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Jen Gunter's comment on the reluctance to market menstrual products using that word is sensible, helpful and represents the world I want to live in. But I am in the US, where half the people believe that anything that appeals to liberals is wrong, unacceptable, literally taking dictation from the devil and to be fought …

In believing that humans will still exist in billions of years, several readers attribute differing degrees of faith in our mental agility to see us through the death of the sun. However, big-brained Homo sapiens has been around for less than a million years, whereas jellyfish have chalked up over 500 million with no brain …

Assuming humans survive into the far future and continue to develop technologically, I reckon we will be able to construct and maintain a system of shields situated at a stable point between Earth and the sun that would reduce solar radiation reaching us and enable an ideal temperature, buying us at least some time before …

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 ).

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 …