I'm looking out of my office window. I see one solitary cloud in a typically blue Californian sky. If I concentrate really hard, the cloud kinda looks like a rabbit. Actually, now I'm seeing that rabbit, as the wind slowly morphs the cotton candy-like texture, it looks more and more like a rabbit. It's a crouching rabbit! Eating a tuft of grass right next to its fluffy nose! Where's my camera? Damn. It's stopped looking like a rabbit. It's just a cloud.
Granted, I think I might have had one-too-many coffees today, but with a little imagination, it's not hard to make a shape out of something apparently random. And it would appear that something similar - albeit with details grossly more complex - has happened in a recent piece of fascinating cosmology research.
Last week, the world's media tried to make sense out of an unpublished paper written by Oxford University physicist Roger Penrose and co-author Vahe Gurzadyan from the Yerevan Physics Institute in Armenia.
Basically, the two theoretical physicists did some analysis of the cosmic microwave background radiation (CMBR) - a relic "echo" of the radiation generated shortly after the Big Bang - and found an eerie pattern in the slight temperature "anisotropies" of the signal.
Cosmologists have used this Big Bang remnant to understand the history and very nature of our Universe, it would be truly bizarre if a pattern were to be discovered in this faint, apparently random microwave "noise." But this is exactly what Penrose and Gurzadyan were suggesting: they'd found a circular pattern in the CMBR. What's more, they proposed a theory as to what these ripples might be.
Could they be signals from universes past? Could they be the leakage of gravitational waves caused by the cataclysmic collisions of supermassive black holes before the Big Bang? Could this finding rock the foundations of Big Bang theory, inflation and the very origin of our Universe?
According to the authors of two new papers (2.1305">1,2) submitted to arXiv, the answer is: No.
Although the hypothesis presented by Penrose and Gurzadyan is certainly interesting, according to cosmologist Sean Carroll, they're just plain wrong.
The authors of these new papers are respected scientists who work with CMBR data on a daily basis. Although world renowned physicists, Penrose and Gurzadyan are not known for their work with CMBR data, and therefore may have misinterpreted what they are looking at.
From Sean at Cosmic Variance:
"The basic message is simple: sure, you can find some circles in the sky if you look there. But they are simply what you would expect from random alignments, not a new signal over and above the usual predictions. The authors [of the rebuttal papers] are respected CMB analyzers, and I strongly suspect that they are correct. Which reminds us of an important lesson: analyzing the CMB is hard! It's a very messy universe out there, and if you don't take every single source of error correctly into account, you can convince yourself of all sorts of things." - Sean Carroll.
Could it be that Penrose and Gurzadyan did the cosmological equivalent of looking too hard at clouds trying to make rabbit shapes? Possibly.
In one of the rebuttal papers written by Adam Moss, Douglas Scott and James P. Zibin ("No evidence for anomalously low variance circles on the sky," arXiv:1012.1305v1), they pretty much allude to a similar "cloud bunny" conclusion:
"In other words, properly simulated Gaussian CMB data contain just the sorts of variations claimed. Gurzadyan & Penrose have not found evidence for pre-Big Bang phenomena, but have simply re-discovered that the CMB contains structure."
Given enough detail, random or otherwise, you can construct any pattern you're looking for.
Of course, I need to point out the obvious here, Gurzadyan and Penrose did not publish their work. The "circles in the CMB" research was submitted to the arXiv pre-print service, bypassing any peer review before publication to a major scientific journal. So, rather than changing the course of mainstream cosmology, they wanted to get their ideas out to the community and perhaps generate some media waves along the way.
As it turns out, established CMBR analysts have shot down Gurzadyan and Penrose's analysis, pointing out that they have simply "re-discovered" artifacts in the cosmic microwave background anisotropies.
In a short period, we've seen science at work on a very public stage. A controversial hypothesis has been put forward and before it could even be tested as a theory, scientists with a better insight have proven why this hypothesis - while interesting - is ultimately wrong. This is what science is all about, and it is no bad thing.
That said, it doesn't mean Penrose's underlying "conformal cyclic cosmology" (CCC) theory is wrong (for more on this, read my previous article on the subject), it just means more robust evidence is needed to topple our current theories on the birth of the Universe.
Still, as I mentioned before, wouldn't it be epic if a real Stargate Universe-style pattern was found in the CMBR?
Image: A WMAP image of temperature anisotropies in the CMBR (NASA/WMAP) plus a rabbit added by me (Photoshop has a rabbit shape, who knew!)