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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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Beesic Instinct: Labour wants to protect the bees from Brexit

Leaving the EU could weaken protections, which is a shame because politicans have a lot to learn from hive behaviour

No more bumbling around from Labour: the Party is now firmly pro-Bee. Their new manifesto says they would ban the controversial pesticides, known as neonicotinoids or “neonics”, from the UK:

The pledge is not just great news for bees, whose nervous systems are attacked by the chemicals, but for admirers of bees' elegant political decision making too. In fact, if our politics was more bee-like perhaps it would bug us less.

Bees, it turns out, are skilled in the political arts. When honey bees have to move to a new hive they send “scouts" to check out the options - a cosy crevice in your shed perhaps. The scouts then relay their findings to their comrades with a “waggle dance” up the honeycomb walls. Their sequence of steps indicates a site’s location, and if their opinion of your shed is not so hot, they’ll only bother to repeat their dance a couple of times. If they love it, they can dance a few hundred.

The longer a bee dances, the larger her audience grows. Her fellow scout bees can then follow the directions and visit the venue themselves. On their return, they perform their opinion for others. Eventually a hive should end up with a critical mass of the creatures all dancing for the same place. At that point, the entire hive takes flight to its new, democratically elected, home. Talk about waxing lyrical. 

Now just think about what such a system could do for British politics? Leaving aside the joyful prospect of our Right-Honourables jigging their way through parliament, would bees be vague about what kind of EU relationship they were choosing? No way. Would they have been swayed by dodgy facts? Nope. 

But, wait, what’s that I hear you say? – it’s not real democracy if only the scout bees get a vote! Fair point. But in that respect, neither is our own: just take 16 year-olds or foreign nationals. 

Plus the sad truth is that leaving the EU is putting the UK's capacity for strong, scientific decision making in doubt - not least over which pesticides are safe to use.

At present, The European Food Saftey Authority evaluates the safety of the substances proposed in new “plant protection products” and shares the results among the member states. In 2013, its findings led the European Commission to restrict the use of three key neonictides which the EFSA warned posed a “high acute risk” to honey bee health. This science has recently been reviewed by the EFSA and may see the restrictions extended to a complete ban

In the event of Brexit, the UK will have to decide on whether or not to maintain, extend or reduce EU rulings on pesticides. Labour's call for prohbiition is in line with calls from seventeen of the UK’s leading environment and conservation groups (the Green Party already pledged to ban neonoictinoids in their 2015 campaign). But while the Conservative government says it will take a "risk based" approach to the matter, it is under pressure from pesticide and farming groups to relax present regulation. In 2013 it also voted against the EU’s partial ban.

The even wider question, however, is how Britain will conduct scientific reviews and licensing in future. Dave Timms, senior policy campaigner for Friends of the Earth, is concerned about what our future relationship to the EFSA's review process will be: "You've got so many chemicals coming up for review all the time that member states take it in turn to be rapporteurs - and that process of sharing the science, sharing the effort, could be lost if we leave."

Even Defra has highlighted the problem of repatriating such decisions to the UK: "some areas (such as chemicals or ozone-depleting substances) might present more challenges than others because they are currently delivered by EU agencies, systems or resources,” it said in evidence presented for a recent government report.

The need for decisions based on shared and transparent scientific evidence has thus arguably never been greater. Otherwise we risk a situation in which, as Dr Elli Leadbeater of Royal Holloway told the NS, “evolution seems to have found a better solution than we have.”

India Bourke is an environment writer and editorial assistant at the New Statesman.

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