Dusting off Last Spring’s Excitement

There has been quite a bit of discussion of the realisation that the exciting announcement made by the BICEP2 experiment back in March (see my post here) was based on erroneous analysis. (In brief, various people began to realise that most, if not all, of what they observed could be explained in terms of something more mundane than quantum spacetime fluctuations in the ultra-early universe – the subtle effects of galactic dust. A recent announcement by another experiment, the Planck team, have quantified that a lot.)

While there has been a bit of press coverage of the more sober realisations (see a nice June post on NPR’s blog here), it is (as with previous such cases) nowhere near as high profile as the initial media blitz of March, for better or worse. I think that “worse” might be the case here, since it is important to communicate to the public (in a healthy way) that science is an ongoing process of discovery, verification, and checking and re-checking by various independent teams and individuals. It is a collective effort, with many voices and the decentralised ever-sceptical scientific process itself, however long it takes, ultimately building and broadening the knowledge base. This self-checking by the community, this reliance on independent confirmation of results, is what makes science different from religion. People need to see and understand that, or they will never fully understand what science is really about. So it is a pity that the press coverage is so imbalanced, once again.

Anyway, I noticed an interesting summary by Resonaances about what went (in writer Jester’s opinion) right and wrong with this whole chapter, including the doing of the science itself, and how it was communicated. Have a look and decide if you agree or not.

-cvj

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7 Responses to Dusting off Last Spring’s Excitement

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  2. Stam Nicolis says:

    What I found interesting in this whole story is that BICEP2 had stated quite explicitly, in the preprint and in the published paper, the limits on the signal, i.e. that they could distinguish it from dust at 2.3 sigma (in the preprint) and 1.7sigma in the paper-both below discovery threshold, in fact below what’s accepted as the first threshold of 3sigma. This information was, apparently, completely ignored in subsequent discussions. The whole discussion should have stopped there. In fact, as was stressed both at the Caltech workshop and at Strings 2014, for the moment, there doesn’t exist a reliable model for the electromagnetic response of interstellar dust, that would allow it to be subtracted from a putative measurement to discovery precision-and Planck’s recent preprint is quite nuanced in that regard.

  3. Clifford says:

    Hi,

    Thanks for highlighting that. I think that initially everyone was rather bowled over by the boldness of the announcement and the manner and loudness with which it was done…. perhaps this served to sweep many people (even those with discerning eyes) along on a wave of excitement a bit further than under normal circumstances. If you look at Jester’s blog (linked) it is suggested that rather less attention (and hence fewer independent eyes in the team) than one would expect was given to this central player in the story…

    Well, mistakes happen. That’s why it is a wonderful thing that the process ensures self-correction, in the medium to long run, if not immediately.

    Cheers,

    -cvj

  4. Stam Nicolis says:

    I don’t agree that there was any “mistake” made-
    because the 2.3 sigma figure was in the preprint. From that alone one can say that there isn’t any reliable signal to debate about. But nobody stressed clearly enough that what this result means is just that they control the systematics of the detector and that’s aleady something to build on, when and if the dust background can be reliably subtracted. The point is that, until this background can be reliably described, it won’t be possible to estimate an inflationary electromagnetic signal to discovery precision and, eventually, other ways must be thought of to detect such a signal at all.

  5. Clifford says:

    Well, I would say that making such an announcement hoo-hah when there isn’t, as you put it, “any reliable signal to debate about” can be classified as a mistake.

    Cheers,

    -cvj

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