Letters archive

Adam Vaughan explores plans for genetic testing by England's National Health Service ( 20 July, p 12 ). Such testing has the potential to offer significant benefits to individuals and to society. But it is misguided and even dangerous to talk of anonymised data in this context. There is much discussion about how easy it …

Chanda Prescod-Weinstein is correct to highlight the global helium supply crisis ( 13 July, p 22 ). We should worry enormously about the paucity of helium reserves, with production for export as aby-product of natural gas limited to the US, Qatar and Algeria. Each of these has its own quirks that could limit helium production. …

Graham Lawton helps perpetuate a common climate denier myth by saying that in the 1970s scientists were worried that we were about to plunge into another full-blown icy spell ( 6 July, p 38 ). But a literature review finds that, even then, global warming dominated scientists' thinking as one of the most important forces …

You say that the human brain is the most complex object in the known universe (Leader, 22 June ). But it is part of the human body, which is an object, and so must be the most complex. But humans are parts of societies, which could be called "objects", and...

Chanda Prescod-Weinstein's lovely article on the origins and scarcity of terrestrial helium reminds me of a tour I had, about five years ago, around the chemistry lab of a leading UK university ( 13 July, p 22 ). It had very impressive, high-performance nuclear magnetic resonance machines. We asked our guide whether the liquid helium …

Daniel Cossins says the search for answers to the mysteries of time "takes us into the strange borderlands between neuroscience and physics" ( 6 July, p 32 ). He should include philosophy in that map. The philosopher Peter Geach argued in Mental Acts for the necessity of philosophy in such cases, saying that no experiment …

When a ball bounces, it converts kinetic energy to heat energy by deformation, so each bounce is lower than the one before. The laws of physics are generally reversible in time, but, as Cossins discusses , those involving heat, or thermodynamics, are not. Heat is an "emergent" thing: a phenomenon that appears only when we …

You report Andrew Campbell and his colleagues developing a system for employers to snoop on staff, including when they were at their desk and details about their sleep, heart rate and stress levels ( 6 July, p 9 ). Their algorithm – with an accuracy characterised as "still quite low" – classifies employees as "higher" …

Given all that SpaceX has done to open up the space frontier by reducing costs and developing reusable rockets, I was surprised to read that the best that could be said about SpaceX were comments about its chief executive's use of the word "colonising" ( 13 July, p 42 ). If more rockets were reused, …

You urge that we return to the moon "for all the right reasons" and say lunar bases will become staging posts for exploring Mars and the rest of the solar system (Leader, 13 July ). The "right reasons" probably won't be a priority unless we first tackle the problem of our ancient hunter-gatherer brains. Humanity …