In anticipation of the book’s release, Professor Keating (BK) answered a few questions about his book, the BICEP2 results, and the Nobel Prize for
Astronomy magazine (AM):
AM: Cosmology in particular is a field that fascinates the public, but also isn’t a subject that most people encounter other than in sensationalized headlines. Do you think that the BICEP2 results and the window they opened onto the current scientific process have changed the public’s opinion on cosmology, or affected their confidence in the field?
BK: Cosmology has several things that both fascinate and irritate. Both revolve around the essential controversial nature of cosmology. First of all, we only have one cosmos (unless we live in a multiverse, then all bets are off!). So we cannot actually do experiments or study statistical samples. We can only rely on the data that comes to our telescopes after traversing the entire universe. On the way, things can get pretty messy. Secondly, cosmology of all the sciences, is closest in themes to religion, a subject which obviously arouses great passions in both scientists and laypeople alike. (Some of those themes are explored here: https://youtu.be/9Z5u0jDj7dg)
Regarding the irritating nature of cosmology: after our results were disconfirmed, Dartmouth astronomer Marcelo Gleiser said the BICEP2 experience “harms science because it’s an attack on its integrity . . . It gives ammunition for people to say, hey look those scientists don’t know what they’re talking about in cosmology and they don’t know what they’re talking about in general.” But I disagree because, in the end, the public did get a science lesson. Science is messy because nature is messy. Scientists are not infallible robots; we are human. We didn’t blunder: we didn’t leave the lens cap on or use dirty test tubes. Unlike cold fusion or faster-than-light neutrinos, BICEP2’s results were reproducible. In fact, we have more confidence than ever in BICEP2’s actual B-mode detection significance— which is an amazing accomplishment when you consider these signals are billions of times colder than even the frigid polar landscape where BICEP2 lived for three years.
BICEP2 showed the public how science works: you put out a result, and other scientists work to test the result. You put all your cards on the table, and leave it all out there for your critics. If and when they attack, you defend until you can defend no longer and the attacks subside. Only then, when both critic and supporter collapse, exhausted, can science be said to be settled.
So I’m not worried. Cosmology will survive BICEP2, and the many more messy episodes to come!
Courtesy Brian Keating
AM: Can you give a brief explanation of the type of cosmic dust responsible for the signal that BICEP2 picked up, and how it managed to masquerade as the signal you wanted?
BK: The signal that we saw seemed to be the imprimatur of inflation. But, eventually it was understood to be dust in our galaxy, which scatters and and polarizes the CMB light that we really want to see. It’s sort of like a car’s dirty windscreen: not only does it diminish the light of the road ahead, it distorts it as well. In our case, it can mimic the very B-mode signals we’re looking for. I didn’t realize at the time, but dust has always been a cosmic companion leading astronomers astray since the very first telescope ever used to look up the cosmos by Galileo.