This week’s press release trumpeting a bogus “test of string theory” comes from the University of Illinois at Urbana-Champaign, which is headlined Scientists propose test of string theory based on neutral hydrogen absorption, and informs us that
Ancient light absorbed by neutral hydrogen atoms could be used to test certain predictions of string theory, say cosmologists at the University of Illinois. Making the measurements, however, would require a gigantic array of radio telescopes to be built on Earth, in space or on the moon.
String theory – a theory whose fundamental building blocks are tiny one-dimensional filaments called strings – is the leading contender for a “theory of everything.” Such a theory would unify all four fundamental forces of nature (the strong and weak nuclear forces, electromagnetism, and gravity). But finding ways to test string theory has been difficult.
Now, cosmologists at the U. of I. say absorption features in the 21-centimeter spectrum of neutral hydrogen atoms could be used for such a test.
One peculiar aspect of this press release is that it seems that the relevant paper is not yet publicly available. Supposedly it has been submitted to PRL and accepted, but it has not yet appeared in PRL, and I don’t see a preprint on the arXiv (the authors do have a PRL paper with an arXiv preprint from last year on a different topic, one that also came with a press release, but this one didn’t mention string theory).
As far as I can tell from the press release the idea behind this “test of string theory” is the same as lots of other similar ones that invoke cosmic strings. Among the huge variety of string theory backgrounds and the many possible ways to try and use such backgrounds to model the big bang, some will (just like some non-string theory GUT models) produce macroscopic “cosmic strings”. Astronomers have looked hard for evidence of such things and found none, but one can always imagine that, miraculously, such things exist, with characteristics exactly such that they wouldn’t have shown up so far, but would in some new, improved astronomical observations. In this case, I guess to come up with some new possible observation not already ruled out, the authors of the paper invoke a possible radio telescope with an area of a thousand km2.
There seem to be at least a couple reasons for the recent flood of bogus “we’ve found a test of string theory” press releases. One is that PRL evidently encourages authors to issue press releases whenever they have a paper appearing in PRL. Another reason is that string theorists are on the defensive, and some of them have decided that finding some way to claim that string theory really is testable, no matter how dubious, is the way to fight back. Earlier this month, one such claim hyped in New Scientist carried the headline “slammed for their failure to explain how our particular universe came to exist, string theorists are fighting back.” In an interview with string theorist Thibault Damour in today’s edition of the Swiss paper le Temps, he promotes three possible tests of string theory. One is the possibility (which he describes as “very speculative”) that one might observe extra dimensions at the LHC, another is cosmic strings, and finally there are his claims that string theory leads to violations of the equivalence principle. Lubos Motl strongly disagrees. Lubos also has a posting about this latest hype, where he comments:
Such possibilities highlight that creative people may often solve questions that look too difficult at the beginning. They also emphasize how incredibly idiotic are the aggressive crackpots’ proclamations that modern theoretical physics in general and string theory in particular is untestable.
Not clear who it is who believes that “modern theoretical physics” is untestable. While at Lubos’s blog, you might want to see what you can make of his posting on his new book The Bogdanov Equation: the secret of the universe?
Update: This story is appearing lots of places, including the UPI newswire, and at Wired, where the writer seems to realize that the bogosity level here may be problematic, including the unusual disclaimer:
Disclosure: I have no idea whether this makes sense.
Update: A correspondent points me to another recent “test of string theory”, one where for some reason the authors don’t seem to have issued a press release. The article is Toward a test of string theory using Rydberg atoms, and it begins by referencing my book and then claiming that
… measurable effects are predicted by String Theory on normal quantum scales, which the current criticisms have apparently overlooked.
What is discussed in the paper is actually not string theory, but just the idea of adding spatially non-commuting terms to the Heisenberg commutation relations. Certainly such terms should have experimentally observable effects. I suppose you can claim that such terms, of any size you want, come from a “string theory background”, but, as with all these “tests of string theory”, what is going on here just reflects the fact that you can pretty much get anything you want out of string theory, which is why it’s not testable…
This is off-topic, but…
“It’s a lot easier to disparage the work of others that to find something interesting yourself.”
Amused,
It’s time to stop inserting such remarks. You don’t effectively
advocate a position by saying someone you disagree with is somehow not qualified. In this case, not only does this remark undermine your position, but is incorrect. Peter W. is NOT unqualified. I say this as someone who does not always agree with him (though in the interest
of full disclosure, I will tell you that we are friends). For example, some papers Peter has written on topology and the lattice with many more citations than most on this topic (and were influential beyond the number of citations). You should also be aware that the number of papers per year written by a typical mathematician is much less than the number written by a typical physicist.
If we are going to argue our positions on the basis of our
qualifications, all of us are vulnerable. One can look at anyone’s record and put a negative spin on it.
amused,
Insulting me is a lot easier than acknowledging that what I wrote is accurate, isn’t it?
I actually agree with amused that I should be spending more of my time working on positive things, and less dealing with the problem of string theory hype in the media. In any case, the current rate of BS press releases every few days is beyond my capability of keeping track and commenting on. I do think someone should be pointing this out and no one else seems willing to do this. So I intend to keep doing so, but postings about this will be shorter.
