Editor's pick: Fears and hopes over disposing of plastic (1)
Aisling Irwin reports on trying to solve the problem of plastic waste by getting it to dissolve (19 May, p 25). However, a plastic-eating enzyme could be disastrous if it cannot tell the difference between what is meant to be degraded and material that we need to be permanent. Plastic is used in many medical, optical and dental devices. An enzyme to tackle waste could cause people's contact lenses, medical implants or dental appliances to dissolve.
It wouldn't be the first time that an invention meant to help humans had the opposite effect. If a throwaway single-use plastic product cannot be readily recycled, we shouldn't allow it to be manufactured.
Editor's pick: Fears and hopes over disposing of plastic (2)
I have come across a practical solution to plastic disposal that is obvious when you think about it. Across Colombia, the enterprise is transforming plastic and rubber waste into a construction material and for those who need them.
The trouble with the trolley problem
Clare Wilson reports a “real life” test of the “trolley problem”, in which subjects could allow five mice to receive a painful electric shock, or press a button to shock just one mouse (19 May, p 14).
As in all cases of the trolley problem, the situation is so artificial that people try to think of ways of avoiding the dilemma without actively harming anyone (or any mouse).
In the we see that the subjects found the test hard to turn down because they received course credits for it. One out of 198 people refused to take part but was still given credits.
Nearly half did not really believe that any shocks would be given – and no mice were harmed in this study. The only conclusion I can reach is that some people would behave differently in a real situation from what they say they would do hypothetically.
This will not help artificially intelligent cars decide how many people to kill (and which) when an accident is inevitable.
First class post – 9 June 2018
Asteroids squished can form a planet. Pluto is comets squished and has a comet's eccentric orbit Brinda Thomas to people demanding that Pluto, found to be comets squished together, be called a planet (2 June, p 8)
Remember vasectomy for birth control equality (1)
Lara Williams comments that a male pill will be a breakthrough for science but not for women (12 May, p 22). She does not mention vasectomy.
In my experience this allows a man to assume full responsibility for contraception without any need for interference with his body chemistry. Numerous jokes reveal, however, that vasectomy might interfere with men's self-esteem. Could it be that for some men, part of the thrill of sex is the risk of unplanned pregnancy?
Remember vasectomy for birth control equality (2)
Vasectomy is the commonest form of contraception worldwide. True, those who take it up are not teenagers but men wanting “end of family” contraception. Still, it prevents more pregnancies than any other contraceptive method.
I can understand the appeal of a male pill to men who want to avoid condoms, though it might be counterproductive if it lowers testosterone levels. Most women in my life have preferred a diaphragm, saying it does not reduce the enjoyment of sex and has no side effects.
A rational strategy would be for women to use a diaphragm until their family is complete and thereafter for men to get a vasectomy. Messing with hormones is just unnecessary.
And all shall be, in fact, above average (1)
Like everyone else, I consider myself a better than average driver (12 May, p 42). More accurately: when I am alert and concentrating, my performance is better than the average of other drivers' total performance, including their performance in inattentive moments.
And so is yours. Stated that way, we are not delusional at all. When I am not concentrating I suffer very few mishaps, because they require two things to happen simultaneously: a lack of alertness, and a chance situation in which that lapse is significant.
And all shall be, in fact, above average (2)
So “good mental health” dictates that we all overestimate our abilities. I wonder about the relationship between that and the effect reported by Justin Kruger and David Dunning in “Unskilled and unaware of it: how difficulties in recognizing one's own incompetence lead to inflated self-assessments” (). In other words, those that know least think they know most.
There is an international trade in deforestation
Fred Pearce reports that developed nations expand their forests, while poorer nations lose them (19 May, p 6). Developed countries might well use less firewood, but surely that is because they have replaced firewood with fossil fuels, hardly much of an improvement. In any case, developed countries are beginning to use firewood on an industrial scale as power station fuel – a dubious form of so-called green energy.
When dinosaurs really got reinstated as a group
Colin Barras writes that dinosaurs were “reinstated as a scientific fact” in the 1980s (5 May, p 38). But in 1974 Robert Bakker and Peter Galton published “Dinosaur monophyly and a new class of vertebrates” ().
This led to dinosaurs being widely accepted as a single distinct group. Almost all phylogenetic studies since have come to similar findings. As Bakker and I later noted, the subdivision of dinosaurs into ornithischians and saurischians has always been weak because the latter may not be a real group. Whether we currently have enough data to settle that issue is problematic.
The editor writes:
• Bakker and Galton's 1974 paper was, in retrospect, the beginning of the turning point, but it was apparently greeted at the time with a “firestorm” of controversy.
Basalt has another talent we may be able to exploit
Olive Heffernan says coating farms with basalt could cool Earth by absorbing carbon dioxide (3 March, p 26). It could have another use: making hydrogen.
Basalt contains a similar amount of iron to peridotite, common in Earth's mantle but rare in the upper crust. In peridotite, a reaction named serpentinisation produces hydrogen as iron reacts with water under pressure. The upper crust contains lots of basalt, but mining it would not be necessary. I propose fracturing it to increase its surface area, and injecting alkaline water.
This would solve the problem that basalt is much less reactive than peridotite. Once hydrogen production has ended, the rock could be used to sequester CO2 – experimental drilling to test this is under way (18 June 2016, p 16).
The doubts of a researcher I have discussed this with are mostly to do with profitability, considering the price of hydrogen.
Is going dry just a disguised way of dieting?
In your article about the effects of not drinking alcohol for a month (19 May, p 7), you noted a drop in blood pressure and a 1.5 per cent decline in weight. I am not sure that all the benefits were the result of abstaining.
Participants had previously been drinking three bottles of wine a week, containing about 1700 kilocalories. Since the team did not see any (other) changes in their diet during the study, the participants were in effect dieting.
Not just virtual training but fully simulated war
Chris Baraniuk reports virtual training environments for troops (28 April, p 8). The obvious next step is to fight the war itself entirely within the virtual world.
The future may not be part of the universe
Your letters about the nature of time have been interesting. Rod Munday suggests that the future consists of events of which there are as yet no memories (Letters, 19 May). But consider the future from the perspective of an observer just prior to the big bang.
There was undoubtedly a future as a number of interesting things have since happened, but there was no universe. Thus the future is “outside” the universe as we normally think of it, so we can forget about ever travelling into it.
And we must somehow be prevented from travelling into the past because of the well-explored paradoxes that would result.
I wonder whether this means that there is no space in the past. If there were, then we could simply walk to the past, because space is what we move around in. So space, in which our bodies and our consciousness exist, is a thing of the present and the passage of time is the transition from… er…
That iconic polar bear may just have been old
You reproduce a widely circulated image of an emaciated polar bear limping across a barren landscape (10 February, p 35). I often wonder whether it simply shows an old animal near the end of its natural life. This by no means detracts from the importance of understanding and mitigating the effects of climate change, but large animals with few predators, such as adult bears, presumably often die from old age even if we rarely witness this in nature.
An old saying can teach a dog new tricks
Danny Chambers quotes William Hutchinson, an advocate of positive training for dogs: “Be to his virtues ever kind. Be to his faults a little blind” (10 March, p 24). Is this epigram the ultimate in doggerel?