Letters archive

Paul Marks ends his article on robot border guards (9 January, p 20) with a question about the privacy implications of such surveillance technologies for people who live close by. There are other questions we should be asking, such as whether technology really is the answer to controlling illegal immigration. The main reasons people leave …

Ray Tallis gets it right when he argues that we are a long way from explaining the origin of consciousness (9 January, p 28) , but while he does a very good job of deconstructing some of the research and assumptions surrounding this topic, he fails to address the biggest hurdle: what does he, or …

The list of obscure or little-studied emotions in Jessica Griggs's article (16 January, p 26) barely scratched the surface. As any music-lover knows, there is a world of intense emotions out there that are impossible to verbalise or conceptualise. To experience music is to experience a separate universe, one created entirely by humans. The deeper …

Michael Le Page roundly turns on anyone who dares to suggest that the current severe winter conditions throughout the northern hemisphere put a question mark over the existence of global warming (16 January, p 20) . If that were right, he says, the sceptics would have to accept that a spell of hot weather would …

I was disappointed by David Cohen's article about the 1000 mph car (21 November 2009, p 38) : surely in this day and age you could use metric units. In New Zealand and Australia we gave up the archaic imperial measurements about 30 years ago. I know that the US and, to a lesser extent, …

I was astounded to read in The Last Word piece about how high butterflies fly (16 January) that commercial airline pilots have reported seeing monarch butterflies at between 3000 and 4000 metres. What I would give for eyesight that good: commercial airlines cruise at about 250 metres per second. How do pilots manage such feats …

In Paul Marks's article on the dangers of hackers using networks of computers to eavesdrop on conversations on your laptop or smartphone (16 January, p 17) , an anonymous "security expert" claimed that such attacks are too crude to pose a serious threat. "It is unlikely any worthwhile target will use Windows unpatched," he says, …

As an employee of a chain of pizza restaurants, I initially found Stephen Ornes's article on the mathematics of preparing perfect pizza portions highly insightful (12 December 2009, p 48) . However, as soon as I began to attempt the method it described I floundered. This only appears to work with margherita pizzas and others …

• Possessing a "grid" of brain cells that helps us to navigate might explain why some people are better at finding their way around than others (23 January, p 15) . Although these cells provide a virtual grid on which locations in the world can be represented in the brain, we should have made it …