Curiosity taking a self-portrait. Image: Nasa
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Curiosity sniffs farts on Mars, could mean extinction of humanity

Fluctuations in methane gas in the Martian atmosphere, detected by the Curiosity rover, could mean that there's life living below the surface of Gale Crater. The implications could be surprising.

There's life on Mars! Maybe. Again. What's going on?

Nasa has announced that the Curiosity rover has detected spikes in methane concentration in the atmosphere within the Gale Crater. Over the last 20 months Curiosity has sampled the chemical makeup of the air around it a dozen times, finding that normally there are seven methane molecules per ten billion other air molecules (which on Mars is about 96 per cent carbon dioxide) - except on two occasions, where it jumped to ten times that. That's a big deal because methane doesn't just linger around; it's produced by some chemical process and then dissipates relatively quickly, so whatever's producing it must be doing it recurrently and frequently.

We all have experience with methane production (particularly around the Christmas season, with brussel sprouts on the table), but it's important to stress this isn't a definitive proxy for Martian life. Sure, it could be microbes, but it could also come from the reaction of the mineral olivine with water, as this Nasa infographic shows, and that's been the suspicion ever since methane was first detected in the atmosphere by astronomers in 2009. But we've always known that Mars' methane is unevenly distributed, and possibly seasonal, and that there are a number of alternative sources for it than bacteria "burping".

The announcement also included the news that the rock sample that Curiosity drilled into in May 2013 yielded further organic molecules when analysed, and also revealed important data about the history of the planet's water - and when it was lost. What we can really say here is that we have even more evidence to support the conclusion that Mars was habitable and Earth-like (or at least from the perspective of microbial life) billions of years in the past, but also that we don't know yet if it still is today.

Something we have to think about when we find life somewhere else - and we will find aliens, eventually, in centuries if necessary - is what the means for us, humanity, in the big picture. Statistically. Those of us who gamble might well consider it a bad omen.

There's this idea that there's a "Great Filter" which none, or very little, life gets through, on the cosmological scale. It was first outlined by economist Robin Hanson in 1996, and others have since refined it or challenged it, but basic premise is this: we haven't met aliens yet because all intelligent life capable of star travel is killed off before it spreads beyond its home star.

We know now that the number of planets far outnumbers the number of stars in the universe, and that it's therefore probable that there are billions upon billions of planets capable of hosting life. And, if life is like us, and works out how to colonise other planets and stars, we know that the amount of time it should take to colonise a large part of, say, a galaxy, should be short compared to galactic timescales - that is, if there's a lifeform that can colonise another star, it's reasonable to assume that it'll colonise almost all the stars it can in pretty short order, at a rate of a few centuries perhaps. So, if there are lots of Earth-like planets with (presumably) Earth-like intelligence on them, where the hell is everybody? (This is the famous Fermi paradox.)

The explanation Hanson and others have suggested is that somewhere, between the emergence of single-cellular life and interstellar travel, there's the Great Filter - many planets reach it, but few get through, because of asteroid strikes or runaway climate change or resource depletion or... anything we have yet to experience as a species. We can't see anybody else, and the universe feels like an empty place, because the cumulative probability of making it through every step - a safe planet where RNA appears and then single-celled life and then multi-celled and then the evolution of a tool-using lifeform that then develops interstellar travel - is so low as to be zero.

What makes the possibility that life evolved independently on Mars (especially multi-cellular life) so worrying from this perspective, then, is that it means the first few stages of that process are even easier than we thought - and that means getting beyond the stage we're at now must be much, much harder than we thought. The probability works out to tell us that we're at the stage of biological and cultural and technological development where we're wiped out before we take the next step.

There are, though, a dozen or more retorts to this: maybe intelligent life is intelligent enough not to have to colonise everywhere, or maybe it's intelligent to the extent that it's able to choose to remain invisible to us. But it's still a sobering thought that the thrilling discovery of alien life could be one of the last great moments in our species before a statistically-likely mishap hits us from left field.

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

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Don’t shoot the messenger: are social media giants really “consciously failing” to tackle extremism?

MPs today accused social media companies of failing to combat terrorism, but just how accurate is this claim? 

