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How harnessing the strangeness of light allows science to shine

From eyecare to creating the coldest thing in the universe, lasers show science at its most illuminating.

A lazer show at Los Angeles' Staples Center. Photo: Bruce Bennett/Getty Images


There’s nothing like winter gloom to make you appreciate the qualities of light. But rarely appreciated is what a puzzle they present.

Physicists still don’t know what light is. You can think of it as either a wave or a particle, because it is both and neither. A century of physics experiments has shown that it hits our eyes in packets of energy known as photons. More than 100 years of experiments have also shown, however, that it operates in continuous waves, like ripples on water. We have been trying to describe what light is since the days of Isaac Newton and we still have no clear understanding.

The quantum properties of light make things worse: they show that we really don’t understand how the universe works. In Paris this month, at the opening ceremony for the Unesco International Year of Light, the French researcher Alain Aspect will explain how an experiment on light he first carried out in 1982 destroyed our conception of what is real.

Aspect’s experiment led to two extraordinary conclusions. First, it showed that certain properties of photons are generated at random by the act of measuring them. The implication is that the universe is random at heart – not every effect has a cause. The second is that you can affect the properties of a distant photon in ways that defy all conventional notions of space and time.

For all the philosophical conundrums it creates, we have harnessed the strangeness of light with aplomb. Take the laser, which relies on the quantum properties of photons. Initially it was a means of “light amplification”: adding energy for tasks such as cutting or burning. But, oddly, its most exciting application in physics now is in refrigeration.

When the Nobel laureate William Phillips gives his plenary lecture at the Paris ceremony, he will no doubt mention his work using laser energy to cool atoms down. By tuning their lasers’ energy carefully, Phillips and his colleagues have learned how to extract energy from atoms – to the point where, while the lasers remain switched on, the bath of atoms becomes the coldest thing in the universe.

Another lecturer (and Nobel laureate), Ahmed Zewail, will discuss the process of chopping up laser beams into “femtosecond” pulses a quadrillionth of a second long. This technique enables physicists to take photographs of chemical reactions as they happen. When applied to biology, femtosecond photography allows us to watch biomolecules create and break the bonds between each other. This is especially valuable in trying to understand the mechanisms of vision and photosynthesis, in which plants turn sunlight into energy.

As such, it is fitting that Zewail’s talk will be followed by presentations from projects that are using much older science to help human beings in both of those fields.

The science in question is most closely associated with Newton: it is the bending, or refraction, of light. The Liter of Light scheme teaches people in developing countries how to incorporate plastic bottles of water into their roofs, channelling sunlight into windowless homes and saving on the cost of electric lighting.

Refraction also powers spectacles, an innovation we take for granted in the west. According to the World Health Organisation, 150 million people worldwide cannot work or educate themselves because of defective eyesight. The OneDollarGlasses project is eating away at that figure by training low-cost opticians. A combination of pre-ground polycarbonate lenses and simple spring steel frames is changing lives around the world. Whether in hi or low tech, we have proved that we don’t have to understand light to put it to work. 

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 16 January 2015 issue of the New Statesman, The Jihadis Among Us

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A quote-by-quote analysis of how little Jeremy Hunt understands technology

Can social media giants really implement the health secretary’s sexting suggestions? 

In today’s “Did we do something wrong? No, it was social media” news, Health Secretary Jeremy Hunt has argued that technology companies need to do more to prevent sexting and cyber-bullying.

Hunt, whose job it is to help reduce the teenage suicide rate, argued that the onus for reducing the teenage suicide rate should fall on social media companies such as Facebook and Twitter.

Giving evidence to the Commons Health Committee on suicide prevention, Hunt said: “I think social media companies need to step up to the plate and show us how they can be the solution to the issue of mental ill health amongst teenagers, and not the cause of the problem.”

Pause for screaming and/or tearing out of hair.

