Editor's pick: No one need own a driverless car
I can see some advantages to driverless cars (16 January, p 20 and Letters, 13 February), most promisingly that they might spark a shift to ownerless cars.
An under-acknowledged blight is the land annexed by parked cars. If personal parking became a thing of the past, we might see a return to front gardens, with attendant wildlife, carbon footprint reduction and protection from pollution and flash floods. Demolishing garages could free up house-building space. And how much more free-flowing could traffic be in the absence of illegal parking?
It won't be a good time to be a taxi-driver, though.
Editor's pick: No one need own a driverless car
Driverless cars could lead to unintended consequences. At present, pedestrians are reluctant to step out into traffic: they don't want to be hit by a car. But in the future, they will learn they can freely cross busy roads. Driverless cars will stop because of Isaac Asimov's First Law: “A robot may not injure a human being or, through inaction, allow a human being to come to harm.” Gridlock will ensue.
Gravitationally waving goodbye
So gravitational waves have finally been detected, but I feel slightly let down by the tiny “chirp” that signalled their presence (20 February, p 8). I am curious about the period of the wave: was the signal compressed, and if so, by how much?
Why would a wave have been expected at all? Surely the universe contains numerous other sources of gravitational waves, so would these waves not have interfered with each other constructively and destructively? If so, how much information can actually be gathered from the “chirp” when it might just be the end result of interference from multiple other, as yet unknown, gravitational wave sources?
You can't flee an Unruh-ly black hole
Anil Ananthaswamy reports on a resolution of the black hole firewall paradox (30 January, p 14). He suggests that for someone to stay put at a black hole's horizon, they would have to keep accelerating away from it – and that the Unruh effect, in which an accelerating observer sees an apparent rise in temperature, would create the appearance of a firewall to this observer. He reports that in the vicinity of a black hole the Unruh effect “can be as high as 1010 kelvin”.
It could, mathematically speaking. But by my calculation, our observer would have to be accelerating away from the black hole at roughly 1029 g. I believe it is safe to say that, if a black hole is massive enough for an observer accelerating away from it at 1029 g to remain in its vicinity for more than some tiny fraction of a second, the observer is probably already within the event horizon. And they would experience such tidal forces that they wouldn't be observing much of anything for very long.
Psychoactive legal logic, unravelled
Eleanor Bath thinks that proteins in seminal fluid are manipulators of female behaviour (13 February, p 27). This clearly brings them into the ambit of the UK (30 January, p 26).
Sexual intercourse (and other methods of introducing these substances to the body) will presumably be banned by default when that .
Psychoactive legal logic, unravelled
Whatever criticisms can be made of the Psychoactive Substances Act, the mechanism of banning everything and then allowing exceptions is relatively fail-safe. One example is the UK , which that is, or might be perceived to be, a degree. It goes on to make exceptions for bodies on a list maintained by the Department for Education.
Votes, not vetoes, eject politicians
Jeremy Marchant raises the idea of deselecting parliamentary candidates on the basis of ability, calling for “an independent system that culled the 50 most useless politicians each year” (Letters, 20 February). We have a system called democracy that culls them in hundreds every five years, run by the people directly affected by their legislation. I would trust the electorate to get this right, rather than a small “independent” body whose members, by the same principle, would be recruited by a yet more powerful “independent body”, whose members would be recruited…
Save lives with cord blood donations
Your article about the efficacy against cancer of stem cells taken from umbilical cord blood makes encouraging reading (13 February, p 17). The Anthony Nolan Trust has long recognised that cord stem cells have the potential to save the lives of people with blood cancer, and our research has been helping improve treatment outcomes for many years.
As the stem cells in cord blood are immature, they can develop to suit their recipient. That makes them important for patients from ethnic minority communities that are under-represented on the adult donor register.
Cord blood is not the solution for everyone, but our four cord collection centres, together with those run by the National Health Service, are expected to meet UK demand. Donating cord blood is painless and risk-free. Parents can visit to find out more.
Hungry plants flower more, but…
Hazel Beneke points out that plants reproduce more under environmental stress, and asks: “are humans an exception to the rule?” (Letters, 6 February). The answer is that all mammals are an exception. Plants are rooted to the ground but their seeds are dispersed, so fruiting offers seeds a chance to find more fertile ground. In contrast, mammals can seek out more hospitable environments. Reproducing in bad times is counterproductive for them, since their offspring are tied to their mothers while suckling, making the food shortage worse.
Many female mammals cease to ovulate when starving – we see this in humans in cases of anorexia or in athletic training. Many species, from marsupials to rodents, can keep an embryo in suspended animation (diapause) until conditions are more favourable for its development.
First class post
快猫短视频s can't stop at gravity and black holes and the spacetime continuum, you know
James Gleick that mice watching movies on iPods prefer action to mouse erotica (newscientist.com/article/2077351)
Language thinking about thought
Alan Larman asks who said, “Teach me a man's language, and I shall know how he thinks” (Letters, 30 January). A version of the idea might have been first expressed by Wilhelm von Humboldt in the 19th century, but it reminds me of Jack Vance's 1958 novel .
This tells of an experiment to devise customised languages to create warrior, technical and mercantile classes. Mastermind Lord Palafox says: “We must alter the mental framework of the Paonese people, which is most easily achieved by altering the language.” Later, his son says to a class of linguists, “every language impresses a certain world-view upon the mind.”
Language thinking about thought
May I suggest that the quote is a subconscious rearrangement of one or more of the following:
“If you talk to a man in a language he understands, that goes to his head. If you talk to him in his language, that goes to his heart” – politician Nelson Mandela; “Learning another language is not only learning different words for the same things, but learning another way to think about things” – journalist Flora Lewis; “Language shapes the way we think and determines what we can think about” – linguist Benjamin Lee Whorf; “If we spoke a different language, we would perceive a somewhat different world” – philosopher Ludwig Wittgenstein. Larman's version is certainly snappy.
Language thinking about thought
So if I master Aramaic, will I know how Jesus thought?
Horses no slouches with emotions
It would be no surprise to a horse owner that horses can recognise emotion (13 February, p 7). I would say they can recognise joy, pain, sadness, frustration and anger, not just from a photo but also from body language. Injury caused by the horse to its owner, such as a squashed foot, produces a reaction I can only describe as apology. That they recognise human faces from photographs is amazing, as other animals do not.
I remember being taken to the local drive-in cinema as a child, to see National Velvet. A string of racehorses from a nearby stables arrived in the row behind. They naturally ignored most of the film, but became very excited when the race began, neighing and dancing around. More of the audience were watching the live horses than the ones in the film.
Through normal channels, please
Martin Greenwood's nice juxtaposition of the Latin for “year” with the fundament (Letters, 16 January) reminded me of the father who received a letter from his son's private school, informing him that fees had risen by £500 per annum.
Unfortunately, someone had typed “per anum”. The father wrote back saying he would rather pay through the nose, as usual.
For the record
The authors of a study on the “backflow” of DNA into Africa from Eurasia have issued a correction (), saying that it affected East Africa and a few sub-Saharan populations, not the entire continent (October 2015, p 19).
We can't blame artificial intelligence for the misnaming of researcher (20 February, p 22). Sorry.