Dark skies: a view of the milky way during a meteor shower, Myanmar. Photo: Getty
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Dark energy vs dark matter: a battle of two cosmic monsters

Michael Brooks’s Science Column.

It might be the most prestigious journal in physics, but the Physical Review Letters is no good at teasers. Early in November it published a paper entitled: Indications of a Late-Time Interaction in the Dark Sector. Hardly a great headline for what should have been, in the style of Alien v Predator, “Dark Matter v Dark Energy” – a story of two cosmic monsters locked in eternal conflict.

We believe these monsters exist, but we haven’t seen either of them and we know very little about them. We have suspected the existence of dark matter since 1933, when a Swiss astronomer noticed something odd about the way galaxy clusters spin. They looked like they were being held together by the gravitational pull of invisible matter, which he duly named dark matter. We have been trying to see the stuff ever since, to no avail.

Dark energy is a more recent idea. It, too, comes from astronomical observations, this time of supernovae. A 1998 analysis of the light from these stellar explosions suggested that not only is the universe expanding, but this expansion is getting faster all the time. That can only happen with the help of energy from some unknown source – hence dark energy.

Together, dark energy and dark matter make up 96 per cent of the universe. Now, it turns out, dark energy may be consuming the dark matter.

The discovery came from more observations: this time, of the rate at which cosmic structures form. Dark matter seeds galaxy formation, but galaxies aren’t forming as fast as we would expect. This would make sense if dark matter were disappearing from the universe, but various straightforward explanations for why that might occur have failed to correspond with the observed facts. Now a team of British and Italian researchers has created a computer model that does match the observations. Critical to its success is the idea that dark matter is slowly being converted to dark energy.

According to the simulation, the ingestion of dark matter would be a relatively recent phenomenon, beginning roughly eight billion years ago. If it is really happening, it is important to understand, because our attempts to chart the history of the universe depend on dark matter’s role in forming cosmic structures.

Working from observations of the cosmic microwave background radiation, which came into being roughly 300,000 years after the Big Bang, researchers have shown that the radiation’s distribution through the universe would have seeded long filaments of dark matter. The gravitational pull of these filaments attracted the first atoms of normal matter, gradually creating stars and galaxies in long strings. This is the kind of structure we see now.

Yet if dark energy is slowly taking over from dark matter our previous calculations of cosmic history will have to be corrected. And intriguingly (spoiler alert), it will change our predictions. If dark energy is consuming dark matter, the universe will become dominated by dark energy more quickly than previously thought. That will precipitate an inglorious finale in which dark energy’s repulsive power pushes everything interesting away from us.

Eventually, all the other galaxies will be so far away, and receding so fast, that their light will never reach what remains of our Milky Way. Nearby stars will burn out. Our sun is expected to end its life as a huge single crystal of carbon: a dark diamond in the sky, with no surrounding starlight to make it sparkle.

Afterwards, all the atoms will drift apart and then the fundamental particles of matter will slowly decay to nothing. It’s not a Hollywood ending, but don’t complain that you weren’t warned. 

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 27 November 2014 issue of the New Statesman, The rise of the insurgents

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Did your personality determine whether you voted for Brexit? Research suggests so

The Online Privacy Foundation found Leave voters were significantly more likely to be authoritarian and conscientious. 

"Before referendum day, I said the winners would be those who told the most convincing lies," Paul Flynn, a Labour MP, wrote in these pages. "Leave did." The idea that those who voted for Brexit were somehow manipulated is widely accepted by the Remain camp. The Leave campaign, so the argument goes, played on voters' fears and exploited their low numeracy. And new research from the Online Privacy Foundation suggests this argument may, in part at least, be right. 

Over the last 18 months the organisation have researched differences in personality traits, levels of authoritarianism, numeracy, thinking styles and cognitive biases between EU referendum voters. The organisation conducted a series of studies, capturing over 11,000 responses to self-report psychology questionnaires and controlled experiments, with the final results scheduled to be presented at the International Conference on Political Psychology in Copenhagen in October 2017.

The researchers questioned voters using the "Five Factor Model" which consists of five broad personality traits - Openness, Conscientiousness, Extraversion, Agreeableness and Neuroticism. They also considered the disposition of authoritarianism (it is not considered a personality trait). Authoritarians have a more black and white view of the world around them, are more concerned with the upkeep of established societal traditions and have a tendency to be less accepting of outsiders. 

So what did they uncover? Participants expressing an intent to vote to leave the EU reported significantly higher levels of authoritarianism and conscientiousness, and lower levels of openness and neuroticism than voters expressing an intent to vote to remain. (Conscientiousness is associated with dependability, dutifulness, focus and adherence to societal norms in contrast to disorganisation, carelessness and impulsivity.)

Immigration in particular seems to have affected voting. While authoritarians were much more likely to vote Leave to begin with, those who were less authoritarian became increasingly likely to vote Leave if they expressed high levels of concern over immigration. These findings chime with research by the Professors Marc Hetherington and Elizabeth Suhay, which found that Americans became susceptible to "authoritarian thinking" when they perceived a grave threat to their safety. 

Then there's what you might call the £350m question - did Leave voters know what they were voting for? When the Online Privacy Foundation researchers compared Leave voters with Remain voters, they displayed significantly lower levels of numeracy, reasoning and appeared more impulsive. In all three areas, older voters performed significantly worse than young voters intending to vote the same way.

Even when voters were able to interpret statistics, their ability to do so could be overcome by partisanship. In one striking study, when voters were asked to interpret statistics about whether a skin cream increases or decreases a rash, they were able to interpret them correctly roughly 57 per cent of the time. But when voters were asked to interpret the same set of statistics, but told they were about whether immigration increases or decreases crime, something disturbing happened. 

If the statistics didn't support a voter's view, their ability to correctly interpret the numbers dropped, in some cases, by almost a half. 

Before Remoaners start to crow, this study is not an affirmation that "I'm smart, you're dumb". Further research could be done, for example, on the role of age and education (young graduates were far more likely to vote Remain). But in the meantime, there is a question that needs to be answered - are political campaigners deliberately exploiting these personality traits? 

Chris Sumner, from the Online Privacy Foundation, warns that in the era of Big Data, clues about our personalities are collected online: "In the era of Big Data, these clues are aggregated, transformed and sold by a burgeoning industry."

Indeed, Cambridge Analytica, a data company associated with the political right in the UK and US, states on its website that it can "more effectively engage and persuade voters using specially tailored language and visual ad combinations crafted with insights gleaned from behavioral understandings of your electorate". It will do so through a "blend of big data analytics and behavioural psychology". 

"Given the differences observed between Leave and Remain voters, and irrespective of which campaign, it is reasonable to hypothesize that industrial-scale psychographic profiling would have been a highly effective strategy," Sumner says. By identifying voters with different personalities and attitudes, such campaigns could target "the most persuadable voters with messages most likely to influence their vote". Indeed, in research yet to be published, the Online Privacy Foundation targeted groups with differing attitudes to civil liberties based on psychographic indicators associated with authoritarianism. The findings, says Sumner, illustrate "the ease with which individuals' inherent differences could be exploited". 

Julia Rampen is the digital news editor of the New Statesman (previously editor of The Staggers, The New Statesman's online rolling politics blog). She has also been deputy editor at Mirror Money Online and has worked as a financial journalist for several trade magazines. 

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