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With reference to the interesting article by Ciarán Gilligan-Lee on quantum cause and effect, I would point out something that I have often noted, but that is always overlooked ( 29 November, p 36 ). History can be understood in quantum terms. The future is nothing but a series of probabilities, the present is where …

David Flint says biomass carbon capture would require too much land area. He favours using chemical plants to capture carbon dioxide from the air. I would like to point out that, every year, about 440 gigatonnes of carbon dioxide enter the atmosphere from rotting vegetation, whereas we have about 1100 gigatonnes more carbon dioxide in …

As a contributor to the documentary Blue Planet Red , I would like to address the criticism in Simon Ings's review that xenon-129's presence in the Martian atmosphere implies ancient nuclear conflict only if you ignore the well-understood process by which a now-extinct isotope, iodine-129, would have decayed to xenon-129 in Mars's rapidly cooling lithosphere …

Regarding the feature Songs from the caves, the Lascaux cave paintings in France include a star map of the Taurus region of the sky with a bull painted around the Hyades, just as the constellation is depicted today ( 22 November, p 34 ). Dated at 17,000 years old, surely this is the oldest provable …

The Torino scale assigns asteroids a score of 0 to 10 based on their size, energy and probability of hitting Earth ( 15 November, p 38 ).

Your feature explores the issue that nothing seems to be fixed until it is measured. Measurement can be an observation. What quantum theory doesn't explain is that it all depends on who is observing an object. That is why, after I have failed to find a particular object in the fridge, when my wife then …

I cannot agree more with Anthony Laverty's article on the need to curb the trend towards big cars. Not only are they more lethal in a crash, they are also more likely to be involved in accidents because of larger blind spots and longer braking distances. I call for regulations to inconvenience big car owners …

Laverty perfectly sums up what can only be described as the biggest environmental crisis ever to hit UK roads, and beyond. Let's hope this subject gathers much-needed momentum.

In reference to Claudia Canavan's article, "Time for a new you", I have been applying the Myers-Briggs Type Indicator – which categorises people into 16 personality types – for over 30 years ( 27 September, p 23 ). Despite often being dismissed, it has always "said" everyone is both an extrovert and introvert (just not …

Your article on giving up on your ambitions put me in mind of a passage from P. G. Wodehouse that has stayed with me since I read it over 30 years ago ( 15 November, p 28 ). In it, he succinctly summarises the gist of the article: " 'Well, well,' he said, 'if I …