I noticed today that BBC News has a story headlined ‘Multiverse’ theory suggested by microwave background that assures us that:
The idea that other universes – as well as our own – lie within “bubbles” of space and time has received a boost.
After taking a look at the PRL and PRD papers that are behind this, it’s clear that a more accurate title for the story would have been “‘Multiverse’ theory suggested by microwave background – NOT”. As usual, the source of the problem here is a misleading university press release, one from University College London entitled First observational test of the ‘multiverse’. Somehow the press release neglected to mention something one might think was an important detail, the fact that this “First observational test” had a null result.
It’s well-known that one can find Stephen Hawking’s initials, and just about any other pattern one can think of somewhere in the CMB data. The authors of the PRL and PRD papers first put out preprints last December (see here and here). In these preprints they essentially claimed to have found four specific features in the CMB where the hypothesis that they were due to bubble collisions was statistically preferred. A guest post by Matthew Johnson at Cosmic Variance explained more about the preprints. I didn’t understand their statistical measure, so asked about it in the comment section, where Matthew explained that, by more conventional measure, the statistical significance was “near 3 sigma“.
It turns out that the PRL and PRD papers differ significantly from the preprint versions. In the acknowledgements section of the PRD paper we read that:
A preprint version of this paper presented only evidence ratios confined to patches. We thank an anonymous referee who encouraged us to develop this algorithm into a full-sky formalism.
and the result of the new analysis asked for by the referee is summarized in the conclusion of the paper:
The posterior evaluated using the WMAP 7-year data is maximized at Ns = 0 [Ns is the average number of observable bubble collisions over the full sky], and constrains Ns < 1.6 at 68% confidence. We therefore conclude that this data set does not favor the bubble collision hypothesis for any value of Ns. In light of this null detection, comparing with the simulated bubble collisions... [various bounds ensue]
So, the bottom line is that they see nothing, but a press release has been issued about how wonderful it is that they have looked for evidence of a Multiverse, without mentioning that they found nothing. As one would expect, this kind of behavior leads to BBC stories about how the Multiverse has “received a boost”, exactly the opposite of what the scientific evidence shows.
Update: The FQXI web-site has an article about this. In it, the authors seem far more interested in promoting their PRL paper as “first test of the multiverse” than in acknowledging that a referee made them do a better test of the idea and they got a null result. There’s no mention of the null result in the article.
Update: News stories based on this keep on coming. The latest: Proof of a multiverse discovered?
After following your blog for the last several months, I think it will soon be time for a new book, Peter (I read the first one). 2012, when the Higgs and other “predictions” have been ruled out would be a good timing for an update on the state of theoretical physics. I’d buy that book. You working on it?
University press releases are always suspect If my institution is any example, such offices are paid to make the big splash, putting them one step below the tabloids.
That would be above the tabloids. I think.
I also wrote about the Feeney et al paper here.
No plans for a new book. So far, the situation described in the old one hasn’t much changed (except that string theory has become a lot less popular). I hope new physics worth writing a book about comes out of the LHC, but if so there likely will be many people doing a better job than me of writing such a book.
“…exactly the opposite of what the scientific evidence shows.”
Scientific evidence?? Peter until now your mantra was that the multiverse hypothesis is pseudo science because it can’t be tested; now you are saying that it can? Then surely is not pseudo science…
I agree that over-hyped press releases are a big problem, compounded by the fact that certain web sites aggregate press releases making them look like they are journalistic reports, as you have pointed out in the past. Do you agree, though, that some universities have more reliable press offices than others? And ultimately, when a supposedly reliable publication covers something, it’s that publication’s responsibility to see the science (if there is any) through the hype.
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@Giotis: The fact that they tested the idea of the existence of Multiverse is not a proof that this idea is a valid scientific theory. It would have been a valid scientific theory and I’m sure that Peter would have been happy to recognized that he was wrong, if after testing their theory and finding nothing, the scientist would have conceded that their theory had been refuted.
The issue with the Multiverse ideas is that they can’t be refuted. We cannot create a test that can disprove such theories. There’s always going to be way of saving this theory.
a blog technical question about the pingback
According to wikipedia, a pingback is added to your blog because this other blog on Intelligent Design has quoted your post. But does it require your approval ? (i.e. do you think that ID is an interesting answer to multiverse ?).
Someone should start a blog or wiki or weekly column all about university press releases: the good, the bad and the ugly. It might eventually exert some discipline on the people who write those releases, if word got back to them.
