This is why Finland is the happiest nation on Earth
From Ros Groves, Watford, Hertfordshire, UK
Jan-Emmanuel De Neve’s take on what makes a country happy throws up some very interesting concepts, particularly the deep human need for community. I find the most significant aspect to be that while Finland, the world’s happiest nation, emphasises the importance of a healthy work-life balance, it still has optimum economic productivity, according to De Neve (25 July, p 37).
The correlation here can’t be denied. In many workplaces, the goal of economic output appears to trump a healthy workplace environment. In-house competition isolates coworkers from each other, leaving them without a sense of belonging and leading them to fail to share ideas. The drive for longer hours and shorter breaks begets stress and exhaustion, to the point where engaging in any form of social activity outside of the workplace is shunned in favour of collapsing in front of the television.
Maybe the roots of happiness begin with increasing community spirit within the workplace, giving employees a sense of pride in their corporate achievements, trust in their colleagues and sufficient energy remaining to engage with activities in their local neighbourhood.
Eating more fish as we age isn’t the right thing to do
From Sam Edge, Ringwood, Hampshire, UK
Your article on how to eat from midlife onwards and Helen Thomson’s column on the effect of ultra-processed foods on the brain both argue in favour of regular consumption of oily fish to help you get enough omega-3. But the industrial exploitation of fish and other seafood by huge fleets of trawlers simply isn’t sustainable and causes massive damage to marine environments (1 August, p 30 and 8 August, p 18).
Plenty of plants and fungi can provide omega-3 without these ill effects. Fish, like farmed meat, needs to become an occasional treat in the Western diet, not a staple.
From Fred White, Nottingham, UK
As part of the over-60 community, am I alone in feeling a distinct sense of unease with the dietary advice for my age group: increase protein and shovel in considerable quantities of fish to serve my diminishing digestive capabilities? My generation has lived off the fat of the land, and on a hungry, vastly unjust planet, this takes the biscuit. Enough is surely enough.
Could heat and light be behind longevity hotspots?
From Pauline Keyne, Beaconsfield, Buckinghamshire, UK
How interesting to read Bill Gifford’s piece on the benefits of heat (albeit in moderation), followed by the review of the book In Defense of Sunlight (18 July, p 26 and 25 July, p 24).
It is a relief to know that getting hot and sweaty, whether in a sauna or in the outdoors, can actually be very good for us, especially as now, in the UK, we are experiencing heatwaves that could make us avoid the sunshine.
Is it possible that the so-called blue zones, places that seem to have a predominance of people living well into old age (in both senses), owe some of their magic to being in parts of the world where it is pleasant, culturally congruent or necessary to spend considerable time outdoors?
Ernest Shackleton was no villain, despite reports
From Eric Kvaalen, Les Essarts-le-Roi, France
Margaret Cuthbert reminds us of the story of 20th-century Antarctic explorer Harry McNish, who clashed with expedition leader Ernest Shackleton and wasn’t recommended for a Polar Medal. But don’t be so quick to judge Shackleton. McNish reportedly argued he was no longer under his orders after the sinking of their ship, and at times refused to work. During the journey to Elephant Island, photographer Frank Hurley lost his mittens, and Shackleton gave him his. He suffered frostbite on his fingers as a result (Letters, 8 August).
Enhanced geothermal systems have a few flaws
From Peter Cundall, Minneapolis, Minnesota, US
Your article about new geothermal energy methods makes no mention of a few factors that may seriously limit the utility of enhanced geothermal systems at depths below 8 kilometres. For example, such systems rely on fracturing by high-pressure water from the injection well. If the injection and production wells are far apart, the induced fractures are likely to extend in all directions, not necessarily connecting with the production well 鈥� leading to leak-off, so that only a fraction of the injected water is recovered (25 July, p 32).
However, if the two wells are spaced close together, the heat recovery is from only a relatively small volume of rock 鈥� leading to a rapid drawdown of temperature, which limits the production lifetime of the facility. There have been attempts at creating multiple fractures between horizontal wells, but there is the danger of a “short circuit” that limits the heat flow.
It isn’t time to dismiss dark energy just yet
From Jerre Levy, Chicago, Illinois, US
Subir Sarkar and his colleagues’ claim that dark energy doesn’t exist is based entirely on questioning supernovae measurements. However, a much stronger case for dark energy was made in a seminal paper by Jeremiah P. Ostriker and Paul Steinhardt in 1995, three years before the supernova papers that won their authors a Nobel prize (1 August, p 6).
The 1995 paper didn’t depend on observations of supernovae, but showed that the concordance of several other constraints supported the idea that dark energy is now dominant in the universe and represents about 70 per cent of total energy, which causes acceleration of the universe’s expansion. If Sarkar and his team seek to deny the existence of dark energy, they must not only demonstrate that the supernovae conclusions are wrong, but also that Ostriker and Steinhardt were.
Another pattern identified in ancient Maya calendar
From Albert Beale, London, UK
James Woodford’s article about the discovery of records of a Maya astronomer describes a calendar formula with a total length of 2920 days, noting that this is five times the Maya approximation of Venus’s synodic cycle (25 July, p 15). But it is also eight times their approximation of Earth’s solar calendar cycle 鈥� surely that’s no coincidence?
For the record
Portugal gained independence from the Kingdom of Leon in the 12th century (18 July, p 32).
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