Alien cryptocurrency may need a mega power source
I have been wracking my brains to think of something requiring the amount of power provided by a Dyson sphere 30 January, p 44. On considering recent news articles, however, the answer finally dawned on me: an alien mega civilisation that has based its entire monetary system on a bitcoin-like blockchain.
More worries about the risk of disease spillover (1)
Your leader and the associated feature “Spillover” (p 41) appear to lay the blame for the pandemic primarily on our destruction of biodiversity and encroachment on fragile ecosystems Leader, 6 March. Yet for most of human evolutionary history, people have lived within such ecosystems in small groups as hunter-gathers and would surely have been just as exposed to zoonotic infections.
The difference then was that these tribes were mostly isolated from one another, with only occasional contact. In contrast, almost all human groups are now deeply interconnected. This factor was arguably just as important in making the pandemic possible.
While preventing the destruction of nature is vital, doing things like figuring out how to quickly break the chains of transmission across the interlinked global human population should also be made a priority. After all, the next pandemic might not spawn from zoonotic sources, but something more malign like bioterrorism.
More worries about the risk of disease spillover (2)
We agree with your article on the problem of pathogens spilling over from animals to humans as we encroach on nature. There is another big factor influencing zoonotic disease emergence, though: the intensification of food animal production.
Escalating demand for animal protein means the density of livestock systems is increasingly high. Consequences include pollution, monoculture (for animal fodder), poor animal welfare, high pathogen growth and genetic adaptation. Moreover, to compensate for poor husbandry and biosecurity, more than half of antimicrobials used on the planet are in food animal production, adding to the “silent” pandemic of antimicrobial resistance.
It has been known for years that highly intensive systems increase the risk of food-borne disease and spillover of zoonoses with pandemic potential, such as avian flu. The SARS-CoV-2 pandemic has raised awareness, but we must recognise the interaction between components in eco-social systems that generate zoonotic disease risks. In that context, future development of food animal production is a major priority.
Could non-viral factors look like long covid?
While it is possible that the symptoms described in your look at long covid in children are due to this syndrome, they could also be caused by a lack of social contact and education, limited opportunities for exercise and sunshine exposure, constantly hearing apocalyptic news reports, being cared for by stressed adults, being forced to spend long periods looking at screens and so on 27 February, p 10.
Extended mask wearing will hamper the recovery
Those of us who wear glasses can suffer badly from lenses steaming up while wearing a face mask 6 March, p 10. It is a nuisance when doing something necessary like shopping. Given the talk of masks being required until 2022, I certainly wouldn’t pay to go to a concert, the theatre or a museum if I could only see a blur. So, when these places reopen, many of us wouldn’t want to go if masks are still mandatory.
Reduce and reuse is the only plastic bottle remedy
You reported research that found 2.3-litre plastic bottles are the least harmful to the planet 6 March, p 23. But why advocate an optimum size at all? We shouldn’t create loopholes for the production of harmful plastic products. The best way to prevent harm is to reduce use of plastic bottles and switch to reuse and refill business models.
Why do we think about time as two dimensional?
I read Julian Barbour’s article on the possibility of time flowing backwards with great interest, as I have recently been wrestling with the same questions (from the point of view of philosophy rather than physics) 6 March, p 46.
However, it raised questions that weren’t addressed. If time, like space, is expanding from the big bang, shouldn’t it also be expanding in all directions, not just forwards and backwards? What are the implications of a universe in which time is expanding sideways? Is the forwards/backwards concept of expanding time the result of our linear experience of time and our inability to think in other terms?
For some, exercise is the key to keeping weight off
My own experience differs from some of the claims in Herman Pontzer’s article on human metabolism, particularly the lack of weight loss caused by exercise 27 February, p 32.
In my teens, I took up running. When my children were of school age, I had less time to run and I really put on weight 鈥� about 25 kilograms. Once school duties were out of the way, I started running again 鈥� about 5 to 10 kilometres at least five times a week 鈥� and my weight went right back down. Then I injured my knee. It was operated on, but I am now unable to run and that 25 kilograms returned. I know many people like me who have to exercise or they will put on weight.
Spin a yarn in the battle against garden slugs
Here is a tip for Clare Wilson to keep the slugs at bay 27 February, p 49. My wife grows crop after crop of pristine green beans. Her secret is to pack pieces of hand-spun fleece yarn around the bean stems. This has successfully deterred the gastropods from adding her Phaseolus vulgaris to their diet.
For the record
In our report on life found underground (27 February, p 14), we should have said the deepest previously known life was microscopic nematode worms.
It is the sun’s increasing energy that will warm Earth in the far future (6 March, p 12).