fits the theory of evolution. Evolution attempts to explain the past, but what predictions does it make of the future than could be checked out by experiment?

You are joking, right? The Theory of Evolution does not "attempt to explain the past" - it attempts to explain how one can get from point A to a later point B. We just happen to have mostly developed and verified the theory by looking at As and Bs that are in the past.

When one has access to an overwhelming amount of past evidence that can be compared against, one doesn't need to wait the 10s of millions of years necessary to see if it happens again.

That anyone doubts the truth of Evolution anymore I see as an astonishing failure of the school system.

Re:It depends upon what the definition of a theory (2, Insightful)

hcdejong (561314) | more than 8 years ago | (#14676322)

one doesn't need to wait the 10s of millions of years necessary to see if it happens again.

The drawback of only having historical data is that there are quite a few holes in that data (IOW the sampling rate is rather low).
Using this data we don't get to see evolution in action, we see only the end result of what we assume/theorize must be evolution.
So in this case, yes we would benefit from 'seeing if it happens again'.

Re:It depends upon what the definition of a theory (1)

Threni (635302) | more than 8 years ago | (#14676125)

> Evolution attempts to explain the past, but what predictions does it make of the future than
> could be checked out by experiment? I'm not taking about breeding or adaptation here, but the > jumps from simple organisms to more complex.

Organisms evolve to better fit their environment. As you've conceded, this can be seen via breeding experiments. So if by `more complex` you mean `better apapted to fit their environment` then that's what is shown by breeding experiments.

> Even more so, why has nobody yet done by diligent effort what supposedly happened by
> accident--- the creation of life from non-life? How about putting one or two, or even a
> hundred non-life derived chemicals together and making a simple cell or even a virus?
> Evolution makes no predictions on how this might be done.

If you're suggesting that because the theory of evolution hasn't explained everything means that it's yet to be proved, then you're wrong. Also, the gap between life and non-life is not as clear cut as you suggest.

You might want to read this:
http://www.talkorigins.org/faqs/abioprob/ [talkorigins.org]

Re:It depends upon what the definition of a theory (1)

arminw (717974) | more than 8 years ago | (#14676415)

.....If you're suggesting that because the theory of evolution hasn't explained everything means that it's yet to be proved, then you're wrong......

The orginal article was about testing string theory predictions EXPERIMENTALLY, thus determining if I set up condtions A, then result B will follow. If result B does happen, then the theory is on the right track and further tests can be done to refine the theory. If not then the theory gets thrown out or modified and new experiments done to test the refined version.

That's what happened with Einstein's theory of relativity. A TRUE theory of science is, that if I set up conditions A in an experiment, then result B should be observed. Many REPEATABLE, consistent experiments like this have been done with Einstein's theory, but what similar experiments have been done to show that the theory of evolution is an accurate predictor of the future? Nobbody has made evolution happen in the laboratory. Nobody has been able to take non-living chemicals and make even the simplest living thing out of them, thus PREDICTING the future through experiment. Nobody has ever taken a number of simple cells as building blocks and contructed a simple self sustaining multicellular organism -- kind of like biological lego blocks. Evolution is a conjecture, postulating immense eons of time, of how things may have come to be through the distant past, but has not in any way shape or form been experimentally tested in a lab, such as many other theories of science. Even the so called "missing links" from the past have never been found, because the are just that -- "missing" --ie. they never existed.

Real science requires EXPERIMENTS that can be done by anyone with the right tools and that will ALWAYS give results consistent with the theory behind the experiment. When scientists can devise a consistent, repeatable experiment that shows how life can come from non-life, then evolution rises to a falsifyable, experimentally verified theory. Until then it is a conjecture, believed by faith, of how things may have happened in the past, but not a predictor of the future.

Re:It depends upon what the definition of a theory (1)

mcelrath (8027) | more than 8 years ago | (#14675436)

  1. We will never build a collider with a center of mass at the (4-dimensional, normal) Planck scale.
  2. Given any measurement at low energies, it is possible to construct multiple string theories describing all existing observations. Any new measurement will slightly reduce the set of possible theories, but we will never hit upon a unique solution. Even if we did build a Planck scale collider it is still possible to get multiple string theories. (here I mean theory in the tested, scientific sense)
  3. Recent claims by stringers about explaining the cosmological constant by eternal inflation plus the anthropic principle are untestable, even in principle. (because we can't do experiments outside our own universe) Therefore, this aspect of string theory can never be more than a religious-like belief.

