High voltage: Hinkley power stations near Bristol. Photo: Getty
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Path of least resistance: the quest for room-temperature superconductors

Michael Brooks’s Science Column. 

We don’t talk enough about superconductors. These materials carry electricity without losing energy and could change the world – if only we could rediscover the kind of progress we used to make in this field.

We have known about superconductors since 1911, when the first one was discovered. In normal conductors – an aluminium wire at room temperature, for instance – electrons move through the material, jostled by all the other particles. Cool that aluminium down to -272° Celsius, though, and it becomes a superconductor. The electrons encounter no resistance, zipping along the wire as if they were the only particles in town.

That is significant: the copper cables used to transmit electricity from power stations to your home lose 10 per cent of energy through electrical resistance. If those cables were made of a superconductor, no energy would be lost. We would not need to generate so much power, reducing our dependence on fossil fuels.

Even better would be the ability to store energy. Renewable sources such as wind, wave and solar power generate energy at times and rates beyond our control. That power could be stored indefinitely in superconducting circuits. Because these don’t dissipate any of the energy, a superconducting power store is a battery whose charge lasts as long as you need it to.

There are also transport applications. Superconductors repel magnets and engineers have exploited this by putting superconductors on trains and electromagnets on the track. The repulsion levitates the train above the track, hugely reducing friction and clearing the way for ultra-fast transport.

So far, though, magnetic levitation trains have taken off in only a couple of places around the world. That is because superconductors are still not super enough. The main problem is that more energy is spent to cool materials until they become superconducting than is saved through reduced transmission loss, better energy storage capacity or greater transport efficiency.

This is a tale of dashed hopes. From 1911 to the 1980s, superconductors were available at temperatures below -240° Celsius only. We thought we had beaten this barrier in 1986 when we discovered a copper compound that was superconducting at -183° Celsius. Suddenly, things were looking up: we could turn materials superconducting by cooling them with liquid nitrogen, a relatively cheap and easy means of refrigeration.

However, it still wasn’t cheap and easy enough to make superconducting technology mainstream. So we cooked up more of these “high-temperature superconductors”. By 1993, we had got to about -140° Celsius. Things were looking very good indeed. And then, almost nothing. We are still less than halfway to room-temperature superconductors.

That’s because, despite decades of research, we’re still trying to figure out how they work. Progress is painfully slow. In October, French and US researchers finally confirmed a prediction, made in 1964, about one microscopic characteristic of what is going on inside superconductors.

This latest breakthrough might lead to superconductors that can withstand higher magnetic fields and thus give hospitals better MRI scanners – but it won’t push that critical transition point up towards room temperature. We can only hope that will be achieved by the researchers investigating other features of superconduction. No one thinks such a breakthrough is imminent. In an age when we have come to understand some of the deepest secrets of the universe, the secrets of the superconductor are keeping our feet firmly on the ground. 

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 13 November 2014 issue of the New Statesman, Nigel Farage: The Arsonist

Davide Restivo at Wikimedia Commons
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Scientists have finally said it: alcohol causes cancer

Enough of "linked" and "attributable": a new paper concludes that alcohol directly causes seven types of cancer.

I don't blame you if you switch off completely at the words "causes cancer". If you pay attention to certain publications, everything from sunbeds, to fish, to not getting enough sun, can all cause cancer. But this time, it's worth listening.

The journal Addiction has published a paper that makes a simple, yet startling, claim: 

"Evidence can support the judgement that alcohol causes cancer of the oropharynx [part of the throat], larynx, oesophagus, liver, colon, rectum and [female] breast"

So what's especially significant about this? 

First, scientists, unlike journalists, are very wary of the word "causes". It's hard to ever prove that one action directly led to another, rather than that both happened to occur within the same scenario. And yet Jennie Connor, author of the paper and professor in the Preventive and Social Medicine department at the University of Otago, New Zealand, has taken the leap.

Second, alcohol not only causes cancer of one kind – the evidence supports the claim that it causes cancer at seven different sites in our bodies. There was weaker evidence that it may also cause skin, prostate and pancreatic cancer, while the link between mouth cancers and alcohol consumption was the strongest. 

What did we know about alcohol and cancer before?

Many, many studies have "linked" cancer to alcohol, or argued that some cases may be "attributable" to alcohol consumption. 

This paper loooks back over a decade's worth of research into alcohol and cancer, and Connor concludes that all this evidence, taken together, proves that alcohol "increases the incidence of [cancer] in the population".

However, as Connor notes in her paper, "alcohol’s causal role is perceived to be more complex than tobacco's", partly because we still don't know exactly how alcohol causes cancer at these sites. Yet she argues that the evidence alone is enough to prove the cause, even if we don't know exactly how the "biologial mechanisms" work. 

Does this mean that drinking = cancer, then?

No. A causal link doesn't mean one thing always leads to the other. Also, cancer in these seven sites was shown to have what's called a "dose-response" relationship, which means the more you drink, the more you increase your chances of cancer.

On the bright side, scientists have also found that if you stop drinking altogether, you can reduce your chances back down again.

Are moderate drinkers off the hook?

Nope. Rather devastatingly, Connor notes that moderate drinkers bear a "considerable" portion of the cancer risk, and that targeting only heavy drinkers with alcohol risk reduction campaigns would have "limited" impact. 

What does this mean for public health? 

This is the tricky bit. In the paper, Connor points out that, given what we know about lung cancer and tobacco, the general advice is simply not to smoke. Now, a strong link proven over years of research may suggest the same about drinking, an activity society views as a bit risky but generally harmless.

Yet in 2012, it's estimated that alcohol-attributable cancers killed half a million people, which made up 5.8 per cent of cancer deaths worldwide. As we better understand the links between the two, it's possible that this proportion may turn out to be a lot higher. 

As she was doing the research, Connor commented:

"We've grown up with thinking cancer is very mysterious, we don't know what causes it and it's frightening, so to think that something as ordinary as drinking is associated with cancer I think is quite difficult."

What do we do now?

Drink less. The one semi-silver lining in the study is that the quantity of alcohol you consume has a real bearing on your risk of developing these cancers. 

On a wider scale, it looks like we need to recalibrate society's perspective on drinking. Drug campaigners have long pointed out that alcohol, while legal, is one of the most toxic and harmful drugs available  an argument that this study will bolster.

In January, England's chief medical officer Sally Davies introduced some of the strictest guidelines on alcohol consumption in the world, and later shocked a parliamentary hearing by saying that drinking could cause breast cancer.

"I would like people to take their choice knowing the issues," she told the hearing, "And do as I do when I reach for my glass of wine and think... do I want to raise my risk of breast cancer?"

Now, it's beginning to look like she was ahead of the curve. 

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