One thing that really is a complete waste of my time is defending myself against the personal attacks of people like amused. So, sorry folks, I’ll just delete any more discussions pro (Thanks Peter O.!) or con of my competence here, and continue to let what I write speak for itself.
If you have something interesting to say about the topic of a posting, please do so. If you don’t know anything about it, but want to use it as an excuse to insult me or anyone else, please go away.
One of the first few string papers I read was Witten’s 1985 paper on cosmic strings. At the time I was in grad school and was naive enough to buy into it as if it was a “holy gospel”. I became more skeptical of the idea as time went on.
No I wasn’t questioning Woit’s qualifications etc. The point had nothing to do with that. It’s really simple: if someone wants to disparage work addressing some issue (in this case finding a theoretical underpinning for inflation) then they should provide a more promising approach to addressing the issue. I don’t find the string-inspired stuff at all appealing, so I don’t work on it, but at the same time I don’t disparage it since I don’t have any better proposal for the issues they are trying to address. Isn’t that a reasonable attitude that everyone should have? It has nothing at all to do with assessing peoples qualifications, publication lists etc.
So what was I trying to do here? First, ask questions to try to find out the actual situation about this paper, what was hype and what wasn’t. Second, react against the negativity directed to this and the other PRL papers in the “hype” posts.
“…If you don’t know anything about it, but want to use it as an excuse to insult me or anyone else, please go away.”
When you turn up on the blogs of Jacques Distler and Clifford Johnson to harangue them about their discussion of some string theory topic, their reaction is probably “please go away” as well. They are too polite to actually write it though. You don’t “go away” though, because you think you have some valid points to make and are determined to make them. What a surprise that you should encounter someone with the same attitude on your own blog. It’s funny to see how you deal with it.
“Insulting me is a lot easier than acknowledging that what I wrote is accurate, isn’t it?”
I asked a couple of questions; you answered one of them (sort of) and I acknowledged it with “Ok,…” at the beginning of my comment. You didn’t answer the other one (about whether cosmic strings are a generic prediction of brane inflation) so I went and found the answer myself. Btw, both questions were relevant to the topic at hand, wouldn’t you agree?
JC,
Cosmic strings certainly have a very long history by now. The early hopes for how to use them were conclusively killed off by the WMAP results, but people can always come up with new ones that can’t be shot down anytime soon by experimental results. For one of many disconfirmed predictions in this area, see this 1986 Time magazine article
http://www.time.com/time/magazine/article/0,9171,962896-1,00.html
where Ostriker is quoted as follows:
“We still don’t know that there are such things as cosmic strings,” he says, “or that they are necessarily superconductors or will in fact carry large currents. But all these things are quite possible. Within a few years, superconducting strings will have either transformed our view of the large-scale universe — or be entirely forgotten.”
Peter,
It was the repeated disconfirmations over the years which eventually led to my skepticism of cosmic strings. Even back then, many of my former astro colleagues thought the idea was sort of a joke.
amused,
Yes I did accurately answer your question about brane inflation, and not with vague hype about “generic predictions”.
Sadly, you have turned into a prototypical internet troll, devoting your time to posting hostile comments about things you know virtually nothing about. Before criticizing me for what I write about the hype problem in string cosmology, you might want to first go and learn the first thing about the subject.
Well, people can make up their own minds about whether the questions I asked and the rest of the comments were reasonable or not, and the same for Woits answers. Not much point in continuing with this.
‘The point … It’s really simple: if someone wants to disparage work addressing some issue (in this case finding a theoretical underpinning for inflation) then they should provide a more promising approach to addressing the issue. I don’t find the string-inspired stuff at all appealing, so I don’t work on it, but at the same time I don’t disparage it since I don’t have any better proposal for the issues they are trying to address. Isn’t that a reasonable attitude that everyone should have?.’
– amused
Amused, it’s unreasonable because if you ban attacks on popular ideas that are failures – unless the person who is attacking has a better approach to the problem – then the need for a better approach to be developed may never arise. It’s then Catch-22 because, only when a failed idea has first been found wanting, is there a need to develop a better approach.
If you insist that a better approach be developed before criticising failures in the current ideas, 1) nobody will listen because they’ll think you’re just trying to hype a new theory, and 2) you will eliminate the usual two-step route to advance, whereby a failed idea is first attacked, then replaced by new developments that are inspired by the faults in the existing ideas.
Historically, the two-step route to progress (discredit a bad idea, then afterwards develop a better approach) is more common that a one-step process of replacing an idea in one go without first making the case widely understood for why the idea needs to be replaced.
Your suggestion that criticism must always be constructive, while fine in an ideal world, will eliminate a lot of progress in this (real) world by preventing the two-stage progress model from working. People aren’t motivated to fix things that aren’t first known to be broken (‘if it isn’t broken, don’t fix it’). If an error is being made, the sooner it is publicised, the sooner it can be fixed. Any censorship of criticisms just slows down progress.
anon,
I should point out that what I’m doing here is criticizing misleading press releases about scientific results, not the scientific results themselves. Universities should not be in the business of issuing press releases about the work of their scientists designed to mislead the public about its significance, and when they do, someone should call them on it. I’d be very happy if someone else would be the one to do this.