So at the end of the day, the whole thing is non-predictive (due to the multitude of indistinguishable models from low-energy experiments) and non-falsifiable (due to being able to wiggle out of any conceivable measurement).

Up until the recent anthropic arguments I was even willing to still call string theory science. But it is now careening over the edge of superstition. The anthropic arguments are unprovable in principle, and therefore, not science. (I could rant about this for a few more pages...)

-- Bob

Re:It depends upon what the definition of a theory (1)

GoofyBoy (44399) | more than 8 years ago | (#14676111)

I'll have to look up this stuff later on but thank you for giving me pointers on what to look for.

Re:It depends upon what the definition of a theory (4, Insightful)

shawb (16347) | more than 8 years ago | (#14674911)

One should really call it String Hypothesis or String Postulate.

In cases like this, untested ideas about the function of the universe, I personally like the term "model." You can use it to posit the inner workings of the universe and why things happen, but untill the technology is there and the experiments have been run it is not fully a scientific theory. But I believe it does fall within the bounds of model. And the nice thing about this is that with a model, you can make some assumptions that may or may not be true to simply explore how the world would work supposing this is true.

My favorite correlary is light. We have a model of light behaving as a wave, and that model has been proven to be wrong under certain cirumstances. We have a model of light behaving as a particle, and that model can also be proven wrong under certain circumstances. However, the fact that each model is not completely correct does not mean that they are useless. The basis of the model can be used to make further predictions about the way the world works, or even to produce technology through engineering.

Re:It depends upon what the definition of a theory (1)

mcelrath (8027) | more than 8 years ago | (#14675392)

Yes it's easier to explore the workings of the universe within the context of a model, but that does not in any way tell you that the model is correct. It's little more than a toy. I am absolutely certain that someone will eventually write down a model within the context of string theory that contains the particles we see. I'm also absolutely certain there will be thousands of others that will eventually be written down that are indistinguishable. This doesn't help us make any predictions in particle physics.

A photon is both a particle and a wave, at all times. This is a common misunderstanding of the physics, unfortunately propagated by popular literature. One can solve certain problems easier by assuming that it is one or the other (e.g. the wave nature of a gamma ray is pretty useless, and the particle nature of radio waves is too), but the same equations govern both. All particles are both particles and waves, and for practical purposes we drop the distinction and call them all "particles".

-- Bob

Re:It depends upon what the definition of a theory (1)

afaik_ianal (918433) | more than 8 years ago | (#14675085)

String theory is not falsifiable and therefore is unlikely to stand the test of time.

It most certainly is falsifiable - we just don't quite have the technology to test it yet, but by all measures, we appear to be pretty close (hence the article).

Assuming they produce a mini-blackhole with the LHC, if the observations do not match string theory's predictions, then it will have been falsified. They then need to either throw it out, or take it back to the drawing board.

Re:It depends upon what the definition of a theory (1)

mcelrath (8027) | more than 8 years ago | (#14675404)

No, if they do not produce a mini-black hole at the LHC, then gravity is not at the scales probed by the LHC. The extra dimensions are a little smaller, or we live confined to a brane.

That's what I mean by non-falsifiable. For any given conceivable measurement, there is a way to tweak the string theory to get around it. It can be discovered, but it can never be falsified. In this sense it is maximally non-predictive.

-- Bob

Re:It depends upon what the definition of a theory (2, Insightful)

GoofyBoy (44399) | more than 8 years ago | (#14674862)

>how was the "theory" part conferred?

There is no governing body that certifies theories. Saying something is a theroy does not specify how certain it is, how close it is to the "truth", how popular it is, how accepted it is within a group, how does it compare to other theories, how close it is being falsified. "Being worthy of academic discussion" is another idea.

(Some people would be scared because of this, saying that it makes science weak. But it doesn't, because science is about being open to ideas and exploring them, which means that everything is open, even to "crazy ideas" like string theory which should be evaluated and proven/disproven by its merits along, not on some title given by a set of people.)

