Letters archive

Leah Crane informs us that if we want to send probes to Uranus and Neptune, we had best get a wriggle on to make the next launch window in the late 2020s and early 2030s ( 28 July, p 40 ). If we miss this opportunity, we have to wait until 2050 to get close-up …

Autism does give some of us amazing abilities but for most autistic folk it is debilitating Kevin responds to the proposition that autism can bring extra abilities – and Anna Remington is finding out why ( 14 July, p 32 ) .

Graham Lawton rightly sets about unpicking some assertions about loss of biodiversity ( 28 July, p 28 ). But he bases the discussion on whether biodiversity really is in a crisis largely on extinction rates and on whether planetary boundaries have been exceeded. He pays little attention to the loss and degradation of natural habitat. …

You report Amaia Arranz-Otaegui's discovery of bread crumbs that predate farming by a few millennia at Shubayqa in Jordan ( 21 July, p 6 ). You find it curious that bread doesn't seem to have become a staple food in the Stone Age. Aboriginal Australian people were harvesting grass seeds, native rice and nardoo fern …

Stephen Battersby discusses proposals to prevent or detect spoofing of GPS signals ( 7 July, p 32 ). What about using mobile phone cell sites? Of course they are only of use on land, but they are numerous and fixed. A system using them would be very difficult to effectively spoof as it would be …

You mention the somewhat toxic site you have chosen for your head office (Leader, 21 July ). You say that the congestion and air pollution is replicated across the country. It's quite nice where I am. You use authors from all over the world, so why insist on being in London, the dirtiest part of …

Tom Kirkwood points out that 105 is the first age at which the probability of reaching the next birthday falls below 50 per cent and illustrates the odds of living beyond this to the record age of 122 by asking who has ever tossed 17 heads in a row ( 7 July, p 24 ). …

Brian Horton mentions doctors' ties carrying germs (Letters, 28 July ). When I was a medical student in the 1950s, I noticed that gastroenterologists, obstetricians and gynaecologists tended to wear bow ties rather than knotted ties to protect themselves, rather than the patient.

Someone say it: we all know what a tie is. Just look at it sticking up from the top of trousers with a knot on the end. It says "I have a penis so I get to give the orders." I find it laughable that the people who wear them can't see that this is …

• Cold fact: the amount of carbon dioxide needed to make a Martian atmosphere is about a million cubes of dry ice each 1 kilometre across ( 4 August, p 6 ). • Alfred Russel Wallace was racked by yellow fever during his South American expedition of 1848–1852 and studied birds of paradise in the …