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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Banning Britain First is great, but we can’t rely on Facebook to save us from racist populism

There are darker niches on social media, and wider social pressures behind them. 

Facebook's biggest UK political party is no more. The social media site has banned Britain First, the fringe far-right political party, which, despite having no elected MPs, MEPs or even councillors, amassed more than two million Likes on its page.

The ban is the most visible move to date that social networks are keen to be seen to be taking action against extremist content among a political backlash against the tech giants from countries across Europe, and the US itself.

It follows a similar ban of the party’s leaders from Twitter earlier this year, after President Donald Trump retweeted anti-Muslim videos posted by Britain First’s deputy leader.

Facebook’s move takes out one of the most powerful distribution channels for anti-Muslim content online. The page used quite sophisticated social media strategies to spread its message, posting inoffensive patriotic imagery – support our armed forces; oppose animal cruelty – to reach a wide audience, while thrpwing more explicit anti-Muslim posts into the mix.

This blend of content was itself dangerous, serving to normalise anti-Muslim views among a huge audience of casual Facebook users, many of whom were older adults. Last year, we analysed more than one million Likes on Britain First posts – about six weeks’ worth – for BuzzFeed News, finding that, while relying on a hardcore of several hundred users, the page worked successfully to reach a large pool of casual viewers, some of whom would likely be unaware of the group’s motivations.

This made the public Britain First page a powerful tool for reaching potentially sympathetic would-be recruits, but also in generating an active core membership – a power Facebook clearly recognised with its decision to ban the group.

But we shouldn’t be fooled into thinking we can tackle the rise of populism with a scattergun technological fix. The social pressures behind the popularity of such groups won’t change, and so, without clear policies, Facebook risks political incoherence and accusations of censorship. 

Britain First and the material they post have been extensively covered in the mainstream media for the past 18 months, yet they were allowed to continue posting more. Facebook must explain why such posts were considered acceptable over this period, before suddenly becoming unacceptable now. The far right is talented at exploiting “censorship” to its own advantage, claiming it is speaking the truths that those in power do not want to hear.

That doesn’t mean the group should have been allowed to continue on Facebook, but it does mean the limitations of speech are on each social network should be set out clearly and in detail.

This is particularly important because Britain First’s Facebook presence was just the most visible part of a far-right Facebook ecosystem – the nastiest content is much harder to see, hidden away in closed groups which admit new users by invitation only.

Because such groups – which often go by names such as “NO SHARIA LAW” or similar – are hidden, it is much harder to track their activity and their membership, but they number in the hundreds and some have thousands or hundreds of thousands of members. While Britain First might be the visible portion of anti-Muslim Facebook content, its these groups that likely pose the larger challenges, especially as it is not in the open where it can be challenged.

Going further, tackling the public groups helps disrupt the feed of users who could be radicalised into becoming active members of the far-right, but could serve to further radicalise those already within the private groups. There is a delicate balancing act to be tackled, and one which serves to show how important Facebook is now in public policy debates: in practical terms, a US technology company is now more influential than government policy when it comes to online extremism.

It will be a welcome relief to many that Britain First content won’t pollute their feeds any longer – but it highlights how much power we have delegated, how much Facebook can shape our rules, and how tech is running ahead of our laws and our own social decisions.

Banning Britain First from Facebook might be a move many of us like – but we shouldn’t rely on big tech to save us from populism, and its accompanying tide of racism. These are conversations we should be having – and battles we should be fighting – as a society.

James Ball is an award-winning freelance journalist who has previously worked at the Guardian and Buzzfeed. He tweets @jamesrbuk