I predict (3, Funny)

Centurix (249778) | more than 8 years ago | (#14674751)

That when they find out that String Theory is String Fact, they'll find out that the string was placed there to keep the nano-kittens occupied.

Re:I predict (1)

TubeSteak (669689) | more than 8 years ago | (#14675051)

Awww... that makes me think of Pixel from Heinlein's "The Cat Who Walks Through Walls".

Pixel is a kitten and walks through walls. Someone said "That's impossible! How does he do that?" and the reply was "Well, he's too young to know it's impossible ... so he just goes ahead and does it anyway!"

Even though Pixel is nicknamed "Schrodinger's Cat" I'm sure he plays with String Theory too.

Missed the asterisk (1)

blamanj (253811) | more than 8 years ago | (#14674756)

It says "under certain conditions." That is, if I read the article correctly, they have equations which say if the micro-black hole decays in a certain way, it will mean there are more than 11 dimensions.

Of course, if it doesn't decay as they predict, then their test fails and they've proven nothing about string theory. And that's assuming their math is correct.

Re:Missed the asterisk (1)

techno-vampire (666512) | more than 8 years ago | (#14674846)

Of course, if it doesn't decay as they predict, then their test fails and they've proven nothing about string theory.

Wrong. It will prove that there are not more than 11 dimensions. It may provide evidence that there are less, or that there are exactly 11 dimensions as well.

String? (2, Funny)

Jarn_Firebrand (845277) | more than 8 years ago | (#14674793)

How is string supposed to predict the amount of dimensions? Do they drop it in a black hole and see how far it goes, and use it from that?


Sincerely, Confused in the Fifteenth Dimension

Re:String? (1)

IorDMUX (870522) | more than 8 years ago | (#14675018)

The key is to see if a black hole even appears.

Current [as in "widely accepted"] physics states that such a black hole will not form in the collision planned, but, if string theory is correct and there are extra dimensions, gravity will be strong enough at the quantum level to cause a miniscule black hole to appear [extremely] briefly and then vanish suddenly in a fit of Hawking radiation.

By the way... think that extra dimensions are weird? How about a theory that says that volume is an illusion [wikipedia.org]?

Re:String? (0)

Anonymous Coward | more than 8 years ago | (#14676294)

That's the easy part. Given the number of strings visible in, say, GGW videos vs. the number of strings visible in my neighborhood (even on a sunny day), I must conclude that GGW videos were made in another dimension.

OT: String theory special on science channel (1)

Stevyn (691306) | more than 8 years ago | (#14674817)

This is off topic, but last night I was watching a special on string theory on the science channel - another discovery channel. And while it first seemed interesting, about halfway through it I realized it was almost completely devoid of actual information. Other than cool graphics and bouncing numbers, very little on the theory was actually presented.

I'm gonna read the article on wikipedia, maybe I'll get some more information.

Re:OT: String theory special on science channel (1)

mikael (484) | more than 8 years ago | (#14674932)

Is it my imagination, or does everything on the Discovery channels in the UK seem to be related to either World War II, hurricanes, tornados, crime, accidents? I haven't been able to find anything related to the latest science news. There used to be Discovery 2000, but maybe that was some time ago. There just doesn't seem to be any sort of weekly science update like a video version of New Scientist.

Further OT: Jay Leno joke. (1)

Black Parrot (19622) | more than 8 years ago | (#14675024)

> Is it my imagination, or does everything on the Discovery channels in the UK seem to be related to either World War II, hurricanes, tornados, crime, accidents?

A few weeks back Jay Leno observed, "This week in 1933, Adolph Hitler came to power in Germany... thus creating The History Channel."

Re:Further OT: Jay Leno joke. (2, Funny)

Beolach (518512) | more than 8 years ago | (#14675510)

I had a history professor who called the History Channel "All Hitler, all the time." I found it very funny when I happened to be watching it one night, when they were talking about the history of building roads... and of course talked about Hitler in conjunction w/ the German autobahnen.

The Knot Test (1)

slashbob22 (918040) | more than 8 years ago | (#14674827)

"A knot [slashdot.org] is a method for fastening or securing linear material such as string by tying or interweaving."

So obviously, if the knot test succeeds we can assume the string theory holds together.

