Letters archive

Our climate and biodiversity woes represent a threat greater than a world war. As we would with such a conflict, we need to spend our resources wisely on projects that will reap rewards immediately, or at least within the 20 years or so we have to make the biggest impact ( 6 July, p 13 …

The cool fabric for clothing that you describe may be rewarding for the scientists who designed it, but could it be damaging to the environment? Its three layers – wool or cotton, silver nanowires and polymethylpentene – could be a nightmare to recycle, particularly as many people wear fashionable items for a short period and …

I have an idea related to David Robson's look at scientific rules of connection that could improve your social life. One way for pubs, parks, libraries and other social spaces to help would be to paint a large red dot on the ground. This would be a place where people who want to develop new …

Some things don't change. Our ancient ancestors valued caves as a haven from the weather and wild animals. Now, we are considering using caverns on the moon as protection from space "weather". Perhaps we should think about installing a copy of the Lascaux cave paintings in the first lunar cavern we use for habitation ( …

Having watched the first two A Quiet Place films, and reading Douglas Vakoch's lament about the irrational fears raised by the portrayal of scary extraterrestrials in the third film, I wonder if I am alone in believing these blind movie aliens aren't even remotely likely? Sharp-eared enough to hear a picture frame smash a mile …

The underlying debate is whether it is a good idea to send signals to try to reach intelligent aliens. The worry is there is no global entity that polices such transmissions and, even if there were, it would be impossible to enforce. But I agree with Vakoch that it doesn't matter because aliens advanced enough …

As a scientist, I prefer to think in terms of components, causality and processes. It would be good to know more about these when it comes to ultra-processed foods ( 13 July, p 10 ). There are many questions. Which additives might degrade the mucus lining of my gut, leaving me at risk of bowel …

Bringing back the dodo might have commercial implications because it was apparently tasty to eat. I can imagine meat producers being interested in an edible bird twice the size of a turkey, especially if its growth or reproduction rates could be tweaked ( 15 June, p 40 ).

In your look at the possibility of extra dimensions, Georges Obied says: "There's no reason why it has to be three. It could have been two; it could have been four or 10 ( 13 July, p 32 )." I wonder whether we can look to the anthropic principle as to why we have at …

As I see it, to replace a lot of fossil fuel use requires a chemical that would react, for example with water, to produce hydrogen on demand. A driver could go to a fuel station with a spent pack of this chemical, buy a new one and fit it in place and drive off in …