It used to be that these press releases most of the time got pretty wide distribution, through articles in places like New Scientist, and on web-sites like Slashdot. Among the recent flood of them, most seem to not be getting much attention beyond the sites that carry all such press releases. Perhaps this is an indication that journalists covering physics have caught on to what has been going on. I suppose this is progress, but it isn’t a good thing that journalists and the public now are likely to be skeptical of the credibility of press releases about physics research put out by major universities.
anon,
Sure, criticising an approach, discussing its shortcomings etc is good and healthy. But that’s not what I see happening here. The impression from this post is that the paper under discussion is of no interest and worth but is just a vehicle to propagate more string hype. From reading the press release I got a quite different impression. So I asked a couple of questions to try to find out what the real situation is. The paper is apparently discussing an observable (in principle) imprint that cosmic string networks in the early universe would leave, and how it would give information on the brane inflation that gave rise to those networks if that’s what they came from. The level of PW’s criticism in this post seems to be that this is junk because you can get anything you want out of string theory so there’s no reason to care about what some or other string scenario might predict. But from what (little) I read about this in the string literature it sounds like the situation is quite a lot better than that. Apparently brane inflation is one of just a few scenarios that string cosmologists have been able to come up with, and within that scenario they say that cosmic string networks are a generic prediction. If that is true then the current paper seems not at all worthless and uninteresting.
In light of those observations, the right way to go about criticising this work would be to argue, at the technical level, that one or more of the reasons for being interested in it is flawed. E.g., if someone could show that there are lots and lots of different inflation scenarios (compatible with observational data) that can arise from string theory, and most of these do not predict cosmic strings. Or, alternatively, show that the arguments for why cosmic strings are a generic prediction of brane inflation are flawed. If someone can show either of these things they should write it up and publish it as a research article — that’s the way criticisms of scientific approaches are supposed to go.
The way scientific criticisms are not supposed to go is simply pouring buckets of negativity over the research efforts of serious scientists who are following their best judgement in a difficult situation — unless you have a better proposal for the issues they are trying to address.
‘The paper is apparently discussing an observable (in principle) imprint that cosmic string networks in the early universe would leave,…’ – amused
Amused, you’re missing the point: please see Woit’s point in reply to my comment above also applies to your comment:
‘…what I’m doing here is criticizing misleading press releases about scientific results, not the scientific results themselves. …’
It’s the press release about making a ‘prediction’ that is being criticised, not the paper. Without knowing definite initial conditions for a cosmic string, are you in a position to make a falsifiable prediction about how big it will become after the assumed inflation occurs within a minute fraction of a second after the universe? Are you even sure that your model for inflation is accurate? It hasn’t won any Nobel Prizes yet.
‘… the right way to go about criticising this work would be to argue, at the technical level, that one or more of the reasons for being interested in it is flawed. E.g., if someone could show that there are lots and lots of different inflation scenarios (compatible with observational data) that can arise from string theory, and most of these do not predict cosmic strings. Or, alternatively, show that the arguments for why cosmic strings are a generic prediction of brane inflation are flawed.’ – amused
Basic research work (to establish validity of claims) is something that the people making such claims need to do themselves, before actually issuing press releases hyping the claim. This isn’t the same situation as when issuing a preprint about a speculative idea.
It’s for the people making claims to investigate the main problems, not for the critics to do that after press releases have been issued. The problem is not that people are doing this research, but that there are very serious problems that are being glossed over in popular hype. It’s a bit like popular claims that supersymmetry ‘makes predictions’ because it requires a so far unobserved partner for ever observed particle. If the theory is wrong, you would never be able to find out: you would keep searching at every higher energies, for ever edging towards the Planck scale. There is no evidence why the theory is correct, and there is no possible way of ever showing it is wrong.
If the search for cosmic strings is actually a checkable test of string theory (unlike supersymmetry, gravitons, and brane worlds), then that would be a massive step forward.
amused,
You just keep on ignoring what this posting is about: a misleading press release. I did not claim the paper was worthless, I do claim that the press release about it is intentionally designed to mislead people about the results of scientific research.
anon,
Supersymmetry as a solution to the electroweak hierarchy problem is perfectly testable – it’s either around the weak scale or it doesn’t stabilise the Higss mass. There are good reasons for susy to exist at the weak scale – this is an answerable question, the LHC has the reach to answer this question and will answer this question.
piscator
Supersymmetry as a solution to the electroweak hierarchy problem is perfectly testable – it’s either around the weak scale or it doesn’t stabilise the Higss mass.
Okay, which I think is a good point. But the problem is, even if “susy as a solution to the electroweak hierarchy problem” is falsifiable, that still leaves the question of what about “susy as a method of getting matter into string theory”. It seems likely that work on susy would continue even if the hierarchy problem justification were removed.