WTF? (2, Funny)

Lord_Dweomer (648696) | more than 8 years ago | (#14674840)

"which would consist of creating and examining 'micro-black holes', which could be formed by smashing two high energy protons together."

Since when have we been able to create micro-black holes? Man.....screw lightsabers, i want a gun that shoots micro-black holes!

FYI: String Theory per Wikipedia (3, Informative)

Sundroid (777083) | more than 8 years ago | (#14674850)

From Wikipedia: "String theory is a model of fundamental physics whose building blocks are one-dimensional extended objects (strings) rather than the zero-dimensional points (particles) that are the basis of the Standard Model of particle physics..."

Here is the article:http://en.wikipedia.org/wiki/String_theory [wikipedia.org]

String Theory question (3, Interesting)

MSBob (307239) | more than 8 years ago | (#14674928)

Question for the theoretical physicists in the slashdot crowd:

If one day string theory is validated by an actual experiment what consequences will it have for the various interpretations of Quantum Mechanics? Is it going to give more credibility to any one of the interpretations of QM? Or is this a completely orthogonal issue?

Disclaimer: I know nothing about String Theory but methinks that a true Theory of Everything must provide us with an unambiguous answer for the nature of the collapse of a wavefunction, no?

Re:String Theory question (0)

Anonymous Coward | more than 8 years ago | (#14674989)

"methinks that a true Theory of Everything must provide us with an unambiguous answer for the nature of the collapse of a wavefunction, no?"

I dunno, we have an umabiguous answer for its nature already. It's the step of the calculation you perform to get the answer out. Maybe that's all there is to it, the universe doesn't have to be elegant.
I'm not suggesting we shouldn't investigate it, of course. Looking at similar apparent problems in the mathematics has brought us wonderful things like relativity. Just don't hold your breath...

Re:String Theory question (1)

MSBob (307239) | more than 8 years ago | (#14675017)

well, most physicists do regard wavefunction collapse as more than just a mathematical tool. There appears to be something that really transforms a wave into a stream of particles. we just don't quite understand when and why that happens.

Slightly Misleading Title... (4, Informative)

Sevaur (780102) | more than 8 years ago | (#14674943)

Peter Woit, a critic of string theory, points out some of the misleading bits in this article on his blog, "Not Even Wrong: http://www.math.columbia.edu/~woit/wordpress [columbia.edu] (scroll down for it). A brief discussion of why this isn't quite as exciting as it may sound.

JoAnne Hewett (one of the original authors) also comments in the blog, saying that the journalists tried to make the work a little more accessible by suppressing important details: As for the headline that is blazened on the SLAC home page - I saw it for the first time when someone drew my attention to it. I knew it was going to cause headaches...

So while this may be solid work, it doesn't seem quite so sexy as it has been made out to be...

As scientific theories go... (3, Insightful)

MikShapi (681808) | more than 8 years ago | (#14675230)

>> By determining how many dimensions exist, Hewett and Rizzo hope to either confirm or repudiate string theory

You cannot confirm a theory.
An experiment can either support it or disprove ("repudiate") it.

Scientists never learn (3, Funny)

tribentwrks (807384) | more than 8 years ago | (#14675397)

You'd think they'd leave this stuff alone after the "incident" over at the Black Mesa Facility. I think 4 dimensions is plenty for us right now.

Test? (1)

Belseth (835595) | more than 8 years ago | (#14675457)

Does it involve two tin cans and buttons? I believes I performed that test some thirty years ago. It acts as a primitive form of cell phone as I remember.

Obligatory Simpsons quote (0)

Anonymous Coward | more than 8 years ago | (#14675499)

Take that, you lousy dimension!

not "revolutionary" (1)

idlake (850372) | more than 8 years ago | (#14675782)

Even when string theory was new, it was hardly "revolutionary". It was more like SP17 for an already aging and proplematic physical theory.

A blast from the past... (1)

3waygeek (58990) | more than 8 years ago | (#14676359)

I knew both Hewett & Rizzo back in the early 80s when I was a physics undergrad at Iowa State -- JoAnne was a few years ahead of me, and Tom was a newly-minted professor, just out of post-doc.

I remember Tom telling us about supersymmetry (an ancestor of string theory) around 1983. God, I feel old...
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