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Look at this amazing picture of Jupiter's moon Europa

This colourised picture of Europa is just beautiful.

It's called "Reddish Bands on Europa". Sunlight is coming in from the right; the blueish-green sections are water ice, while the red bands that look like a river and its tributaries is ice containing salts of sulfuric acid and magnesium sulfate. The bands do not flow, despite appearances - they are all part of Europa's frozen outer shell, mostly pure, which has cracked and shifted to expose the darker layer beneath.

It's centred on 2.9 degrees south latitude and 234.1 degrees west longitude, which (assuming Nasa is just stating the longitude strangely, as usually you only go up to 180 degrees) on Earth would be roughly where the Indonesian island of Siau is located. It covers a square roughly 163 by 167 kilometres, or about twice the land area of Manhattan.

This picture was not taken recently. Galileo - a Nasa probe which studied the Jovian system from 1995 to 2003, the first probe to do so - took the picture above in December of 1997 during a flyby of Europa. This is a colourised version, released this week by Nasa (you can see the original monochrome version here, covering an area almost twice as big), and the colour gives us a striking hint at what might be beneath the surface of the moon. In Nasa's words:

The reddish material is associated with the broad band in the center of the image, as well as some of the narrower bands, ridges, and disrupted chaos-type features. It is possible that these surface features may have communicated with a global subsurface ocean layer during or after their formation.

Europa is likely the place where we find extraterrestrial life within the Solar System, if we find it at all. Radiation from Jupiter powers plate tectonics which, in turn, leads to volcanism which, in turn, means a steady recycling of minerals and heat throughout the vast ocean that covers it. Deep sea vents there, as on Earth, might be home to simple bacteria-like organisms. Most of what we know about Europa came from Galileo, and it's remarkable that we gathered so much information that we're still digging through it today for further clues about what conditions there are like.

And yet. Look at that image. It has the strange shimmer of a still from a VHS tape, and the look of clay under a microscope. It is undoubtedly an alien world, made more alien through the artefacts of colourisation and the passage of time. And it is gorgeous, isn't it?

The European Space Agency will be launching Juice (the Jupiter Icy Moon Explorer) in 2022, another probe that will fly past Europa (and Ganymede, and Callisto) for further study; Nasa may launch a robotic lander aimed at Europa around the same time.

Ian Steadman is a staff science and technology writer at the New Statesman. He is on Twitter as @iansteadman.

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.