Letters archive

Daniel Elkan's thought-provoking article on the science of joke appreciation led me to think of some interesting questions (30 January, p 40) . There is a large class of jokes, such as those that focus on social or cultural stereotypes, where the joke-teller and listener share a sense of superiority over the object of the …

Your editorial and Stephen Battersby's article (23 January, p 3 and p 28) raise questions about possible modes of communication with intelligent alien communities and the potential dangers of transmissions from Earth into near space. There was also an excellent article by David Shiga about hidden asteroids (23 January, p 10) , for which there …

In Stuart Clark's article on the possibility of sending exploratory missions to Mars's moon, Phobos, Scott Maxwell suggests that he would be happy to go to Mars and that NASA need not worry about bringing him back (30 January, p 28) . We need not consider such a suggestion to be suicide exploration. The pertinent …

Paul Marks describes how researchers plotted alternative routes for the UK's motorways using the feeding habits of a yellow slime mould, Physarum polycephalum (9 January, p 19) . In an experiment in 2001 we found that Escherichia coli migrates by following the shortest line along a food "gradient" from low to high concentrations of nutrient. …

In his article on the dangers of online banking and electronic money, Jim Giles mentions security issues with online schemes like "Verified by Visa" and "MasterCard Secure" (30 January, p 18) . However, he fails to appreciate the objective of these initiatives, which, just like other banking industry "innovations" such as chip-and-PIN, is not to …

I found the information on exercise in Clare Wilson's article on how to stay fit very helpful (9 January, p 34) , but I was confused by its diagram of metabolic equivalents. "Sex (vigorous)" was scored at barely more than the metabolic "resting rate", while vacuuming scores much higher and is considered "moderate exercise" – …

Feedback comments on John Trinkaus's research on the use of hand sanitisers at a local hospital, where he found that non-medical people were twice as likely to use the facility as medical staff (9 January) . He suggested that this might be because the medical staff were in "summer mode" and thus thinking of more …

I read Feedback's epistle about manufacturers adding scents to consumer products with some sympathy (16 January) . My wife and I recently bought a large bag of birdseed with a sickly sweet cherry odour so pungent that it permeated the entire house until we sealed it in a large plastic bag. When I come home …

• Due to an auditory aberration during his interview, we misquoted Rob Hopkins, who believes that the effects of peak oil will be felt by 2013, not 2030 as previously stated (6 February, p 25) . • We misspelled Timo Kasper's surname in our article on the perils of electronic money (30 January, p 18) …