Letters archive

Laura Spinney's informative article on the isolation of ancient DNA (aDNA) from soil raises an intriguing consideration. Soil collected by NASA's Mars Perseverance rover will return to Earth as part of the Mars Sample Return mission, probably some time in the 2030s. I suspect I am not the only person now eagerly awaiting the analysis …

Weight-loss drugs are probably playing a part in the slight dip in obesity in the US. But like many other parts of the world, the country has seen high inflation during the past few years, which has caused a cost-of-living crisis, raising food and energy prices. The consequence has almost certainly been lower food consumption …

A colony on Mars will fail as a back-up plan after a catastrophe on Earth. It is hard to see how it could repopulate Earth with a significant number of people. Returning to Earth from space is a logistical nightmare at the best of times and requires functioning landing sites or splashdowns, with rescue by …

When I saw the image of the server robot in a dress, with a feminine chest, I assumed its appearance would be addressed. In particular, the sexist practice of casting obviously female robots in subservient roles. But it wasn't. I hope the modestly covered chest hides a pair of fembot boob missiles – she may …

Thomas Lewton is left doubting that his dog considers him a being with a mind of his own. I don't know about that, but my cat Dolcina, who lived 18 years, knew very well that humans have their own point of view on the world ( 14/21 December 2024, p 66 ). Our house is …

On the subject of ensuring the carbon in goods doesn't come from fossil fuels, what matters is the fate of the goods after use, not where their carbon came from. If you use something made from recycled plastic but then discard it and it turns into methane, you have added to global warming. If it …

Why even discuss "time" travel outside fiction? We have no concept of what "time" is or if it even exists, just measurements of events compared with each other, the decay of atoms, the movement of the stars, etc ( 14/21 December 2024, p 54 ).

Reader views on the colonisation of Mars, varied as they have been, have missed the most important point of all. Historically, colonisation was driven by a search for opportunities to trade and get rich. Perhaps, with Elon Musk as one of the chief proponents, we are missing the elephant in the room. Rather than debating …

"Bursting the bubble", about quantum ideas that could do away with the multiverse, was excellent, but it is troubling that theorists still consider Schrödinger's cat and Wigner's friend to be valid thought experiments. They assume that a human observer is required for quantum collapse, which is absurd ( 11 January, p 32 ). How did …

The report that blinking gives your brain a break by taking pauses while reading reminds me of the views of Hollywood film editor Walter Murch in his 1992 book In the Blink of an Eye ( 11 January, p 17 ). He says the difference between a good actor and a bad one is in …