Letters archive

I noted that Alex Wilkins left the most important question to the final sentence of his piece on terraforming Mars: should we? Well, of course not. The urge to spread destructive humanity across the cosmos is merely the 21st-century equivalent of European explorers seeking to solve the problems of overexploited Europe by conquering new lands. …

Good to see the hype about screen time deflated and the question of a more sedentary childhood dealt with. A missing factor is restrictive parenting. When I was a child under 10 (early 1950s), I was totally free to roam the streets or the countryside with my friends. Nobody questioned it and you can't have …

Charles Joynson asks whether bringing back the dodo will put the bird on the menu. That isn't very likely, I guess. In 1974, Dutch author Jan Wolkers published his novel De Walgvogel . The title refers to the dodo, which Dutch sailors found on Mauritius and hunted for food. They found the flesh not very …

Modern palaeoanthropology and archaeology can be misleading, I would suggest, and classification of "post-primates" like us and "prehistoric man" is confused ( 3 August, p 32 ). As we devise post-primate species and genus from a scattering of bones and stones, we can't see speech or family structures and dynamics that may be more significant …

The universe is abnormal, in that measurements of most things don't fit a normal curve, where the mean (average) and the median (typical) are the same. So your editorial's claim that it is "unfair" that bigger countries win more medals is irrelevant. Perhaps a metric such as medals per million people would be better ( …

Scanning "The smarter way to a fitter you", I discovered a comprehensive account of most aspects of exercise. However, apart from home-based game playing and pedometer measures, there was no mention of domestic work ( 27 July, p 32 ). There seemed to be a theme of avoiding boredom in exercise pursuits, and maybe that …

Dave Johnson wonders if time can flow backwards in some small pockets of space, given increasing entropy equates with time's arrow. This shows how intuition fails with huge and tiny numbers. When two atoms bounce off each other elastically, their energies tend to be more equal afterwards (increased entropy). When, by chance, they are less …

When I read that the American Academy of Pediatrics was recommending weight-loss medication for children aged 12 and up, my moral stance on this initially made me cringe. However, after completing the article, I support this idea despite reading contradictory advice from the US Preventive Services Task Force, which cites insufficient evidence and suggests long-term …

As the article "Super AI is still sci-fi" noted, the term "artificial intelligence" is little more than a good branding exercise. This is much more attractive to investors than using facts about machine learning pattern recognition algorithms with more powerful graphics processing units. When it comes to "AI", there is nothing approaching "intelligence", so why …

A vaccine to stop cows burping methane is very ingenious. But wouldn't it be simpler to farm animals that eat grass and don't burp or fart much methane ? They are called kangaroos ( 10 August, p 16 ).