Davide and John,
I suppose the quality of university press offices varies, but the amount of hype they put out depends largely on what researchers are willing to feed them. A lot of these over-hyped press releases are the fault of PRL, which evidently has a policy of encouraging press releases when they publish papers. I find it hard to believe that many university press offices are issuing press releases over the objections of the researchers involved, or without letting them see the text of the release and vet it before it goes out. Few faculty that I know would tolerate their institution issuing without their approval a press release that they felt misrepresented their research.
If you look at the collected “This Week’s Hype” postings about university press releases I think there’s a pattern. They’re mostly about how someone at the university has made progress towards solving the problem of some well-known speculative theory being untestable. There’s every reason to believe that the researchers themselves think they have done this, and are on-board with the idea of a press release promoting their work. These press releases are often carefully worded with crucial caveats placed so as to be technically accurate, but highly misleading in that they don’t mention problems with the claims being made. When various news sources pick them up, it’s not surprising they often take them at face value, are successfully misled, and miss the significance of the caveats. Good news organizations aren’t fooled, do their own checking, and then decide to ignore the misleading press release, weaker ones are fooled.
You can blame the news organizations for getting fooled, or the press offices for spreading hype about topics they don’t really understand, but I think the most significant blame should go to the researchers themselves, who are either misrepresenting their own research or standing by and letting their employers do so.
pingbacks appear here automatically, without needing to be approved by me. If they’re spam, or from someone trying to introduce links to off-topic material here, I delete them when I get a chance. If they are legitimate postings of some kind that happen to refer to something here, I leave them, no matter what I think of the posting.
I happen to think that ID is worthless pseudo-science, and also that arguing with people over anything related to religion is a waste of my time and energy. One of the worst aspects of multiverse pseudo-science is that it delegitimizes real science, the best tool available for fighting irrationality. I’m glad that some people are willing to spend time making the argument against ID, mystified that some of them think it’s a good idea to sign on to multiverse pseudo-science as part of this argument. This seems to me ultimately self-destructive behavior. You can go ahead and say that the string theory anthropic multiverse deals with the argument from design for the existence of a deity, but you’re then stuck without a legitimate answer when IDers point out to you that their “science” is as good or better than yours.
Kyrilluk does a good job of explaining the point: there may very well be a multiverse, but current heavily advertised multiverse theories are often inherently unfalsifiable. If you have a theory compatible with almost everything, you can’t ever show it is wrong.
The authors here did a careful job of measuring something and achieved a real scientific result: they looked for evidence in the CMB of effects of certain kinds of bubble collisions and showed that no statistically significant such effects are visible in the WMAP data. Then, for unclear reasons, they allowed a press release to be issued implying that they had figured out how to “test” multiverse theories, but not mentioning that the “test” had failed. Perhaps mentioning that the “test” had led to a null result would have made it necessary to explain that this wasn’t the sort of “test” of multiverse theory that one might think it was, since failing the “test” wasn’t a problem for the theory.
To be clear: I don’t think studying models of the early universe involving bubble collisions is pseudo-science. You can make predictive, scientific such models, although I don’t personally think you’re ever going to find evidence for them. You’re going to get null results like in this work. What is pseudo-science is the use of the multiverse as an excuse for the failure of string theory unification. It is the heavily overhyped and oversold string theory landscape multiverse framework that is inherently unpredictive, untestable and unscientific. If you want to choose specific cosmological models with a multiverse and examine their observational implications, that’s not inherently unpredictive, untestable or unscientific. So far though, there’s no evidence for such models, so such work is highly speculative and likely to lead to nothing but null results, a good reason not to issue press releases about it.
Peter: thanks for the explanation.
A propos of delegitimizing real science: here’s a comment that Kenneth Miller, a biologist from Brown U. who makes the case in his book that science and religion are compatible:
“Believers … are right to remind skeptics and agnostics that one of their favored explanations for the nature of our existence involves an element of the imagination as wild as any tale in a sacred book: namely, the existence of countless parallel simultaneous universes with which we can never communicate and whose existence we cannot even test. Such belief also requires an extraordinary level of “faith” and the nonreligious would do well to admit as much.”
Hard to argue with the logic. The premise though is that theories “…whose existence we cannot even test.” is science…
When these papers refer to a collision between universes, in what space are the universes thought to be moving and colliding? And with what laws of motion?
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Here comments from “Physics”:
A bit off topic, for sure, but I am surely not the only one who bemoans the effect the multiverse ideas have on science fiction. True, they were writing multiverse stories long before the current popular mania, but now it is out of control. If I have to read yet another friggin’ intellectually lazy multiverse story, I might just go mad.
so much about the obsolescence and inadequacy of the refereeing process…
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Here is another popular article on this same issue:
“Weird! Our Universe May Be a ‘Multiverse,’ Scientists Say”
The way these people misrepresent their own work is outrageous.
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