Letters archive

I read with interest Donna Lu's article on Rowan Zellers and his colleagues using a machine learning system that can generate fake news in order to detect it ( 15 June, p 15 ). Its reported accuracy is impressive, but I note that their Grover model has been tested only on a sample of fake …

Thomas Patrick Reid wonders whether an object's density fools our perception of its weight (Letters, 22 June ). I sometimes carry bags of cement and of hydrated lime, both with a mass of 25 kilograms. The lime is approximately half as dense, so its bags are twice as large. Against all knowledge to the contrary, …

Yes, density does affect our perception of weight . When I worked in concrete technology, I was told about a laboratory open day for which staff made small concrete cube specimens using different mixes. At one extreme, they replaced the coarse gravel aggregate with lead shot and the fine sand with crushed barium sulphate; similar …

The question of free will exercises readers like Tony Spottiswoode (Letters, 27 April ). But it was pretty much answered by Simon Ings, reviewing The Importance of Small Decisions ( 13 April, p 43 ). We probably all know people who can be overcome by indecision when compelled to make a choice. It can happen …

• UK TV sports presenter Dickie Davis is 86 (Almost the last word, 15 June ). • Several archaeological sites in Turkey are called Yazılıkaya ("inscribed rock"): for a photo of the one with a possible Hittite calendar, see bit.ly/NS-Hittite ( 22 June, p 8 ). • Human rights charity the International Coalition to End …

Donna Lu makes claims about Singapore's Protection from Online Falsehoods and Manipulation Bill (POFMB) ( 1 June, p 23 ). Minister for Education Ong Ye Kung and other Singapore officials have said that POFMB can't affect expressions of opinion, since it covers only false statements of fact. It follows existing jurisprudence that defines what a …

Graham Lawton notes the potential for common ground between science and religion on climate change ( 22 June, p 24 ). The Anglican church defines its mission in five areas. The fifth, added in 1990, is "to strive to safeguard the integrity of creation, and sustain and renew the life of the earth". Climate change …

It is generally accepted that Pope Francis publishing the encyclical letter Laudato Si six months before the 2015 United Nations Climate Change Conference had a material effect on the resulting Paris agreement. This isn't forgotten by the Global Catholic Climate Movement .

Donna Lu reports a scheme to capture the carbon dioxide from industry "before it enters the atmosphere" and produce animal feed by growing bacteria on it.( 25 May, p 12 ) But if CO 2 from fossil fuels is captured, used to make either carbohydrate or hydrocarbon using solar power, then used as animal feed …

Adam Vaughan describes seeking willow seeds to deposit in an underground vault ( 25 May, p 13 ). In 1992, I studied Salix alba in the cold, arid conditions of Ladakh in India and observed that the seeds lose their viability six to seven weeks after collection. I noticed a reduction in germination after 14 …