Hiding in plain sight

The Easter holiday rush is receding into distant memory. The only thing airport security personnel have to worry about is what happens when everyone starts arriving for the Olympics. That, and the helpful physicists who have worked out how to smuggle a gun through a metal detector.

It all started as a bit of harmless blue-sky thinking. In the late 1960s, a Russian physicist pointed out the fun you could have if you invented a material that bends light in the opposite direction to normal. You could use it as an invisibility cloak, he said: just as water diverts round a rock in a stream by going first to one side, then back to the other, light bent in two different directions as it passed an object would give a viewer the impression that the light had travelled in a straight line and that the object simply wasn’t there.

Oh, how everybody laughed. Then, in 2000, someone turned this ridiculous fantasy into reality. John Pendry of Imperial College London showed how to create “left-handed materials” that would bend microwave radiation the wrong way. The practicalities were a little cumbersome and it didn’t work with visible light. But still, it was surprising, impressive and fun, in a nerdy kind of way.

Over the past decade, the technology has matured. At first, left-handed materials were constructed from intricate arrays of copper rings and could only hide tiny objects from a microwave detector. Now, we have invisibility “carpets” made from cheap and widely available crystals of the mineral calcite. They are able to hide objects the size of your thumb – and they work in visible light.

That technology is not yet going to smuggle a gun through airport security, though. Even if the X-ray machine doesn’t make the outline obvious, the magnetic field from the steel triggers an alarm. But a paper recently published in the journal Science can get you round that obstacle.

As it turns out, you can cloak a metal’s magnetic field for less than £1,000. First, wrap your gun in a layer of superconducting tape. Magnetic fields cannot pass through a layer of superconductor, so the scanner wouldn’t see the gun’s field. The scanner would see the superconductor’s field, though. However, this can be countered by adding a layer of flexible magnetic strip, rather like that found on the back of a fridge magnet. The researchers showed that this combination of readily available materials does a reasonable job of cloaking a magnetic field.

Touching the void

OK, it’s still not quite a credible threat. The superconductor has to be kept at liquid-nitrogen temperatures and a cloud of nitrogen vapour coming out of your hand luggage might raise a few eyebrows. A simple thermal detector would certainly put paid to any gun-smuggling plans.

But the physicists aren’t beaten yet. While some have been content to bend light as it travels through space, Martin McCall of Imperial College London has played around with bending light as it travels though time.

The technique involves slowing down and speeding up light inside an optical fibre – something that physicists have learned to do with astonishing skill in the past few years. McCall now has a blueprint for a device that doesn’t just make things invisible; it makes it look like they never even happened. It only works on technologies with an optical fibre feed, such as a CCTV camera. Nevertheless, in principle, we now know how to create the illusion of a void in both space and time – a void that could plausibly be exploited to evade surveillance technologies. Of course, it’s ridiculous. But where these troublesome physicists are involved, nothing remains ridiculous for long.

Michael Brooks’s “Free Radicals: the Secret Anarchy of Science” is published by Profile Books (£12.99)

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 30 April 2012 issue of the New Statesman, The puppet master

DebateTech
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Politicians: it's no longer OK to know nothing about technology

It’s bad enough to joke about not being "techy"; it's worse to back a piece of legislation from a position of ignorance. 

Earlier this week, facing down a 600-strong battalion of London’s tech sector at a mayoral hustings in Stratford, Zac Goldsmith opened his five minute pitch with his characteristic charm. “I’m not very techy!” he exclaimed. “I understand coding about as well as Swahili!”

Pointless jibe at a foreign language aside, this was an ill-chosen way to begin his address - especially considering that the rest of his speech showed he was reasonably well-briefed on the problems facing the sector, and the solutions (including improving broadband speeds and devolving skills budgets) which could help.

But the offhand reference to his own ignorance, and the implication that it would be seen as attractive by this particular audience, implies that Goldsmith, and other politicians like him, haven’t moved on since the 90s. The comment seemed designed to say: “Oh, I don't know about that - I'll leave it to the geeks like you!"

This is bad enough from a mayoral hopeful.  But on the same day, the Intelligence and Security Committee of Parliament filed its report on the Draft Investigatory Powers Bill, the legislation drafted by the Home Office which will define how and how far the government and secret services can pry into our digital communications. Throughout, there's the sense that the ISC doesn't think the department behind the bill had a firm grasp on the issues at hand. Words like "inconsistent" and "lacking in clarity" pop up again and again. In one section, the authors note:

"While the issues under consideration are undoubtedly complex, we are nevertheless concerned that thus far the Government has missed the opportunity to provide the clarity and assurance which is badly needed."

The report joins criticism from other directions, including those raised by Internet Service Providers last year, that the bill's writers didn't appear to know much about digital communications at all, much less the issues surrounding encryption of personal messages.

One good example: the bill calls for the collection of "internet connection records", the digital equivalent of phone call records, which show the domains visited by internet users but not their content. But it turns out these records don't exist in this form: the bill actually invented both the phrase and the concept. As one provider commented at the time, anyone in favour of their collection "do not understand how the Internet works". 

Politicians have a long and colourful history of taking on topics - even ministerial posts - in fields they know little to nothing about. This, in itself, is a problem. But politicians themselves are often the people extolling importance of technology, especially to the British economy - which makes their own lack of knowledge particularly grating. No politician would feel comfortable admitting a lack of knowledge, on, say, economics. I can’t imagine Goldsmith guffawing "Oh, the deficit?  That's all Greek to me!"  over dinner with Cameron. 

The mayoral candidates on stage at the DebateTech hustings this week were eager to agree that tech is London’s fastest growing industry, but could do little more than bleat the words “tech hub” with fear in their eyes that someone might ask them what exactly that meant. (A notable exception was Green candidate Sian Berry, who has actually worked for a tech start-up.) It was telling that all were particularly keen on improving internet speeds -  probably because this is something they do have day-to-day engagement with. Just don't ask them how to go about doing it.

The existence of organisations like Tech London Advocates, the industry group which co-organised the hustings, is important, and can go some way towards educating the future mayor on the issues the industry faces. But the technology and information sectors have been responsible for 30 per cent of job growth in the capital since 2009 - we can't afford to have a mayor who blanches at the mention of code. 

If we’re to believe the politicians themselves, with all their talk of coding camps and skills incubators and teaching the elderly to email, we need a political sphere where boasting that you're not "techy" isn’t cool or funny - it’s just kind of embarrassing. 

Barbara Speed is a technology and digital culture writer at the New Statesman and a staff writer at CityMetric.