Egos and intensity in the search for dark matter

Voices in the dark.

In the next few weeks, the world’s most sensitive dark matter detector will begin its operations under Italy’s Gran Sasso mountain. This seems a good time to point out that it is sharing the mountain with a detector that may already have found some. What a shame, then, that what might one day be viewed as a historic result has been mired in petty name-calling.

We’ve been looking for dark matter since 1933, when the astronomer Fritz Zwicky pointed out that clusters of galaxies move in ways that seemingly defy the laws of physics. The movement made sense only if the clusters were experiencing a gravitational pull from some invisible stuff nearby.

For various reasons, mostly to do with other astronomers not liking Zwicky very much, we’ve been searching for dark matter seriously only since the 1970s. During those four decades, there has been a series of pronouncements about its discovery being only a decade away. It might now be time to take those pronouncements a little more seriously: lately, the sensitivity of detectors has been improving tenfold every two years. We must surely be on the verge of finally nailing down the existence of dark matter. If we haven’t already, that is.

Dark matter doesn’t just hold gravity clusters together – it’s everywhere. It’s right here on earth, for instance: billions of dark matter particles fly through your body every second. You won’t feel them and they won’t harm you. They don’t interact much with the stuff of our everyday reality, which is what has made them so hard to detect.

While we don’t have any concrete detections of single particles, we do seem to have a discernible signal from passing through clouds of dark matter. It was first spotted by the DAMA dark matter detector, which is based, like the new DarkSide-50 detector, deep under the mountains at Gran Sasso. The rock covering them protects the instruments from distracting sources of noise.

In 2008, DAMA’s operators announced that they had identified a signal that rose and faded with the seasons. It might have been ignored, except that this is exactly what Katherine Freese predicted for a dark matter signal in 1986. She said that the intensity of dark matter detections should depend on the time of year, because as the earth whirls round the sun and the sun moves through the Milky Way, the amount of dark matter hitting the detectors will ebb and flow. It’s rather like the difference between walking into wind-driven rain, then turning and walking the other way. In June, dark matter hits Planet Earth full in the face; in December, it’s at our back.

So, it was pretty exciting that DAMA’s detector saw this predicted pattern. It was even more exciting when another detector, CoGeNT, based in a deep underground mine in Minnesota, also saw it. It’s a shame that a third detector, Xenon, didn’t.

Xenon is also in the Gran Sasso mine and there is no love lost between the leaders of these two research efforts. CoGeNT’s Juan Collar has called Xenon’s science “pure, weapons-grade balonium”. Not content with antagonising his peers, Collar has also accused the DAMA project of “cheapening the level of our discourse to truly imbecilic levels”.

Finding dark matter is proving to be astonishingly difficult and everyone knows there’s a Nobel prize at stake, so it’s not surprising that the claws are out.

Anyway, welcome to the fray, DarkSide-50; there is definitely room for more players in this competition. Whether there is room for more egos, however, is another matter.

Inside the DarkSide-50 experiment.

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 18 February 2013 issue of the New Statesman, Iraq: ten years on

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The internet dictionary: what is astroturfing?

Yes, like the fake grass.

Thanks to the internet, there are a lot of new words. You’re most likely up to speed with your LOLs and OMGs, which became Oxford English Dictionary-worthy in 2011 (LOL OMG if you’re not). But words emerge constantly, and it can be hard to keep track of them. This is what this column is for. Every week, I’ll define a word that is crucial to understanding the internet, starting with “astroturfing” – like the fake grass.

To astroturf is to mask the author of a message to make it appear to have come from the grass roots. Messages created by brands, politicians and even the military are disguised as comments made by the public. The practice existed before the web – the term is thought to have been coined in 1985 by a US senator who received a “mountain” of letters from insurance companies posing as the public – but the internet has propelled it to new, disturbing heights.

“GIRLS U NEED TO READ THIS,” reads a tweet by a handsome teenage boy named Ashton, who tweets the same words day after day, followed by crying and heart emojis. Ashton lives to promote the book of a 19-year-old self-published author from Sheffield – or, at least, he would, if he lived at all. Ashton is fake, a profile designed to make the book seem popular. Many teenage girls have been duped by this. One told me: “I felt very cheated out of my money and my time.”

It has been estimated that a third of all consumer reviews online are fake. But it doesn’t end with bad books. In China, the “50 Cent Army” are astroturfers who are allegedly paid a small fee for each positive post they write about the Chinese Communist Party. And in 2011, it emerged that the US military was developing an “online persona management service” to spread pro-American messages, allowing one person to manage multiple online identities.

We would be foolish to assume that our own democracy is immune. Much was written about how the Tories used targeted social media adverts at the last election, and it is easy to see how astroturfing could transform our political landscape for ever. 

Amelia Tait is a technology and digital culture writer at the New Statesman.

This article first appeared in the 10 August 2017 issue of the New Statesman, France’s new Napoleon