Don’t worry though; Hunt wasn’t simply trying to pass the buck, despite the committee suggesting he direct more resources to suicide prevention, as he offered extremely well-thought out technological solutions that are in no way inferior to providing better sex education for children. Here’s a quote-by-quote analysis of just how technologically savvy Hunt is.


“I just ask myself the simple question as to why it is that you can’t prevent the texting of sexually explicit images by people under the age of 18…”

Here’s Hunt asking himself a question that he should be asking the actual experts, which is in no way a waste of anybody’s time at all.

“… If that’s a lock that parents choose to put on a mobile phone contract…”

A lock! But of course. But what should we lock, Jeremy? Should teenager’s phones come with a ban on all social media apps, and for good measure, a block on the use of the camera app itself? It’s hard to see how this would lead to the use of dubious applications that have significantly less security than giants such as Facebook and Snapchat. Well done.

“Because there is technology that can identify sexually explicit pictures and prevent it being transmitted.”

Erm, is there? Image recognition technology does exist, but it’s incredibly complex and expensive, and companies often rely on other information (such as URLs, tags, and hashes) to filter out and identify explicit images. In addition, social media sites like Facebook rely on their users to click the button that identifies an image as an abuse of their guidelines, and then have a human team that look through reported images. The technology is simply unable to identify individual and unique images that teenagers take of their own bodies, and the idea of a human team tackling the job is preposterous. 

But suppose the technology did exist that could flawlessly scan a picture for fleshy bits and bobs? As a tool to prevent sexting, this still is extremely flawed. What if two teens were trying to message one another Titian’s Venus for art or history class? In September, Facebook itself was forced to U-turn after removing the historical “napalm girl” photo from the site.

As for the second part of Jezza’s suggestion, if you can’t identify it, you can’t block it. Facebook Messenger already blocks you from sending pornographic links, but this again relies on analysis of the URLs rather than the content within them. Other messaging services, such as Whatsapp, offer end-to-end encryption (EE2E), meaning – most likely to Hunt’s chagrin – the messages sent on them are not stored nor easily accessed by the government.

“I ask myself why we can’t identify cyberbullying when it happens on social media platforms by word pattern recognition, and then prevent it happening.”

Jeremy, Jeremy, Jeremy, Jeremy, can’t you spot your problem yet? You’ve got to stop asking yourself!

There is simply no algorithm yet intelligent enough to identify bullying language. Why? Because we call our best mate “dickhead” and our worst enemy “pal”. Human language and meaning is infinitely complex, and scanning for certain words would almost definitely lead to false positives. As Labour MP Thangam Debbonaire famously learned this year, even humans can’t always identify whether language is offensive, so what chance does an algorithm stand?

(Side note: It is also amusing to imagine that Hunt could even begin to keep up with teenage slang in this scenario.)

Many also argue that because social media sites can remove copyrighted files efficiently, they should get better at removing abusive language. This is a flawed argument because it is easy to search for a specific file (copyright holders will often send social media giants hashed files which they can then search for on their databases) whereas (for the reasons outlined above) it is exceptionally difficult for algorithms to accurately identify the true meaning of language.

“I think there are a lot of things where social media companies could put options in their software that could reduce the risks associated with social media, and I do think that is something which they should actively pursue in a way that hasn’t happened to date.”

Leaving aside the fact that social media companies constantly come up with solutions for these problems, Hunt has left us with the burning question of whether any of this is even desirable at all.

Why should he prevent under-18s from sexting when the age of consent in the UK is 16? Where has this sudden moral panic about pornography come from? Are the government laying the ground for mass censorship? If two consenting teenagers want to send each other these aubergine emoji a couple of times a week, why should we stop them? Is it not up to parents, rather than the government, to survey and supervise their children’s online activities? Would education, with all of this in mind, not be the better option? Won't somebody please think of the children? 

“There is a lot of evidence that the technology industry, if they put their mind to it, can do really smart things.

Alas, if only we could say the same for you Mr Hunt.

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