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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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Age verification rules won't just affect porn sites – they'll harm our ability to discuss sex

Relying on censorship to avoid talking about sex lets children down.

The British have a long history of censoring sex. In 1580, politician William Lambarde drafted the first bill to ban "licentious" and "hurtful... books, pamphlets, ditties, songs, and other works that promote the art of lascivious ungodly love". Last week, the UK government decided to have another crack at censorship, formally announcing that age verification for all online pornographic content will be mandatory from April 2018.

It is unclear at this point what this mandatory check will entail, but it's expected that you will need to submit your credit card details to a site before being allowed to access adult content (credit cards can’t be issued to under-18s).

The appointed regulator will almost certainly be the British Board of Film Classification who will have the authority to levy fines of up to £250,000 or shut down sites that do not comply. These measures are being directly linked to research conducted by the NSPCC, the Children’s Commissioner and the University of Middlesex in 2016, which surveyed more than 1,000 11 to 16-year-olds about viewing online pornography and found over half had accessed it. 

Digital minister Matt Hancock said age verification "means that while we can enjoy the freedom of the web, the UK will have the most robust internet child protection measures of any country in the world". And who can argue with that? No sane adult would think that it’s a good idea for children to watch hardcore pornography. And because we all agree kids should be watching Peppa Pig rather than The Poonies, the act has been waved through virtually unchallenged.

So, let’s put the issue of hardcore pornography to one side, because surely we are all in agreement. I’m asking you to look at the bigger picture. It’s not just children who will be censored and it’s not just Pornhub and Redtube which will be forced to age check UK viewers. This act will potentially censor any UK site that carries adult content, which is broadly defined by the BBFC as "that it was produced solely or principally for the purposes of sexual arousal".

I am a UK academic and research the history of sexuality. I curate the online research project, where academics, activists, artists and sex workers contribute articles on all aspects of sexuality in the hope of joining up conversations around sex that affect everyone. The site also archives many historical images; from the erotic brothel frescoes of Pompeii to early Victorian daguerreotypes of couples having sex. And yet, I do not consider myself to be a porn baron. These are fascinating and important historical documents that can teach us a great deal about our own attitudes to sex and beauty.

The site clearly signposts the content and asks viewers to click to confirm they are over 18, but under the Digital Economy Act this will not be enough. Although the site is not for profit and educational in purpose, some of the historical artefacts fit the definition of  "pornographic’" and are thereby liable to fall foul of the new laws.

And I’m not the only one; erotic artists, photographers, nude models, writers, sex shops, sex education sites, burlesque sites, BDSM sites, archivists of vintage erotica, and (of course) anyone in the adult industry who markets their business with a website, can all be termed pornographic and forced to buy expensive software to screen their users or risk being shut down or fined. I have contacted the BBFC to ask if my research will be criminalised and blocked, but was told "work in this area has not yet begun and so we are not in a position to advice [sic] you on your website". No one is able to tell me what software will need to be purchased if I am to collect viewers' credit card details, how I would keep them safe, or how much this would all cost. The BBFC suggested I contact my MP for further details. But, she doesn’t know either.

Before we even get into the ethical issues around adults having to enter their credit card details into a government database in order to look at legal content, we need to ask: will this work? Will blocking research projects like mine make children any safer? Well, no. The laws will have no power over social media sites such as Twitter, Snapchat and Periscope which allow users to share pornographic images. Messenger apps will still allow users to sext, as well as stream, send and receiving pornographic images and videos. Any tech savvy teenager knows that Virtual Private Network (VPN) software will circumvent UK age verification restrictions, and the less tech savvy can always steal their parents' credit card details.

The proposed censorship is unworkable and many sites containing nudity will be caught in the crossfire. If we want to keep our children "safe" from online pornography, we need to do something we British aren’t very good at doing; we need to talk openly and honestly about sex and porn. This is a conversation I hope projects like mine can help facilitate. Last year, Pornhub (the biggest porn site in the world) revealed ten years of user data. In 2016, Brits visited Pornhub over 111 million times and 20 per cent of those UK viewers are women. We are watching porn and we need to be open about this. We need to talk to each other and we need to talk to our kids. If you’re relying on government censorship to get you out of that tricky conversation, you are letting your children down.

The NSPCC report into children watching online pornography directly asked the participants about the effectiveness of age verification, and said the children "pointed out its limitations". When asked what intervention would most benefit them, this was the overwhelming response: "Whether provided in the classroom, or digitally, young people wanted to be able to find out about sex and relationships and about pornography in ways that were safe, private and credible." I suggest we listen to the very people we are trying to protect and educate, rather than eliminate. 

Dr Kate Lister researches the history of sexuality at Leeds Trinity University