Where does the moon come from?

Whether we’re trying to find out where it came from, or how to siphon off some of its energy, grappling with the moon is harder than it looks.

When the Apollo astronauts brought back pieces of lunar rock, the samples promised to answer the question of the moon’s origin. It’s a question we are still asking.

The “big splash” theory of a gargantuan collision between two planets is the favourite. The idea is that a Mars-sized object hit the young earth, throwing off a load of matter which coalesced to form the moon.

Scientists became convinced that the big splash theory must be correct because it calls for the stuff in the moon to be lighter than the atoms making up earth. Initial analysis of the relative abundance of various forms of atoms (known as isotopes) in the Apollo samples provided supporting evidence.

However, researchers then thought to take account of the effects of a few billion years of bombardment by high-energy subatomic particles called cosmic rays. Because earth is protected from cosmic rays by its magnetic field, these would change the moon’s isotope abundances only and in particular ways. Unfortunately, all this has been a dampener on the big splash theory.

Other theories are available. The moon could simply have formed independently at the same time as the earth, for instance. Or it could have been a passing body that fell into our planet’s gravitational field and got trapped.

Most planetary scientists remain convinced that the big splash is right but to convince themselves and others they have to work out a consistent story. That’s why they gathered to sift through all the evidence at the Royal Society in London on 23 and 24 September.

Despite the lack of consensus, scientific achievements in this area are astonishing. We are narrowing down the timings of events that occurred 4.5 billion years ago. Some of the research that was presented showed that the moon is roughly 100 million years younger than we had thought. This kind of forensic analysis of vaporised rock is an extraordinary feat.

If only our progress in harvesting lunar energy was as extraordinary. Most experts are convinced that there is a way to profit from the moon’s gravitational pull on the oceans, but the devil is in the detail.

The Scottish government recently gave the go-ahead for the Pentland Firth to host Europe’s largest tidal energy project. It is estimated that the Pentland Firth could eventually meet half of Scotland’s electricity needs, but for now engineers are aiming to have 40 per cent of homes in the Scottish Highlands running off lunar power by 2020.

In many ways, it’s a great leap forward. Yet meeting 40 per cent of the needs of one of the UK’s less inhabited regions also seems a little underwhelming. One of the benefits of being a small island is that Britain has copious tidal and wave power at its disposal: enough to meet a fifth of our electricity needs.

Whether we’re trying to find out where it came from, or how to siphon off some of its energy, grappling with the moon is harder than it looks.

A 'Super Moon' rises over Sydney. Image: Getty

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 07 October 2013 issue of the New Statesman, The last days of Nelson Mandela

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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.