Science by Press Release: Overhyped “gravity waves” were just dust

In March this year there was a great deal of publicity about the detection of gravity waves after the Big Bang. There were Press Releases and promotional videos and blanket coverage in the media. There was talk about Nobel prizes. Not unlike the massive publicity mounted by CERN about the discovery of (or more accurately the potential discovery of a possible indication of a particle not inconsistent with) the Higgs boson particle. After that non-discovery also there was talk about the CERN team being awarded a Nobel Prize! Even a member of the Nobel Committee was taken in by the publicity and fought for CERN the organisation, to be awarded  the physics prize. Most of the campaign in favour of CERN was initiated and orchestrated by the PR department at CERN and the CERN fan-club.

Now it turns out that the gravity waves may well have been cosmic dust.

BBCOne of the biggest scientific claims of the year has received another set-back.

In March, the US BICEP team said it had found a pattern on the sky left by the rapid expansion of space just fractions of a second after the Big Bang. The astonishing assertion was countered quickly by others who thought the group may have underestimated the confounding effects of dust in our own galaxy.

That explanation has now been boosted by a new analysis from the European Space Agency’s (Esa) Planck satelliteIn a paper published on the arXiv pre-print server, Planck’s researchers find that the part of the sky being observed by the BICEP team contained significantly more dust than it had assumed.

BIG Science of this kind needs BIG FUNDS. BIG FUNDS need BIG CLAIMS. A BIG CLAIM followed by a retraction is seen to be better – from a publicity perspective – than an uninteresting claim or no claim at all. The people who control the BIG FUND purse strings are generally governments in the form of bureaucrats and administrators and politicians. They don’t usually read the scientific papers themselves. But they do read the Press Releases and take note of the number of column-inches of newspaper articles that are generated. Promotional videos with many hits on You-Tube are also taken note of.

This is science by Press Release. Scientific quality is now judged by the amount of publicity generated.

I am not competent to judge the technical content of these “discoveries” and therefore have to rely on others who are. And so I take note of what Sean Carroll, a CalTech physicist writes on his blog:

Ever since we all heard the exciting news that the BICEP2 experiment had detected “B-mode” polarization in the cosmic microwave background — just the kind we would expect to be produced by cosmic inflation at a high energy scale — the scientific community has been waiting on pins and needles for some kind of independent confirmation, so that we could stop adding “if it holds up” every time we waxed enthusiastic about the result. And we all knew that there was just such an independent check looming, from the Planck satellite. The need for some kind of check became especially pressing when some cosmologists made a good case that the BICEP2 signal may very well have been dust in our galaxy, rather than gravitational waves from inflation (Mortonson and Seljak; Flauger, Hill, and Spergel).

Now some initial results from Planck are in … and it doesn’t look good for gravitational waves.

Planck intermediate results. XXX. The angular power spectrum of polarized dust emission at intermediate and high Galactic latitudes
Planck Collaboration: R. Adam, et al.

planck-bmode-spectrum

The light-blue rectangles are what Planck actually sees and attributes to dust. The black line is the theoretical prediction for what you would see from gravitational waves with the amplitude claimed by BICEP2. As you see, they match very well. That is: the BICEP2 signal is apparently well-explained by dust.

….. Planck has observed the whole sky, including the BICEP2 region, although not in precisely the same wavelengths. With a bit of extrapolation, however, they can use their data to estimate how big a signal should be generated by dust in our galaxy. The result fits very well with what BICEP2 actually measured. It’s not completely definitive — the Planck paper stresses over and over the need to do more analysis, especially in collaboration with the BICEP2 team — but the simplest interpretation is that BICEP2’s B-modes were caused by local contamination, not by early-universe inflation. ….. 

“Science by consensus” and “science by press release” and even “science by press release about the consensus” have infected much of what passes for science today.

Tags: , , , ,


%d bloggers like this: