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Michael Marshall reports that a team from the China University of Geosciences in Beijing has found evidence of the 11-year solar sunspot cycle in Precambrian sedimentary rocks of south China ( 18 August, p 6 ). More than 50 years ago, Roger Anderson observed not only the 11-year cycle, but also resonances at 5.5 and …

Michael Brooks introduces us to the search for a particle that combines an axion and a flavon – an axiflavon – or a combination of this plus a Higgs, or some more convoluted combination ( 18 August, p 28 ). This reminded me of reading in Â鶹´«Ã½ in the mid-1960s of the search for …

Chris Baraniuk reports on nuclear power innovations such as floating reactors and shortening the half-life of nuclear waste ( 1 September, p 32 ). Perhaps tackling the energy crisis needs something more ambitious. Just after the second world war, liquid fluoride thorium reactors (LFTRs) and other molten salt reactors were developed as an alternative to …

You say that about 1 gram of carbon dioxide is emitted as a result of mining the uranium to generate 1 kilowatt-hour of energy in a nuclear power station . What about emissions during its construction, including making the concrete and steel, and from the large number of vehicle movements? I would expect another peak …

As someone who has conducted and published research into farmed salmon for more than 30 years, I take exception to the statement that it has just now been confirmed that triploid Atlantic salmon are effectively sterile ( 18 August, p 7 ). This brushes aside decades of research and dozens of publications in peer-reviewed journals …

Chris Baraniuk asks whether stupidity could save us from an AI apocalypse ( 1 September, p 13 ). Stupidity has not saved us from an environmental apocalypse – and most likely will not do so. Why should AI be any different? Even if we date environmental awareness only back to Rachel Carson's 1962 book Silent …

Joshua Howgego writes that the money in commercial bank accounts, which makes up roughly 97 per cent of the money used in the economy, is either created by interest on loans made by that institution, or by you when you make a deposit ( 25 August, p 36 ). Perhaps surprisingly, this is wrong. As …

Howgego discusses the risks of a cashless society . Another very significant aspect is a possible discriminatory effect. There seems to be a convenient assumption by both governments and commercial players that everyone is capable of using electronic devices and can understand what assets they have in remote ledgers. This ignores ageing, intellectual or physical …

You report that people paired with mean, negative robots performed a task faster and better than those working alongside kind, positive ones ( 25 August, p 16 ). There is at least one other interpretation. I used to get tasks done more efficiently when around negative colleagues because I would be in their presence for …

John Sherlock doubts the capacity of the Totten glacier in Antarctica to raise sea levels by more than 3 metres and you respond that its catchment area is more than 500,000 square kilometres (Letters, 1 September ). But the world's oceans cover 350 million square kilometres. I calculate that unless the average thickness of this …