Editor's pick: Listen for radio signals to find alien worlds
Leah Crane reported on Hector Socas-Navarro's work on using geostationary satellites as a means to detect potential civilisations across the galaxy (17 March, p 16). He calculated there needed to be between 10 billion and a trillion in orbit to be observable.
This had me reaching for an envelope to write on. Earth's geostationary orbit is approximately 250,000 kilometres in circumference. A trillion satellites, each with a 1-metre radius, will result in about 8000 in any cross section of the orbit. Packed solid, this cross section would be 200 metres in diameter. Of course, each satellite must be free to move up and down and from side to side. If allowed a bit more elbow room, the size of the cross section would increase further.
Scaling back a bit, the (geometric) mean of Socas-Navarro's range is 100 billion satellites. Assuming each is 100 kilograms and a launch can lift 10 tonnes, that is a launch a day for over 2.7 million years.
Perhaps we should stick to trying to listen for radio shows like The Archers coming from Alpha Centuari.
Schools still need to test for colour blindness (1)
Following on from your article on colour blindness (17 March, p 38) and as someone with fairly severe protanopia (a reduced sensitivity to red light), I was dismayed to read elsewhere that screening for colour blindness in UK schools is at best patchy.
Affected children will be unable to create or understand a normal colour scheme, may be unable to tell red text from black on a computer screen, and when presented with concepts like blue vs purple, pink vs grey, green vs red vs brown vs orange could well have no idea what the teacher is talking about. They probably don't understand the fuss about autumn or pre-Raphaelite art.
They would have no idea that colour is an aspect of food preparation or presentation. They can't deal with status lights that go from red to yellow to green and could be totally at sea with colour-cued teaching aids and apps.
Most teachers will be in contact with pupils who are significantly colour blind even if they don't realise it. They need to know who these children are and understand the world from their perspective to avoid letting them down.
Schools still need to test for colour blindness (2)
It is worth noting that what you describe as “full colour vision” in humans is nothing of the sort, and that colour blindness is a relative concept. Humans usually have three types of colour cone, so are trichromatic. But some species have four colour cones, making them tetrachromatic. In a world of tetrachromats, trichromats would be considered colour blind.
Computer screens are able to use the three primary colours of red, green and blue to cover the range of human colour vision, , for whom a fourth would be needed. We see a mix of red and green light as yellow, but this isn't objectively the same as pure yellow light. It is an example of our own “colour blindness”.
Sharing renewables on the back burner
Alice Klein's look at the use of batteries for storing renewable energy and sharing it in South Australia is full of hope, but premature (10 March, p 22). A week later, an election put a conservative government in power.
We have had two major power failures here recently – one when pylons blew down, the other when the regulator decided not to start a spare generator, explaining that a “state of emergency” hadn't been declared. Federal and state conservatives blamed both on renewables. So the state will get a new interconnector to bring in electricity from elsewhere, solidifying our dependence on polluting energy sources.
First class post – 7 April 2018
Mmm! Can't be any stranger than that found on Earth
Hesling Laolcom reacts to discussion of the weird life that alien seas on Titan could host (24 March, p 40)
Are chimps born with a sense of morality?
Anil Ananthaswamy reports that 4-month-old infants expect adults to comfort crying babies, suggesting that we may be born with a foundation of morality (17 March, p 15). It would be very interesting if similar experiments were done on infants of other primates, such as chimpanzees, bonobos and macaques, as this could throw light on whether such instincts predate humans, as ethologist Frans de Waal suggests in The Bonobo and the Atheist.
Worrying message on antidepressant use
Clare Wilson took a look behind recent headlines declaring that antidepressants really do work (3 March, p 27). Those headlines, based on a study of hundreds of trials of these drugs, seemed to add up to a call for an increase in the use of antidepressants. Up until then I had been hearing a lot about their overuse and that doctors were seeking to cut back.
This is especially bad when we consider the current emphasis on mental well-being. It worries me that there may be a push to suppress symptoms with more drugs rather than to seek cures for the problems people experience.
A weekend lie-in may leave you feeling groggy
Your leader advised us to have a good lie-in on the weekend (24 March, p 5). This was also a minor option in your look at dreams, suggested as part of point one in “Can you boost your dream power?” (p 34). But point five emphasised the need to maintain a regular sleep schedule. Sleeping in on the weekend resets your biological clock, so on Monday you wake up groggy, accident prone and more dream-deprived.
The editor writes:
You shouldn't regularly sleep in longer at the weekend than you do during the week – but an unexpected upside of doing it every now and again is the boost of dream sleep.
Milgram's findings have long been questioned
Gina Perry describes how Stanley Milgram's flawed research on obedience “has been absorbed into our culture” (17 March, p 43).
Still, 快猫短视频 can be proud that 40 years ago it did its bit to question it. In 1974, it published my review of his book, Obedience to Authority (). I wrote: “Anyone who presumes that a social psychologist can in an hour's experiment turn a person into an automaton betrays either extraordinary arrogance, or insensitivity to the complexities of human action… Much of the experimental evidence could be explained in terms of the subjects' (justified) belief in the superior knowledge and experience of the experimenter – the belief even if unformulated, that the experimenter knew something that they did not. As Milgram himself confirmed… almost nobody to whom the experiment was described was prepared to credit that ordinary people would behave so brutally. How much better reason was there for the subjects themselves to doubt that torture is a routine part of Yale's psychology programme.”
Time to rethink our industrial civilisation (1)
The prospects of meaningfully tackling climate change by capturing and using carbon dioxide seem slim, as Michael Marshall states (17 March, p 34). He quotes Peter Styring as bluntly stating that stopping burning fossil oil is the only solution.
In addition, a participant from the Sackler Forum is quoted as saying “Carbon dioxide is the only gas we can emit into the atmosphere with impunity”. Maybe no tax currently applies, but we are paying with ocean warming and acidification, climate chaos that may swamp our resources, mass human migration from uninhabitable zones, loss of food production… need I go on? There are no free lunches on this planet. The whole basis of industrial civilisation has to be reconsidered.
Time to rethink our industrial civilisation (2)
You quote Peter Styring on possible uses of carbon dioxide, saying: “I can take a slurry of calcium oxide, put CO2 into a bottle, shake it up and it'll react very quickly [to make calcium carbonate].” Yes; but how does he get his calcium oxide? It's made by heating calcium carbonate. This looks like a chemistry version of perpetual motion.
Minds greater than ours are watching us like bugs
Alastair Malcolm says extraterrestrials may be shy of contact with us out of fear of another technological civilisation (Letters, 3 February). Equally, perhaps Earth is nothing special. Life forms inconceivably more advanced certainly exist and perhaps observe us. But why should they wish to engage in two-way communication, any more than we do with ants or social bacteria?
Lots to do before a fluid universe gets my vote
The idea of describing space-time as a fluid undergoing phase transitions (17 March, p 30) sounds suspiciously like a “luminiferous ether”, the all-pervasive medium on which electromagnetic fields were once believed to depend.
As I understand it, the concept was dismissed early in the last century in favour of relativity. And so there are plenty of experimental tests, whose existing results support relativity and contradict the ether hypothesis, that the new space-time fluid idea needs to explain before it is extrapolated to the beginnings of the universe.
In this case, less may well mean more
Further to your story on lowering the amount of nicotine in US cigarettes by a third (24 March, p 6). I would think, as a first approximation, that would raise the number of cigarettes smoked by 50 per cent. That would increase the amount of tar inhaled by 50 per cent, which is what causes the harm.