What Ranga Chary at the Caltech data center for the Planck telescope collaboration is claiming to have found is something different. (Chary has not responded to Gizmodo’s request for comment.) “They’re hunting for lions, and we’re hunting for polar bears,” Johnson told New Scientist. As reporter Joshua Sokol writes:

Instead of looking at the CMB itself, Chary subtracted a model of the CMB from Planck’s picture of the entire sky. Then he took away everything else, too: the stars, gas and dust. With our universe scrubbed away, nothing should be left except noise. But in a certain frequency range, scattered patches on the sky look far brighter than they should. If they check out, these anomalous clumps could be caused by cosmic fist-bumps: our universe colliding with another part of the multiverse.

These patches look like they come from the era a few hundred thousand years after the big bang when electrons and protons first joined forces to create hydrogen, which emits light in a limited range of colours. We can see signs of that era, called recombination, in the light from that early hydrogen. Studying the light from recombination could be a unique signature of the matter in our universe – and potentially distinguish signs from beyond.


That light is tough to spot, since it tends to blend in with the CMB. Chary found a few patches that were much brighter than expected. One possible explanation is that a collision with another universe led to extra protons and electrons in those patches. But it could also be noise that just looks like a signal.

It’s not Chary’s analysis that’s raising questions, it’s his interpretation of what those bright patches signify. David Spergel (Princeton University) told New Scientist that he thinks that dust might once again be the culprit and suggested to Sokol that physicists should seek out alternative explanation: “The dust properties are more complicated than we have been assuming, and I think this is a more plausible explanation.” Johns Hopkins’ Joseph Silk was harsher in his dismissal, calling Chary’s claim “completely implausible.”As for Johnson, he told Gizmodo that he will remain skeptical pending confirmation from independent analysis.


Even Chary cautions that his conclusion is still tentative, writing that “Unusual claims like evidence for alternate universes require a very high burden of proof.” And yet somehow all anyone outside of physics is hearing is this:

Look, I love the idea of a multiverse as much as the next person; it’s a fascinating research area with the potential for uncovering some very exciting new physics. But frankly, this paper doesn’t warrant the amount of press it’s been getting this week. It’s the first draft of a paper by a scientist at the Planck data center at Caltech (as opposed to an official paper from the full Planck collaboration). It’s been submitted to a reputable journal, but has yet to undergo any peer review, and while it’s an intriguing analysis, Johnson, for one, thinks acceptance for publication might prove difficult.


So why are we even talking about it? It’s only a story because people think the multiverse is cool. And it is. It really is. But it’s a disservice to Chary and the process of science to trumpet a discovery this early in the game.

UPDATE 11/7/15: Chary has responded briefly via email about the next step in confirming or disproving his hypothesis: “The updated version of the paper has a section on future directions. Simple tests can be done with existing facilities (ALMA/LMT spectroscopy), so I think we can pin it down in a couple of years. More detailed measurements have to wait for the next generation of facilities i.e., 15-20 yrs down the line.”



Chary, R. (2015) “Spectral variations of the sky: constraints on alternate universes,” arXiv.


Wainwright, Carroll et al. (2014) “Simulating the universe(s): from cosmic bubble collisions to cosmological observables with numerical relativity,” Journal of Cosmology and Astroparticle Physics 03: 030.

Wainwright, Carroll et al. (2014) “Simulating the universe(s) II: phenomenology of cosmic bubble collisions in full general relativity,” Journal of Cosmology and Astroparticle Physics 10: 024.


[Via arXiv and New Scientist]

Image courtesy of ESA and the Planck Collaboration.