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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

Flickr: B.S.Wise/YouTube
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Extremist ads and LGBT videos: do we want YouTube to be a censor, or not?

Is the video-sharing platform a morally irresponsible slacker for putting ads next to extremist content - or an evil, tyrannical censor for restricting access to LGBT videos?

YouTube is having a bad week. The Google-owned video-sharing platform has hit the headlines twice over complaints that it 1) is not censoring things enough, and 2) is censoring things too much.

On the one hand, big brands including Marks & Spencer, HSBC, and RBS have suspended their advertisements from the site after a Times investigation found ads from leading companies – and even the UK government – were shown alongside extremist videos. On the other, YouTubers are tweeting #YouTubeIsOverParty after it emerged that YouTube’s “restricted mode” (an opt-in setting that filters out “potentially objectionable content”) removes content with LGBT themes.

This isn’t the first time we’ve seen a social media giant be criticised for being a lax, morally irresponsible slacker and an evil, tyrannical censor and in the same week. Last month, Facebook were criticised for both failing to remove a group called “hot xxxx schoolgirls” and for removing a nude oil painting by an acclaimed artist.

That is not to say these things are equivalent. Quite obviously child abuse imagery is more troubling than a nude oil painting, and videos entitled “Jewish People Admit Organising White Genocide” are endlessly more problematic than those called “GAY flag and me petting my cat” (a highly important piece of content). I am not trying to claim that ~everything is relative~ and ~everyone deserves a voice~. Content that breaks the law must be removed and LGBT content must not. Yet these conflicting stories highlight the same underlying problem: it is a very bad idea to trust a large multibillion pound company to be the arbiter of what is or isn’t acceptable.

This isn’t because YouTube have some strange agenda where it can’t get enough of extremists and hate the LGBT community. In reality, the company’s “restricted mode” also affects Paul Joseph Watson, a controversial YouTuber whose pro-Trump conspiracy theory content includes videos titled “Islam is NOT a Religion of Peace” and “A Vote For Hillary is a Vote For World War 3”, as well as an interview entitled “Chuck Johnson: Muslim Migrants Will Cause Collapse of Europe”. The issue is that if YouTube did have this agenda, it would have complete control over what it wanted the world to see – and not only are we are willingly handing them this power, we are begging them to use it.

Moral panics are the most common justification for extreme censorship and surveillance methods. “Catching terrorists” and “stopping child abusers” are two of the greatest arguments for the dystopian surveillance measures in Theresa May’s Investigatory Powers Act and Digital Economy Bill. Yet in reality, last month the FBI let a child pornographer go free because they didn’t want to tell a court the surveillance methods they used to catch him. This begs the question: what is the surveillance really for? The same is true of censorship. When we insist that YouTube stop this and that, we are asking it to take complete control – why do we trust that this will reflect our own moral sensibilities? Why do we think it won't use this for its own benefit?

Obviously extremist content needs to be removed from YouTube, but why should YouTube be the one to do it? If a book publisher released A Very Racist Book For Racists, we wouldn’t trust them to pull it off the shelves themselves. We have laws (such as the Racial and Religious Hatred Act) that ban hate speech, and we have law enforcement bodies to impose them. On the whole, we don’t trust giant commercial companies to rule over what it is and isn’t acceptable to say, because oh, hello, yes, dystopia.

In the past, public speech was made up of hundreds of book publishers, TV stations, film-makers, and pamphleteers, and no one person or company had the power to censor everything. A book that didn’t fly at one publisher could go to another, and a documentary that the BBC didn’t like could find a home on Channel 4. Why are we happy for essentially two companies – Facebook and Google – to take this power? Why are we demanding that they use it? Why are we giving them justification to use it more, and more, and more?

In response to last week’s criticism about extremist videos on the YouTube, Google UK managing director Ronan Harris said that in 2016 Google removed nearly 2 billion ads, banned over 100,000 publishers, and prevented ads from showing on over 300 million YouTube videos. We are supposed to consider this a good thing. Why? We don't know what these adverts were for. We don't know if they were actually offensive. We don't know why they were banned. 

As it happens, YouTube has responded well to the criticism. In a statement yesterday, Google's EMEA President, Matt Brittin, apologised to advertisers and promised improvements, and in a blog this morning, Google said it is already "ramping up changes". A YouTube spokesperson also tweeted that the platform is "looking into" concerns about LGBT content being restricted. But people want more. The Guardian reported that Brittin declined three times to answer whether Google would go beyond allowing users to flag offensive material. Setting aside Brexit, wouldn't you rather it was up to us as a collective to flag offensive content and come together to make these decisions? Why is it preferable that one company takes a job that was previously trusted to the government? 

Editor’s Note, 22 March: This article has been updated to clarify Paul Joseph Watson’s YouTube content.

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