“Then nearly 14 billion years ago expansion started.”
Woo-hoo! They’re dancing in the streets over how the Antarctic telescope BICEP2 has just provided the first actual data supporting the inflationary theory, the idea that the universe expanded spectacularly immediately after the infinitesimal point that was the Big Bang. Bad Astronomer Phil Plait says the news is “very esoteric—probably the most layered and complex announcement I’ve ever written about.” So be prepared, it’s Cosmology 2014.
The slightly bipolar general response among the knowledgeable is encapsulated by, among others, physicist Max Tegmark, writing at a SciAm Guest Blog, “if the BICEP2 discovery holds up, it will go down as one of the greatest discoveries in the history of science.”
We’ll get to the cautions in a moment, but note that Tegmark’s brief pro forma bow to scientific skepticism is swamped by his wholehearted embrace of the findings. And he is by no means an isolated case. Nearly all the blogging acknowledged perfunctorily that the data need confirming, but there seemed to be few true doubters.
Hints last week, the story this week
After an enormous amount of preliminary speculation over the weekend, finally a press conference last Monday. Matthew Francis explains on the wing at Ars Technica, “we’ve detected the first direct evidence of the inflationary phase of the Big Bang, in which the Universe expanded rapidly in size.”
“Rapidly” hardly begins to cover it. “Inflation is a bit of a mind-bender, I’ll admit. It started just about 10-35 or so seconds after the bang. To give you a better idea of how short a time interval that is, we’re talking 0.00000000000000000000000000000000001 seconds! And it only lasted until about 10-32 or so seconds later,” Plait says. (At 13.7 Cosmos & Culture, Adam Frank issues a correction. He got the number of zeroes wrong. It’s 34, not 35. I cut-and-pasted the number Plait used, so please direct your complaints to him or to Slate’s copy-editing department.)
As explained at Symmetry, the data depict the first images of gravitational waves, ripples in space-time. The violence of post-Big Bang inflation was such that it literally made waves. The observations of the cosmic microwave background—a faint glow left over from the Big Bang, were made by the #BICEP2 telescope. (BICEP is the muscular acronym for the Background Imaging of Cosmic Extragalactic Polarization experiment; the telescope is situated near the South Pole because the seeing is so good there.) The post contains links to the papers and technical details and notes that a paper has been submitted to Nature.
How to explain the near-inexplicable
Knight Science Journalism Tracker Faye Flam has followed this news since last week, describing how the media, mostly the print media, have been explaining this very big story that is nearly impossible to explain. On Monday she told of the hubbub following last week’s “maddening” press release from the Harvard-Smithsonian Center for Astrophysics, which promised Big News on Monday. Later that day she critiqued post-press conference pieces from several publications, including the New York Times, Nature, Scientific American, the AP, and other sources.
In her Wednesday post, headed “How to write a lede about a phenomenon most readers have never heard of, the discovery of which backs an important theory most people know nothing about” she declares the winner to be Joel Achenbach at the Washington Post. She deconstructs what he did and why it was exactly the right thing to do.
For your education, here’s what Achenbach did: “In the beginning, the universe got very big very fast, transforming itself in a fraction of an instant from something almost infinitesimally small to something imponderably vast, a cosmos so huge that no one will ever be able to see it all.
“This is the premise of an idea called cosmic inflation — a powerful twist on the big-bang theory — and Monday it received a major boost from an experiment at the South Pole called BICEP2. A team of astronomers led by John Kovac of the Harvard-Smithsonian Center for Astrophysics announced that it had detected ripples from gravitational waves created in a violent inflationary event at the dawn of time.”
Sean Carroll (the physics one, obviously) has posted on this news a number of times, but this particular link will bring you to some meditations on the discovery plus a clip of his explanatory interview Tuesday on the NewsHour. Very clear, and then Gwen Ifill asks him what practical value this finding will have in everyday life. His response: None.
So refreshing to hear a scientist defend the urge to satisfy mere curiosity about how the universe began. Among his musings in the post itself: “We tell stories about how the universe works, but we don’t simply tell any old stories that come to mind; we are dramatically constrained by experimental data and by consistency with the basic principles we think we do understand.”
And now, the multiverses
We get a nice, clear history of the theory-building in the decades before BICEP2, plus a brief summary of the findings and some implications, from Tom Levenson, who blogs at The Inverse Square. One of those implications is “That the idea of a multiverse — other patches of space time that underwent an inflationary episode to form island universes of their own — has now gained a boost (if one patch of space-time can inflate, so could others)….”
At National Geographic, multiverses are the central topic of Dan Vergano’s post. He observes, “in the models favored by the BICEP2 team’s observations, the process that inflates a universe looks just too potent to happen only once; rather, once a Big Bang starts, the process would happen repeatedly and in multiple ways . . . That means every kind of cosmos is out there in the aftermath of the Big Bang, from our familiar universe chock full of stars and planets to extravaganzas that encompass many more dimensions, but are devoid of such mundane things as atoms or photons of light.”
Multiverses are not an easy idea to get your brain around, but they help explain some cosmological puzzles, Vergano says. Such as why the universe we live in is a universe we can live in, a universe organized around laws of physics that permit biochemistry and so forth, and which makes possible life (or at least life-as-we-know-it.)
Chronic naysayer John Horgan, at SciAm’s Cross-Check, rejects multiverses on grounds that the hypothesis is both unscientific and immoral. Unscientific because multiverses “are totally imaginary and by definition can never be observed.” On immorality, he quotes himself reviewing Brian Greene’s 2011 book The Hidden Reality: “First, at a time when we desperately need science to help us solve our problems, it’s irresponsible for scientists as prominent as Greene to show such a blithe disregard for basic standards of evidence. Second, like religious visions of paradise, multiverses represent an escapist distraction from our world.”
The inflationary skeptics: Let us hope it is not a trick
The most potent skeptic is probably Horgan because his objections are couched in largely nontechnical language and so can be comprehended more widely. At that same Cross-Check post, he writes that he hopes the gravitational wave findings turn out to be true, “because cosmology and physics desperately need a jolt of energy.” But until several conditions are met, he remains doubtful about the inflationary theory.
The first of his conditions is, of course, confirmation of the BICEP2 data by other sources. Sean Carroll told Gwen Ifill that a number of groups will be releasing data on this point in the next couple of years, so we should know whether others agree with the BICEP2 findings pretty soon. Or don’t. Among other things Horgan wants to know is what mechanism drove this vast inflation and why only inflation can account for the gravitational wave findings.
Another skeptic is cosmologist Peter Coles, who blogs at In the Dark and has posted about the BICEP2 findings a number of times. I am too unlettered in this field to have an opinion about his critiques, except to note Coles saying he would place only an even-money bet that what BICEP2 has found is in fact a cosmological signal. He commends the researchers and likes the fact that they have posted their paper and data for all to peer review. He also praises social media’s response and links to the Facebook discussion of BICEP2. I haven’t studied it, but it looks pretty technical. Doesn’t sound like Facebook at all.
Still, Coles says, while the BICEP2 results are interesting, “it is far too earlier [sic] to even claim that they are cosmological, let alone to start talking about providing evidence for or against particular models of the early Universe. . . this is a measurement of such potential importance that I think we have to set the bar very high indeed when it comes to evidence.”
Even a developer of inflation theory, Andrei Linde, is not entirely convinced. At the New Yorker, Andrea DenHoed presents a video of Linde being told by one of the BICEP2 researchers that the telescope is backing up his theory. Linde says, “Let us hope it is not a trick. I always live with this feeling. What if I am tricked? What if I believe in this just because it is beautiful? What if . . .”