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As someone who completed a PhD in organometallic chemistry in the late 1960s, I was immediately drawn to your interview with Omar Yaghi about metal-organic frameworks (MOFs). One time I was leading a curriculum development project in which pupils aged 14 to 15 were required to design, but not make, products and services they considered …

Ernest Ager remarks that a "one in a billion" chance of life arising isn't as much of a hurdle as Bryn Glover considers it to be, given the vast numbers of star systems in the universe. Since the article that this one-in-a-billion figure comes from provided no scope of space or time, it is meaningless. …

Time isn't an illusion or mystery, and we don't need an arcane physics theory to explain why it flows in only one direction. At sub-atomic to intergalactic scales, all matter is in motion relative to most other matter, as described by Isaac Newton's laws of motion, making future motion and events predictable ( 31 January, …

I have my own simple theory of time as an amateur theoretical physicist. Time is the result of the movement of matter, and the movement of matter creates the effect of time for us to measure. Any traditional clock or timepiece has a mechanism that is called its movement; even atomic clocks measure the vibration …

Regarding the sci-fi stories inspired by the "Blueprint Problem" that Annalee Newitz decries because of their preference for placing human beings at the centre of the story rather than robotic spacecraft: I have found that the sci-fi stories that made the biggest impact on me were those that asked the question: "How would I have …

The growing recognition that the human body functions as an integrated, communicative whole, rather than a collection of isolated organs, is a welcome and important development. This systems-level view helps explain why ageing and disease are often body-wide phenomena. What is especially striking is how much remains unresolved. This should encourage intellectual humility as well …

Michael Marshall speculates about how seafaring was learned. Could it have developed incrementally as rising water levels turned a society's accustomed range into a series of islands (where once there were hills), with the gaps between them developing from dry land to a swamp to a small waterway to a larger waterway and then finally …

Marshall presents an enthralling story of Homo sapiens and other humans crossing the sea as they spread around the world, but I fear he may have fallen into the trap of assuming that prehistoric peoples were simpler than their descendants. Why should farmers have more advanced tools than hunter-gatherers? A hunter who might bag game …