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In NASA's search for the biosignature of life on other worlds, could artificial intelligence help? When considering life's chemical origins, two relatively simple structures that appear to have self-replicating properties are prion proteins and types of RNA. For life to get going, these would need suitable substrates on which to develop. We might be guided …

Merlin Reader advises free public transport as one way to have fewer cars on the roads. I advocated that for years, but then learned that it has been implemented in some French towns, and the result wasn't less car use. The people who used the free transport were those who would normally walk or go …

As a menopausal woman of 54 and a mother, I was gratified to read your editorial on the unequal treatment of women's health issues. Last year, I – and the many hundreds of thousands of women who have had to struggle to get an appropriate treatment for this "natural" phase of our lives – was …

Joachim Moortgat at the Ohio State University contributed to work to identify natural hydrogen deposits via soil circles ( 3 February, p 32 ).

Like Clare Wilson, I too tried a blood glucose monitor from ZOE, partly out of curiosity and partly for potential health benefits. I wasn't too concerned about blood glucose "spikes". It was the resulting "dips" I wanted to eliminate. What I had surmised were that periods of low glucose, which felt like having a hangover, …

You report on the use of exercise for long covid. This condition and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) have some important clinical and pathological overlaps and a significant proportion of people with long covid also meet diagnostic criteria for ME/CFS ( 17 February, p 14 ). In new guidelines on ME/CFS in 2021, England's National …

Matthew Sparkes wonders why the ancient Greeks didn't go on to develop greater mechanical marvels than they did. I believe the answer may lie in the changing political forces of the time, as the dominance of the Mediterranean was changing from the science and knowledge-loving Greeks to the imperialist Romans. As far as the latter …

Terms like "emergent" and "complex" are often deployed as though they present a clear, simple explanation of mind and consciousness. In fact, we have no idea how, or if, mind arises from mindless material. Equally, to say consciousness is an emergent property of matter implies that this phenomenon is somehow already present in it. Consciousness …

It was interesting to read how learning to play the piano causes changes in different brain areas ( 3 February, p 12 ). Many other instruments produce their notes through different methods from far fewer basic keys or strings, such as varying lip pressures or pressing strings down at different points. Consequently, these are learned …

Your view on whether the world has already warmed by 1.5°C refers to extreme weather events. The resulting human tragedies are often referred to as "natural disasters" by politicians and the media. But the causes are becoming less and less natural. Let's start calling them what they are – "climate disasters" ( Leader, 10 February …