A peek behind the curtain of the most infamous cosmic blunder of our time

I was once stupid too, and still am in many ways. One of the instances when I was more stupid than usual was when I wrote an article about the now-infamous BICEP2 ‘discovery’ of evidence of cosmic inflation in 2014. The ‘discovery’ eventually turned out to be a non-discovery because the scientists behind it had acted too soon with their announcement, overlooking a serious gap in their data.

As a science journalist, I’d failed because I hadn’t solicited independent comments for my piece, as a result letting The Hindu (where I worked at the time) publish an eminently wrong article. I will never forget that this happened, if only to remind myself of the importance of soliciting independent comments on all science articles, no matter how mundane the peg.

The BICEP2 instrument studies the cosmic microwave background (CMB) radiation. Some scientists were using BICEP2 to detect the imprint of gravitational waves on the magnetic component of the CMB radiation. Specifically, they were looking for some curling patterns in the magnetic mode associated with a rapid expansion of the universe thought to have happened between 10^-36 and 10^-33 seconds after the universe was born.

This expansion has been called the cosmic inflation and the period it happened, the inflationary epoch. Cosmic inflation was a hypothesis that sought to explain why parts of today’s universe seem to have similar physical features despite being separated by billions of lightyears. If cosmic inflation didhappen, the explanation would be that, once upon a time, the universe was very small and these distant parts were in fact more closely packed together then.

The first announcement, on March 17, 2014, was marked with a lot of fanfare. It was cosmology’s big day, and news publications around the world covered the announcement. Most of them included comments from scientists not involved in the data-taking, scientists who said something about the results was suspicious. That suspicion snowballed over time into a full-blown rebuttal that, within a few months, torpedoed the original study and forced the authors to apologise.

The problem turned out to be that gravitational waves couldcause the curling pattern on the magnetic mode of the CMB – and so could radiation emitted by cosmic dust, as seen by BICEP2. And the BICEP2 data was found to have recorded only the effects of cosmic dust.

In the last four years, I’ve realised how I had acted stupidly and learnt an important lesson the hard way. However, I was still curious why the BICEP2 team had acted stupidly. And though it seemed obvious, I had trouble accepting that the team had behaved the way it had simply because it was so excited, because it wanted to become famous.

On April 19 this year, Nautilus published an essay by Brian Keating, adapted from a book he has written about the BICEP2 fiasco. Keating was one of the leaders of the collaboration behind the announcement, working at Harvard University’s Centre for Astronomy (CfA). The essay provides a behind-the-scenes look at how scientists had missed the cosmic dust signal in their data analysis.

By the end of the essay, Keating appears to try to assuage readers that this was how science worked, that “you put out a result, and other scientists work to test the result”. However, the essay in toto highlights this is not how science works, and that this image of scientific endeavours is far too idealistic.

For example, a constant undercurrent throughout the enterprise seems to have been a rush to scoop. Keating et al had their eyes on a Nobel Prize, and wanted to be the first group to make the announcement that they’d seen the remains of the universe’s “birth pangs”.

He says this rush is why his team decided to present their BICEP2 results to the press even before the corresponding paper was peer-reviewed and published in a science journal. He writes:

… we feared that sending the paper to a journal would be unfair, giving a particular group – referees and their friends – a head start on proposal submission. My field is so competitive that the only people who weren’t on BICEP2 who could have reviewed the highly technical aspects of the paper were competitors. Our first priority was to make a scientific presentation to communicate our results to all our peers in the cosmology community.

Next, it seems the CfA team had been aware that dust in the Milky Way could play spoilsport to their apparent discovery, so they tried to get data from the team operating the Planck satellite. This satellite measures electromagnetic radiation across a wide swath of the sky, much larger than the BICEP2 survey area, and in a larger range of frequencies as well.

One of these frequencies was 353 GHz, at which Planck was able to study the effect of cosmic dust exclusively. The CfA team needed this data – but despite multiple requests, the Planck team refused to share the data. This is big news to me because I had no idea the CfA and the Planck teams treated each other as competitors! If only they’d worked together, the BICEP2 fiasco might never have happened.

… such a map [of cosmic dust] did exist, one with the exact high-frequency data we needed. There was only one catch: It belonged to our competitor, the Planck satellite. And in early 2014, the Planck team hadn’t yet released their B-mode polarization data. We were scared Planck might not only hold the key to proving our measurement right, but might have already glimpsed the inflationary B-mode signal before we did. … We desperately tried to work with the Planck team, while being careful not to tip them off as to what we’d found … [but they] wouldn’t cooperate. Either they didn’t have the data we wanted, or they did have it and they were going to scoop us. We had to go it alone.

Soon after, Keating and his team found a picture of a Powerpoint slide posted online that appeared to be from a talk given by one of the Planck team members. They decided to use the information presented in the slide, which suggested that BICEP2 had good and legitimate data, even though they weren’t sure if the slide was meant for quantitave analysis.

Thus, March 17 came and went, then June did too, when the CfA team’s paper was published in the journal Physical Review Letters. Then, around November, the Planck team had their paper published. As Keating writes,

With the Planck 353 GHz paper appearance came the beginning of the end of the BICEP2 team’s inflation elation. Although the Planck team was careful to release no data for the Southern Hole, the field where BICEP2 observed—perhaps out of fear we would digitize it—they made a blunt assessment of the potential amount of dust polarization contamination in the Southern Hole, saying it was of “the same magnitude as reported by BICEP2.” This meant dust was as likely a culprit for our B-modes as were inflationary gravitational waves.

The BICEP2 story well elucidates how science really works.

“Scientists are people too” is one way to put it. Another, and possibly better, way is to remember that institutionalised tendencies like torturing the data to yield more papers, conducting research to attract a Nobel Prize and scooping the competition aren’t one-offs, and that it’s foolish to think they wouldn’t percolate through the scientific community to create flawed ambitions.

These are all essential components of how humanity produces its knowledge. In other words, the scientific enterprise isn’t one that’s free of human foibles.

Featured image: The BICEP2 telescope (right) in Antarctica. Credit: Amble/Wikimedia Commons, CC BY-SA 3.0.