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Bryn Glover wonders what causes switches in perception such as that over smoking (Letters, 10 November ). Tipping points in risk perception are not unlike triggers that set off revolutions. It may be a single event or news report. One Tunisian market trader, Mohamed Bouazizi, set himself alight to protest corruption and his inability to …

The LIGO and Virgo collaborations wish to give our perspective on what we see as inaccurate claims about the robustness and transparency of our research in a recent article by Michael Brooks ( 3 November, p 28 ). We did contact Andrew Jackson's team both before and after the posting of their article on the …

One imagines that people on those planets once had a vote to be better off on their own Jennie Kermode responds to our report of the discovery of two new rogue planets that do not orbit stars ( 17 November, p 19 )

Sean Confrey raises some interesting questions about wind farms and their possible effects on the weather (Letters, 3 November ). While it must be true that any obstruction to the wind will have an effect, such effects must surely be very small, on the same order as the effect a row of very tall trees …

Philip Ball says Stephen Hawking told us that God is all about explaining the origin of the universe and responds that no theologian ever did this ( 20 October, p 44 ). As a former Christian who regularly debates such things with theists, it seems to me that Ball is out of touch and struggling …

Michael Cook complains, rightly, about games developers working excessive hours ( 27 October, p 24 ). He notes that the economist John Maynard Keynes predicted that automation would lead to shorter working weeks and this hasn't come to pass. The problem is by no means confined to the technology sector. Those in employment are expected …

Michael Marshall thought he was weird experiencing autonomous sensory meridian response (ASMR) while watching towel-folding ( 3 November, p 35 ). In a life spent in laboratories, I used to get exactly that tingle when engineers came to fix or service any piece of electrical equipment. I would find myself in a trance-like state that …

Daniel Cossins discusses the possibility that Inca khipu might encode stories as well as numbers ( 29 September, p 33 ). Apparently those master navigators and peerless blue water sailors the Polynesians used knotted cords to encode sailing instructions and these have been used for modern trips in recreated voyaging canoes. It seems the Polynesians …

Rosemary Sharples asks whether the lack of pollution at the point of use of electric cars makes their drivers feel entitled to make more and longer trips (Letters, 27 October ). It is true with me. My mileage in my Nissan Leaf is greater than it was in my previous fossil-fuelled behemoth. I now make …

Michael Marshall discusses the "brain tingles" of autonomous sensory meridian response or ASMR ( 3 November, p 35 ). It seems these were what Vita Sackville-West, lover of her fellow-writer Virginia Woolf, had in mind in her 1950 radio talk "Walking through leaves". As well as the sensation of the title, she mentioned the silky …