Letters archive

Martin Watson and Tim Johnson worry about a possible black hole orbiting the sun colliding with it or another, similar black hole Letters, 24 April . In order for it to hit the sun, the very large angular momentum that the black hole would have as it orbits would need to be brought close to …

An ultra white paint has been invented and suggested as a means of cooling houses as potently as air conditioning 24 April, p 19 . However, perhaps it could also be used to provide a supply of fresh water. A horizontal, slightly conical metal sheet that was painted white on top would cool and condense …

Claiming that there was once a time when nature was in a perfect, "pristine pre-industrial state", as mentioned in Graham Lawton's column on ecocide, is a fallacy 8 May, p 24 . A preference for one environment or species over another is purely a human judgement; evolution has no inclination for, say, an English bluebell …

You report a study claiming that decreased physical activity during the first covid-19 lockdown in England may lead to increased obesity 8 May, p 10 . But I have recently read several convincing articles in New Scientist showing evidence that there is little correlation between exercise and weight change when measuring over periods longer than …

You report rising interest in the archaeology of seabeds that were once land 17 April, p 44 . Another reason to think coastal areas would be rich in possible finds is the idea that food supplies were effectively static in these areas. Unlike forests or open plains, where hunter-gatherers would have had to be constantly …

Regarding Brian Reffin Smith's letter reducing to absurdity the equation cited by Carlo Rovelli in his take on quantum theory Letters, 10 April . The equation doesn't deserve ridicule. It is no more controversial than the theory it is part of. Physicists used and accepted such "non-commuting" equations long before Rovelli was born.

In your look at the platypus, you write that its "pelt glows in UV light, which makes no sense for a nocturnal animal" 8 May, p 41 . It only makes no sense if you assume the fluorescence is the function, not just a consequence of a complex chemical structure for some other purpose, perhaps …

Nearly 60 years ago, I had an argument with the curate taking our bible class 1 May, p 39 . I thought the grove of silver birches outside might be conscious and able to communicate with each other; he wouldn't have a bit of it because, he told me, the bible said only humans could …

To add to James Wong's thoughts about the colour of watermelons historically, there is more evidence from the 14th century that the inside of the fruit was red then 24 April, p 22 . Moroccan scholar Ibn Battuta travelled throughout Eurasia. He loved his food and observed that Khwarazm, south of the Aral Sea, produced …

Thank you for your article about the fight to eradicate malaria 1 May, p 44 . Quite apart from reporting the success in tackling that terrible disease, you included a statistic that at any time would be a source of hope, and especially now. Anuradha Gupta's quote saying that, compared with two decades ago, we …