Guns galore

OPINION LETTERS State threat From Stephen Corry, Survival International Jared Diamond thinks that “traditional” societies sometimes do nasty things, and that state governments are a requisite for peace (12 January, p 26). His key point is that such societies kill many, be it in “war”, infanticide, or the abandonment or murder of the very old. It is of course true that many of the tribes he writes about are violent in various ways, but nobody would deny that people kill other people everywhere. Diamond claims that tribes are considerably more prone to killing than are societies ruled by state governments. But contrasting tribal societies with industrialised ones has always been more about politics than science, and we should be extremely wary of doing this. By saying a central government is the best answer, he is in effect attacking decades of work by tribal peoples and their supporters, who have opposed the theft of their land and resources, and asserted their right to live as they choose – often successfully.

The principal cause of the destruction of tribal peoples is the imposition of nation states. This does not save them; it kills them. London, UK

Looks familiar From Andrew Lockley Joe Kloc misses a possible explanation for the uncanny valley – the feeling of unease when seeing a robot with a strong human likeness (12 January, p 35). Perhaps because early humans could not easily breed with other hominins, this would have caused an evolutionary pressure to shun those we saw as almost human. Human-like robots may simply fall foul of this instinct. Milton Keynes, UK

Guns galore From Roger Taylor It will be interesting to see what the Centers for Disease Control and Prevention can come up with in its research into gun violence in the US (26 January, p 6), but I doubt it will provide any solace to those who think that gun control

Enigma Number 1735

A pile of coloured cubes IAN KAY I have several boxes, each containing a number of cubes. Each cube has black and white faces (at least one of each colour per cube), and each box contains all possible different cubes, with no duplicates. My three nephews opened the first box and each tried to assemble their own

2x2x2 cube with only one colour on its outer faces, and of course they failed. They then opened further boxes until they were each able to assemble a single-coloured 2x2x2 cube. They then put all the leftover cubes from the open boxes in a pile. How many cubes were there in the leftover pile?

WIN £15 will be awarded to the sender of the first correct answer opened on Wednesday 6 March. The Editor’s decision is final. Please send entries to Enigma 1735, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, or to [email protected] (please include your postal address). Answer to 1729 Xmas gifts: A, N, S, W, E and R are 17, 4, 3, 26, 5 and 9 The winner Christopher R. Jeggo of Woking, Surrey, UK

32 | NewScientist | 9 February 2013

epitome of the British scientific institution is under threat. We cannot sit back and wait for a rich benefactor to come along and save the day – we need to mobilise a national campaign to raise the necessary funds now. Guildford, Surrey, UK

Cooler climate laws hold the answer to reducing the violence. Apart from the deep resolve of America’s gun owners, sheer numbers are a problem – hundreds of companies have produced tens of thousands of guns every year for decades, and no one knows where most of them are. Even in the UK, over 90 years of rigorously enforced and very strict gun laws have failed to stop mass killings and a relentless increase in gun crime. That said, a clear-sighted look at the matter can only be a good thing. Meols, Merseyside, UK

Scientific SOS From Jim Al-Khalili, professor of physics, University of Surrey I would like to add my voice to Nobel laureate Harry Kroto’s rallying call to ensure the survival of the UK’s Royal Institution (26 January, p 27). Many of us in the science community are well aware of the financial pressures it has been under, which are more than simply a reflection of the current economic climate. But no one anticipated that its base, the wonderful building on Albemarle Street, London, might need to be sold off. I have been privileged to give many lectures in its famous theatre. It is truly one of the most inspirational places in the world to speak in. It seems crazy that at a time when science and science communication is riding a wave of popularity not seen for generations, we hear that the very

From Nicholas Lewis Several fair points are made in your assessment of the leaked draft of the Intergovernmental Panel on Climate Change’s (IPCC) Fifth Assessment Report (22/29 December 2012, p 8). However, saying that we now have a gloomier picture of the extent to which human-made aerosols reduce global warming is wrong. The draft says the cooling effect of aerosols is 40 per cent less than thought in 2007. This implies that the climate is less sensitive to carbon dioxide than we thought, and will warm less than feared as the amount of this gas in the atmosphere rises. On this basis, I calculate a doubling of CO2 compared to preindustrial levels can be expected to cause the mean global surface temperature ultimately to rise by 1.5 to 2°C (see details at webcitation.org/6DNLRIeJH) rather than the 3°C thought most likely by the IPCC in 2007. While this does not mean a continuing unchecked rise in CO2 is safe, the news is good, rather than gloomy. Bath, Somerset, UK

Feel the buzz? From Ted Lovesey A buzzing steering wheel to guide dazzled drivers is unlikely to work (19 January, p 20). Several years ago, the US military tried a similar device in a pilot’s helmet to alert them to danger, but with no success. When a person is stressed, as a dazzled driver is, they will concentrate on their main sensory