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Like Clare Wilson, I too tried a blood glucose monitor from ZOE, partly out of curiosity and partly for potential health benefits. I wasn't too concerned about blood glucose "spikes". It was the resulting "dips" I wanted to eliminate. What I had surmised were that periods of low glucose, which felt like having a hangover, …

Reading about the use of abstract geometry in the search for a theory of everything, I was intrigued by Renate Loll's take: causal dynamical triangulation, rooted in the simple geometry of triangles and tetrahedrons ( 10 February, p 32 ). This reminds me of one of geometry's great treasures, as Johannes Kepler put it: the …

Given that the asteroid Bennu is in roughly the same orbit as we are, is it possible that the "small, ocean-covered world with conditions favourable for life to emerge" that the rock came from is Earth? Maybe created in the same impact that tore the moon from our planet( 10 February, p 8 )?

You report on the use of exercise for long covid. This condition and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) have some important clinical and pathological overlaps and a significant proportion of people with long covid also meet diagnostic criteria for ME/CFS ( 17 February, p 14 ). In new guidelines on ME/CFS in 2021, England's National …

Matthew Sparkes wonders why the ancient Greeks didn't go on to develop greater mechanical marvels than they did. I believe the answer may lie in the changing political forces of the time, as the dominance of the Mediterranean was changing from the science and knowledge-loving Greeks to the imperialist Romans. As far as the latter …

I liked David Robson's piece on subverting memories of a work session by ending with a fun task. But the assumption in a study he cites that the supposedly onerous tasks of isometric exercise, book sorting and dealing with customer complaints are "tedious" is very subjective. I get great satisfaction from sorting books and indeed …

While I worry about excessive car use, let's not forget that only in cities or large towns would you have a choice of alternative methods of transport if car use were to be made more costly. In rural areas, an affordable car is vital, as public transport is limited or non-existent. You could have food …

Dunbar suggests other people's experiences of working from home were very different from my own. Lockdowns meant no long commute each day and very few interruptions, allowing me to get more done. It is nice to work with friends, but I have friends who will remain with me beyond this job.

Physicists may have stalled in their search for the theory of everything because of the presumption that the universe is limited to three spatial dimensions. If they are now going to use geometry in their hunt for a final theory, they may be able to get somewhere by investigating the use of tesseracts or other …

The search for a neatly packaged theory of everything is fun and fascinating. It is often difficult for the average science buff to follow the brilliant work of geniuses. However, I believe that we wrongly expect there to be a lower "size" limit to our universe, which suggests a boundary – albeit usefully – in …