Letters archive

Your editorial and articles on DNA testing raise the important issue of obtaining appropriate consent for an individual's DNA to be tested ( 31 January, p 3 and p 6 ; 24 January, p 8 ). The law in the UK is clear on this: it is illegal for a laboratory to test an individual's …

In the concept proposed by Marcus Chown in the article "All the world's a hologram" (17 January, p 24) , the two-dimensional surface of the sphere surrounding the universe is the hologram and the universe (including you) is a holographic image – a point glossed over by the oversimplified wording that appeared on the cover …

Mark Buchanan's discussion of "unknown unknowns" (24 January, p 32) could usefully be applied to banks' assumptions of credit risk exposure. Some use Monte Carlo simulations to calculate an acceptable level of value at risk. These use tables of probability of loans defaulting, provided by the rating agencies. One problem with this method is that …

You reported on research, based on a large number of satellite photos, showing that cattle and some wild grazing animals align themselves predominantly along north-south lines, suggesting an awareness of the Earth's magnetic field (30 August 2008, p 10) . I have since paid particular attention to the hundred or so cattle and sheep visible …

Mark Buchanan refers to humourist C. Northcote Parkinson's ideas about committees (10 January, p 38) . Parkinson's suggestions have more far-reaching applications than just committee size. When working on a project to reduce the crew workload in a large anti-submarine aircraft, I was continually being pressured to increase the crew size. In fact, such an …

I enjoyed Paul Collins's article on metal balloons down the ages (10 January, p 44) . I am not sure, however, about his remark that, since 1941, "no more metal-clads have taken to the skies". I seem to recall reading, 30 or 40 years ago, of a successful project at the Massachusetts Institute of Technology …

David Robson discussed the herd mentality in humans (7 February, p 13) . On the rare occasions that I have been to church, I witnessed the power of singing as part of a congregation and the connection you feel with those standing next to you. I found myself caught up in the moment with emotions …

• We wrongly stated that the World Health Organization recommended in September 2008 that the electronic cigarette be banned (14 February, p 33) . The WHO in fact stated that it did not consider the electronic cigarette to be a legitimate therapy for smokers trying to quit. • We said that in 1709 "from Czechoslovakia …

I read with interest your articles on genetic privacy ( 31 January, p 3 and p 6 ; 24 January, p 8 ): particularly, the assertion by Denise Syndercombe-Court that a man undertaking a stealthy paternity test is "acting for himself; he's not acting for the child." When a man and woman enter into a …

The unreliability of information on the internet does raise issues regarding its use in higher education (17 January, p 44) . I do not agree that the solution is to have "an international consortium of universities set up panels to audit the worth of websites, endorsing those that are reliable". Instead, we need to focus …

Robert Winston relates how he had been ostracised at scientific conferences as a "populariser" (31 January, p 22) . This sadly reflects not only the sometimes blinkered vision of one's fellow scientists but also the reality of the organisation of British science in universities. I know of a well known popular-science writer who left employment …

Matthew Chalmers perpetuates a fallacy that a day is the time taken for the Earth to "turn once about its axis" (7 February, p 39) . That is actually the sidereal day. However, it is not the source of our Babylonian-influenced clock units, nor what is commonly called a day. It is in fact the …

How can you print an article on the six greatest mysteries of the solar system (31 January, p 28) without mentioning Bode's law? This was first proposed by Johann Daniel Titius in 1764, then taken up by Johann Elert Bode in the second edition of his book Anleitung zur Kenntniss des gestirnten Himmels in 1768. …

Sebastian Hayes asks science teachers, "What evidence do I see around me of relativity or quantum mechanics?" (31 January, p 25) . I whirl round a bucket of water on a rope over my school's laptop. Relativity shows that gravity and centripetal acceleration are giving and taking in the same currency: the water stays in …