Â鶹´«Ã½

In "The light that came late" (15 August, p 26) Anil Ananthaswamy cites esoteric theories based on string theory and quantum gravity to explain why high-energy photons from extremely distant gamma-ray bursts appear to arrive later than lower-energy photons produced in the same event. I would suggest a simpler explanation for this phenomenon: optical dispersion. …

I agree with Cedric Griffiths (22 August, p 24) , Frank Jackson and Peggy Conroy (25 July, p 26) that war is significantly driven by the profit motive. But unlike Griffiths, I can only imagine captains of industry uttering hypocritical oaths, rather than the Hippocratic ones he suggests. Indeed, a "do no harm" law would …

Andy Howse suggests that sea waves lose energy because they have to lift the water against the force of gravity (8 August, p 25) . All mechanical waves involve an interaction between the inertia of the supporting medium and the restoring force particular to that wave; in this case, by the rise of the water …

We read Katrina Voss's article on open access to genomic information (22 August, p 22) with great interest. Summing up her argument, she quotes her father: "I'm not worried, I'm just not that important." Narcissists aside, we can all agree that we aren't that important to the rest of the world. However, what Voss fails …

Rosemary Bentley suggests that a substantial degree of confusion exists over whether a peanut allergy also extends to nuts (29 August, p 26) . Although I do not suffer from peanut allergy myself, I work with a large number of people who do. While it is correct to say that some are unsure whether they …

I agree with Mark van Vugt's well-reasoned, sensible and logical proposals for overcoming the environmental tragedy of the commons by everyone working together (22 August, p 40) , but I doubt that this will spontaneously happen within the few short years we have left before we become overwhelmed with tipping points. I can only assume …

On re-reading Anil Ananthaswamy's article on melting Arctic ice caps (4 July, p 28) , I realise I haven't seen any mention of the Earth's rotation in connection with global warming. If a mass of meltwater sufficient to raise global sea levels by several metres spreads out from within 1600 kilometres of the Earth's axis …

Rick Jefferys writes that "individuals can have significantly different gut flora and other digestive capacities" (15 August, p 22) . A doctor told me of a patient aged about 50 who ate enormously and yet remained exceedingly thin. When he had his appendix removed, the surgeon had a routine look around inside the abdomen, and …

I must agree with Perry Bebbington in supporting your coverage of cold fusion (5 September, p 27) . Much of chemical practice arose from the alchemical search for a "universal solvent" and the philosopher's stone. Astronomy has its roots in astrology – one could go on. The true opponents of progress are conservatives who fight …

What makes Sophia Dunn think that hoofed animals do not pick their noses (5 September, p 26) ? Cows do it all the time – with their tongues.

• The research into the effects of railway privatisation in the UK was published in volume 60 of Social Psychology Quarterly , p 355, not volume 63 (22 August, p 40) . • The feature on other dimensions included a quote from Roger Penrose (29 August, p 34) . The words are indeed Penrose's but …