Comet 67P/Churyumov-Gerasimenko is seen in a photo taken by the Rosetta spacecraft, 6 August. Photo: Getty
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Hunting the rocky rubber duck: how comet-chasing Rosetta could change history

This ball of rock and ice formed at the same time as our solar system and should, if predictions are correct, contain complex organic molecules, the same stuff as terrestrial life is made from.

We learn a lot about ourselves from the newspapers. When the Times reported the launch of the comet-hunting Rosetta spacecraft in March 2004, the story merited only 44 words. The report was consigned to page eight; the front page was dominated by the Ashura massacre in Iraq, in which al-Qaeda bombers killed 178 Shia Muslims.

Ten years later, after Rosetta finally reached comet 67P/Churyumov-Gerasimenko, the Times put the spacecraft on page 19, behind stories of wrangles over monkey-selfies, among other things. But don’t be fooled: Rosetta is important. In an era of fatalistic acceptance of humanity’s shortcomings, the Rosetta team reminds us what we can achieve.

The comet, which is about 400 million kilometres from earth, appears to be composed of two lumps of rock, one smaller than the other, so that it resembles a rocky rubber duck. To put its spacecraft into orbit around this oddity, with an eventual view to sending an instrument-laden craft to the surface in a controlled landing, the European Space Agency has had to harness unprecedented creativity.

The solution is this: initially, Rosetta will orbit the comet in a triangular pattern as it maps the exact shape and density of the rock. For two weeks, Rosetta will be at 100km from its surface, then at 70km – at which point the flying will get more difficult. The comet occasionally ejects plumes of gas from its core, and these will buffet the spacecraft, potentially knocking it off course. Early next month, if all has gone well, Rosetta will drop into a circular orbit 30km from the comet’s surface. After another fortnight, it will move further in, sitting at a precarious distance of 10km. Then, in November, the lander will drop to the surface and the team will have made history.

The mission’s aim is to discover what exactly the comet is made of. This ball of rock and ice formed at the same time as our solar system and should, if predictions are correct, contain complex organic molecules, the same stuff as terrestrial life is made from. Rosetta’s lander is equipped with instruments that will help us determine whether life on earth was seeded by a comet crashing into our planet. As history lessons go, it doesn’t get more profound than this.

Such is the promise of the mission that the researchers have described comet 67P/Churyumov-Gerasimenko as “scientific Disneyland”. There will certainly be a roller-coaster ride as the comet moves towards the sun: some of its ice core will be vaporised, throwing out pieces of rock and jets of steam, making its environment hard to endure.

But endure Rosetta no doubt will. The problem-solving demonstrated by the research team showcases what scientists can achieve when they collaborate internationally. Two thousand people, from 14 European countries and the US, are creating milestones in, and lessons about, human history. So it’s a shame that humanity’s worst side seems to eclipse Rosetta’s every move.

The lander will touch down on the comet’s surface – our first controlled landing on a comet – on 11 November. That will be Armistice Day, in the centenary year of the outbreak of the First World War. Most media reports will no doubt squander the chance to celebrate humanity’s greater achievements, preferring that we wring our hands about history and yet fail to learn its lessons. Don’t be distracted: there will be more insight to gain from Rosetta’s moment of glory. 

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 August 2014 issue of the New Statesman, A century of meddling in the Middle East

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.