Dynamite with a laser beam: artist Yvette Mattern's Global Rainbow in Whitley Bay, 2012. Photo: Getty
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Firing lasers into a box made of gold – the race to turn light particles into matter

This could prove a neater way to investigate the fundamental building blocks of nature than examining the debris created by high-energy particle collisions.

By the time you read this, someone might already have done it. The publication of a report in May marked the beginning of the race to turn light into matter. Once the race is won, we could enter a new era in particle physics experiments but the real prize is far more valuable. This is about understanding the roots of our existence.

The idea of creating particles from light was dreamed up in 1934. The basic procedure is to smash together two photons, which are bundles of light energy. Calculations showed that, if done correctly, two particles of matter would magically appear in place of the light. The procedure invokes Albert Einstein’s equation E=mc2. The same equation lies behind the release of energy from nuclear fission. Not only do we now have atomic bombs but, it turns out, we also have the technology to take things in the opposite direction.

A team of physicists from Imperial College London has worked out the details. To collide photons to make matter, first fire a laser into an empty box made of gold. This creates a sea of photons with enormous amounts of energy. At the same time, accelerate a beam of electrons to nearly the speed of light using another high-power laser. Slam those electrons into a slab of gold and they will release a stream of photons to collide with the sea of photons in the gold box. The result will be the creation of electrons – one of the building blocks of matter – and positrons, the electron’s antimatter particle.

Now that it’s clear how to do it, there is little stopping scientists from performing this astonishing trick tomorrow. There are many facilities around the world that could string the various necessary technologies together.

What’s more, ramp up the energies of the lasers and it should eventually be possible to create bigger, heavier particles out of light. This could prove a neater way to investigate the fundamental building blocks of nature than examining the debris created by high-energy particle collisions in machines such as Cern’s Large Hadron Collider. Yet the big spin-off of such feats is in firing the imagination. This is science for the soul.

What this branch of physics teaches us is that our everyday intuition is not to be trusted. That matter and energy are two forms of the same stuff is entirely counter-intuitive. We have long given intellectual assent to the idea but it is so far removed from our day-to-day experience of the world that it may always seem implausible.

This interplay of light and matter is the rock on which the modern world is built. The silicon microchips in your smartphone and your laptop – maybe even your toaster – rely on the fluidity of matter. The microscopic electrical switches they contain work only because electrons are both matter and energy, flowing from one existence to the other as circumstances dictate.

Equally, we are solidly matter in our experience, yet we now know that we are made of stuff that can, in the right circumstances, be transformed into flashes of energy. That energy could, given sufficiently advanced technology, be turned back into us.

In some ways, it is a lesson about our impermanence but it is also a glimpse of our extraordinary gifts. We are matter that began its existence 14 billion years ago as a flash of primordial light. And now, that matter has learned the first step in repeating the process of its creation. For all the conflicts, disasters and alarming election results that human beings generate, we should still be proud of our species.

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 28 May 2014 issue of the New Statesman, The elites vs the people

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Don’t shoot the messenger: are social media giants really “consciously failing” to tackle extremism?

MPs today accused social media companies of failing to combat terrorism, but just how accurate is this claim? 

Today’s home affairs committee report, which said that internet giants such as Twitter, Facebook, and YouTube are “consciously failing” to combat extremism, was criticised by terrorism experts almost immediately.

“Blaming Facebook, Google or Twitter for this phenomenon is quite simplistic, and I'd even say misleading,” Professor Peter Neumann, an expert on radicalisation from Kings College London, told the BBC.

“Social media companies are doing a lot more now than they used to - no doubt because of public pressure,” he went on. The report, however, labels the 14 million videos Google have removed in the last two years, and the 125,000 accounts Twitter has suspended in the last one, a “drop in the ocean”.

It didn’t take long for the sites involved to refute the claims, which follow a 12-month inquiry on radicalisation. A Facebook spokesperson said they deal “swiftly and robustly with reports of terrorism-related content”, whilst YouTube said they take their role in combating the spread of extremism “very seriously”. This time last week, Twitter announced that they’d suspended 235,000 accounts for promoting terrorism in the last six months, which is incidentally after the committee stopped counting in February.

When it comes to numbers, it’s difficult to determine what is and isn’t enough. There is no magical number of Terrorists On The Internet that experts can compare the number of deletions to. But it’s also important to judge the companies’ efforts within the realm of what is actually possible.

“The argument is that because Facebook and Twitter are very good at taking down copyright claims they should be better at tackling extremism,” says Jamie Bartlett, Director of the Centre for the Analysis of Social Media at Demos.

“But in those cases you are given a hashed file by the copyright holder and they say: ‘Find this file on your database and remove it please’. This is very different from extremism. You’re talking about complicated nuanced linguistic patterns each of which are usually unique, and are very hard for an algorithm to determine.”

Bartlett explains that a large team of people would have to work on building this algorithm by trawling through cases of extremist language, which, as Thangam Debonnaire learned this month, even humans can struggle to identify.  

“The problem is when you’re dealing with linguistic patterns even the best algorithms work at 70 per cent accuracy. You’d have so many false positives, and you’d end up needing to have another huge team of people that would be checking all of it. It’s such a much harder task than people think.”

Finding and deleting terrorist content is also only half of the battle. When it comes to videos and images, thousands of people could have downloaded them before they were deleted. During his research, Bartlett has also discovered that when one extremist account is deleted, another inevitably pops up in its place.

“Censorship is close to impossible,” he wrote in a Medium post in February. “I’ve been taking a look at how ISIL are using Twitter. I found one user name, @xcxcx162, who had no less than twenty-one versions of his name, all lined up and ready to use (@xcxcx1627; @xcxcx1628, @xcxcx1629, and so on).”

Beneath all this, there might be another, fundamental flaw in the report’s assumptions. Demos argue that there is no firm evidence that online material actually radicalises people, and that much of the material extremists view and share is often from mainstream news outlets.

But even if total censorship was possible, that doesn’t necessarily make it desirable. Bartlett argues that deleting extreme content would diminish our critical faculties, and that exposing people to it allows them to see for themselves that terrorists are “narcissistic, murderous, thuggish, irreligious brutes.” Complete censorship would also ruin social media for innocent people.

“All the big social media platforms operate on a very important principal, which is that they are not responsible for the content that is placed on their platforms,” he says. “It rests with the user because if they were legally responsible for everything that’s on their platform – and this is a legal ruling in the US – they would have to check every single thing before it was posted. Given that Facebook deals with billions of posts a day that would be the end of the entire social media infrastructure.

“That’s the kind of trade off we’d be talking about here. The benefits of those platforms are considerable and you’d be punishing a lot of innocent people.”

No one is denying that social media companies should do as much as they can to tackle terrorism. Bartlett thinks that platforms can do more to remove information under warrant or hand over data when the police require it, and making online policing 24/7 is an important development “because terrorists do not work 9 to 5”. At the end of the day, however, it’s important for the government to accept technological limitations.

“Censorship of the internet is only going to get harder and harder,” he says. “Our best hope is that people are critical and discerning and that is where I would like the effort to be.” 

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