The many facets of common sense (1)
When it comes to common sense, it is worth noting that politicians and other public figures often use the phrase in a fairly specific way. In their usage, “it’s just common sense” generally means, “I hope you will agree with me although I have no evidence to support my claim and experts in the field say the opposite”. For example, it is just common sense that the more guns you have at home, the safer you are (28 September, p 36).
The many facets of common sense (2)
Your piece on “common sense” focuses on what is common, but the primary quantity is sense. Focusing on sense instead explains most of the conflicts reported, since what each person considers sensible depends on circumstance, experience and the level of risk that they accept. Professional associations recognise the roles of each of these factors in their regulations for membership and professional practice.
The many facets of common sense (3)
The conclusion appears to be that it would be common sense to agree there is no such thing as common sense. Very Douglas Adams.
We say there is no brain microbiome
There is no “brain microbiome” in the sense of a resident microbial community present in the brains of healthy individuals. Instead, microbes enter such sterile tissues through the process of infection. While the role of infections such as Lyme disease in eliciting neurological symptoms may be under-recognised, this is distinct from the idea of a resident microbial community in the brain. Claims of up to 100,000 microbial species per sample in the brain are implausible. Contamination remains the most likely explanation for such findings (28 September, p 32).
Growing your own is still a net gain
James Wong was spot on regarding the poor economics of growing your own produce. But it is important to also consider other, non-economic, factors. These include convenience and flavour 鈥� closely linked to freshness. But perhaps most important is the availability of what you want (21 September, p 44).
More reasons why our cities are getting wetter
There are further factors that could affect city atmospheres and feasibly increase rainfall in urban areas: water vapour released by burning fossil fuels and the use of evaporative cooling (21 September, p 15).
Multi-megawatt quantities of heat and plumes of saturated air are probably being emitted into ambient air around the clock via cooling towers or evaporative refrigeration condensers. Large air conditioning systems, refrigeration-dependent factories, chilled and frozen bulk cold stores and large data processing sites all contribute.
Maybe we need to rip up the physics dictionary
Matt Strassler is right regarding words used in physics that can mislead. Changing them might go a long way to clarifying things (21 September, p 32).
For example, instead of using a word like “particle”, give it a new name 鈥� “omet” 鈥� and then list the characteristics of omets. They are atomic or subatomic in size (although may become larger); they are three-dimensional; they are flexible and stretchable; they vibrate; they spin; they may have an electric charge. When knocked out from its position, an omet can flow through and around other things, such as slits in a grid. It can separate from and merge with others, both bigger and smaller. They can, at times, surround the nucleus of an atom or even be part of the nucleus of an atom.
If you need a picture in your mind to make this work, then think of an omet as a tiny vibrating, spinning smoke ball.
Perhaps solar power could help keep the ISS in space
, Les Essarts-le-Roi, France
The ideas suggested for keeping the International Space Station aloft aren’t realistic, as they would require a lot of fuel and rockets. What might be possible is to set the ISS rotating in a way that when it is moving away from the sun (experiencing “sunset”), its solar panels would be facing the sun, and some 50 minutes later when it is moving towards the sun (experiencing “sunrise”), the panels would be edgewise to the sunlight. This would tend to increase its orbital radius due to photon pressure. But I don’t know whether it would be enough to counter drag from the very thin atmosphere where it is (Letters, 28 September).
Could it be that black holes survived a big crunch?
5 October, p 40
In the interview with Sophie Koudmani, we read yet again of misgivings about the size of monstrous black holes in our early universe, and concern at the lack of time to reach such proportions. Would it be a silly or outrageous idea that such black holes may have existed before the big bang (perhaps as remnants of previous universes that “big-crunched”), around which our own universe simply expanded and adopted?
A future of artificial food would leave us vulnerable
Rowan Hooper’s column about a future food revolution paints a seriously worrying dystopian picture. This vision would leave food production in the hands of corporations and subject to the vicissitudes of supply chains, political disruption and so on (14 September, p 24).
The creation of megafarms already means farming is starting to come under the ownership of such organisations, which is a disaster for both farming and the environment. Chemically produced food divorces us from the natural world completely.
For the record
The man pictured near the Soyuz MS spacecraft is ground crew (5 October, p 26). US astronauts Peggy Whitson and Jack Fischer and Russian cosmonaut Fyodor Yurchikhin are inside the vehicle.