Letters archive

You say that around half the aluminium cans thrown away are not recycled but end up in landfill (4 October, p 34) . Then you describe plans to dig up landfill waste and sort it mechanically to separate out the contents for recycling. Why not simply take all waste material from homes and businesses to …

Your features on renewable energy (11 October, p 28) made only a passing reference to water power. From my window, I can see the giant turbines of the country's largest on-shore wind farm. They were made in Germany, taken to high moorland and erected at enormous cost. Yet in the valley below, the River Irwell, …

The Hewlett-Packard researchers' conclusion that contributors to websites are seeking personal glory rather than performing a public service (4 October, p 23) seems a very harsh and rather nihilistic interpretation of something that I see rather as another example of the altruism inherent in any healthy individual. Most people continue to try to live their …

Brian Moss suggests that all cars should be electronically limited to the speed limit (11 October, p 20) . Which country's speed limit? Is he suggesting a dynamic speed limiter, based around either GPS or transponders? How confident is he that such a system would not suddenly suffer a glitch and lose the trailing zero …

A $200 gadget to give a 19 per cent boost to engine efficiency (4 October, p 23) ? I can't believe it, and if they reduced the claim to 5 per cent I would still be a sceptic. If it only gives a reliable 1 per cent improvement competition will ensure that it is fitted …

You say that the case of the passenger pigeon in the US is a classic example of a decline of a species as a result of hunting (20 September, p 3) . While hunting did play a part in its extinction, the elimination of suitable habitat due to the industrial expansion of the US was …

I am disappointed that Stuart Clark answered the "Where did life come from?" question in your "Unknown Earth: Our planet's seven biggest mysteries" article by immediately minimising the possibility that life arrived on Earth in any of the ways that the "panspermia" theories suggest (27 September, p 30) . Max Wallis and N. Chandra Wickramasinghe, …

I was surprised to discover a new, super-heavy 22-kilogram breed of albatross exists (4 October, p 10) . I have worked with southern royal albatrosses, which are generally around 9 kilograms. These have a hard time taking off and landing, so I can't imagine how the 22-kg monsters avoid crashing! I recall a Mars probe …

• We said that "levels of carbon dioxide in the atmosphere need to be cut by 80 per cent by the middle of the century" (11 October, p 3) ; we meant to say that the rate of CO 2 emissions needed to be cut by 80 per cent. • We said that the Royal …

Tony Budd is right to criticise the kind of thinking that says, "this high-rise block of flats is designed to withstand a wind speed unlikely to be exceeded more than once in 100 years, so since its design life is 60 years, we have got 40 years to spare" (18 October, p 20) . But …

Thank you for the great article "Tools maketh the monkey" (11 October, p 42) . It seems that Douglas Adams was, again, right in The Hitchhiker's Guide to the Galaxy , where it is written: "a news report brought to you here on the Sub-Etha waveband, broadcasting around the galaxy, around the clock; we'll be …

New techniques to track HIV infection in Africa show that the virus crossed from chimps to humans as early as 1908, at a time of rapid growth in the major cities in colonised sub-Saharan Africa (4 October, p 10) . David Worobey notes the likelihood that high-risk sexual behaviours found in cities allowed the virus …

I really enjoy reading your magazine, but I am curious to know how much Virgin paid for the full page advert for "Upper Class" service (18 October, p 4). It seems to me that in an issue about the folly of growth (18 October, p 40) to advertise a hugely carbon expensive means of travel …

Your special issue on renewable energy implied that its objective is to generate electricity (11 October, p 28) . In fact, the primary purpose is to reduce the discharge of carbon dioxide. The generation of electricity from renewable sources does have merit, as even the best fossil-fuelled power stations convert only half the fuel energy …