Multiverse theory comes to life in a Cold Spot

It’s nice to see a close colleague getting some positive recognition and publicity, so I’ve been enjoying following the fresh spring of articles in the last 24 hours reporting on Tom Shanks' teams work on the CMB cold spot.

It’s been picked up by The Guardian, The Telegraph and the Metro, with the speculative idea as the Cold Spot as evidence for the Multiverse scenario in particular striking a chord given the turbulent political landscape of the last 12 months.

I’m not amazingly familiar with the science, but a reasonable summary is that we detect a very uniform signal of radio waves across the whole sky originating from the time of the Big Bang. This highly uniform signal contains tiny fluctuations relating to quantum effects in the early Universe. A number of years ago, a highly ambitious project by the name of WMAP measured these tiny fluctuations very precisely and found a strange anomaly that we now call the ‘Cold Spot’ — a vast area of the sky where the radiation showed the Universe to be anomalously cooler.

An overview of the survey from Mackenzie et al. (2017). The colour-contour background shows a map of the Universe in microwaves taken by Planck, showing the CMB cold spot (mostly dark blue region). Mackenzie et al. mapped the galaxy population within the black circles to search for super-voids (giant under-dense regions) in the galaxy distribution.

Since WMAPs results a decade ago, the explanation to the Cold Spot has continued to elude Cosmologists. One suggestion has been a super-void (very low numbers of galaxies across a large volume of space) in the area of sky where the Cold Spot is observed, affecting the Big Bang radiation as it travels through the Universe towards us. The Shanks team’s work (published in Mackenzie et al. 2017), mapped the distribution of galaxies in the Cold Spot region on the sky and what they’ve found is that the galaxies aren’t the cause of the Cold Spot - the numbers of galaxies in this patch of sky appears pretty much the same as elsewhere.

So where does that leave us? The Shanks team have speculated on the idea that his Cold Spot is the result of colliding Universes — another Universe exerting pressure on our own from outside somehow and causing a shift in the frequency of the radiation as it travels across our Universe. This is pretty exciting stuff, but difficult at this stage to take any further than a speculative idea.

It reminds me of an interesting article I recently read, arguing against jumping to exotic conclusions in science, when more mundane, familiar solutions are more probable. This, it is fair to say, very much falls within the exotic category, and there’s more than likely a relatively mundane answer to the Cold Spot anomaly. But the Shanks' group’s work is also an example of how important it is to have someone in the scientific community take an occasional gamble and explore the less-likely or exotic solutions to scientific problems.

First up, considering the exotic helps us challenge our preconceptions and biases. Dismissing out of hand something potentially exotic narrows our field of view and potentially inhibits progress.

Second, as a community its imperative to connect with the wider public, and exotic ideas, like the colliding Universes idea here, clearly resonate. We’re reliant on significant amounts of taxpayers money and its only too clear from Brexit that if you don’t make you’re value known, and connect positively with the public, the tide can very quickly turn against you. It’s a stark failing that for decades, UK politicians failed to put the effort into making Britain’s EU membership resonate and have relevance in the minds of voters, resulting in the public voting against the mainstream Westminster viewpoint.

Expressing a sentiment an old friend received from his supervisor — you don’t get the Nobel Prize by being mundane. So here’s to the exotic solutions. They have their place scattered amongst the mundane and obvious.

Link to the academic article: Mackenzie et al. (2017) — “ Evidence against a supervoid causing the CMB Cold Spot”

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