Today’s home affairs committee report, which said that internet giants such as Twitter, Facebook, and YouTube are “consciously failing” to combat extremism, was criticised by terrorism experts almost immediately.

“Blaming Facebook, Google or Twitter for this phenomenon is quite simplistic, and I'd even say misleading,” Professor Peter Neumann, an expert on radicalisation from Kings College London, told the BBC.

“Social media companies are doing a lot more now than they used to - no doubt because of public pressure,” he went on. The report, however, labels the 14 million videos Google have removed in the last two years, and the 125,000 accounts Twitter has suspended in the last one, a “drop in the ocean”.

It didn’t take long for the sites involved to refute the claims, which follow a 12-month inquiry on radicalisation. A Facebook spokesperson said they deal “swiftly and robustly with reports of terrorism-related content”, whilst YouTube said they take their role in combating the spread of extremism “very seriously”. This time last week, Twitter announced that they’d suspended 235,000 accounts for promoting terrorism in the last six months, which is incidentally after the committee stopped counting in February.

When it comes to numbers, it’s difficult to determine what is and isn’t enough. There is no magical number of Terrorists On The Internet that experts can compare the number of deletions to. But it’s also important to judge the companies’ efforts within the realm of what is actually possible.

“The argument is that because Facebook and Twitter are very good at taking down copyright claims they should be better at tackling extremism,” says Jamie Bartlett, Director of the Centre for the Analysis of Social Media at Demos.

“But in those cases you are given a hashed file by the copyright holder and they say: ‘Find this file on your database and remove it please’. This is very different from extremism. You’re talking about complicated nuanced linguistic patterns each of which are usually unique, and are very hard for an algorithm to determine.”

Bartlett explains that a large team of people would have to work on building this algorithm by trawling through cases of extremist language, which, as Thangam Debonnaire learned this month, even humans can struggle to identify.  

“The problem is when you’re dealing with linguistic patterns even the best algorithms work at 70 per cent accuracy. You’d have so many false positives, and you’d end up needing to have another huge team of people that would be checking all of it. It’s such a much harder task than people think.”

Finding and deleting terrorist content is also only half of the battle. When it comes to videos and images, thousands of people could have downloaded them before they were deleted. During his research, Bartlett has also discovered that when one extremist account is deleted, another inevitably pops up in its place.

“Censorship is close to impossible,” he wrote in a Medium post in February. “I’ve been taking a look at how ISIL are using Twitter. I found one user name, @xcxcx162, who had no less than twenty-one versions of his name, all lined up and ready to use (@xcxcx1627; @xcxcx1628, @xcxcx1629, and so on).”

Beneath all this, there might be another, fundamental flaw in the report’s assumptions. Demos argue that there is no firm evidence that online material actually radicalises people, and that much of the material extremists view and share is often from mainstream news outlets.

But even if total censorship was possible, that doesn’t necessarily make it desirable. Bartlett argues that deleting extreme content would diminish our critical faculties, and that exposing people to it allows them to see for themselves that terrorists are “narcissistic, murderous, thuggish, irreligious brutes.” Complete censorship would also ruin social media for innocent people.

“All the big social media platforms operate on a very important principal, which is that they are not responsible for the content that is placed on their platforms,” he says. “It rests with the user because if they were legally responsible for everything that’s on their platform – and this is a legal ruling in the US – they would have to check every single thing before it was posted. Given that Facebook deals with billions of posts a day that would be the end of the entire social media infrastructure.

“That’s the kind of trade off we’d be talking about here. The benefits of those platforms are considerable and you’d be punishing a lot of innocent people.”

No one is denying that social media companies should do as much as they can to tackle terrorism. Bartlett thinks that platforms can do more to remove information under warrant or hand over data when the police require it, and making online policing 24/7 is an important development “because terrorists do not work 9 to 5”. At the end of the day, however, it’s important for the government to accept technological limitations.

“Censorship of the internet is only going to get harder and harder,” he says. “Our best hope is that people are critical and discerning and that is where I would like the effort to be.” 

Amelia Tait is a technology and digital culture writer at the New Statesman.