Letters archive

I was interested to read about Graham Lawton's life-affirming trip to see research work in Uganda. He mentions the climate crisis and his guilt about the long-haul flight required to get there. The balance of the piece cogently explains the steep scientific cost if research communities were to adopt a moratorium on long-haul flights( 3 …

Since antimatter is identical to matter flowing in the opposite direction through time, my assumption is that the mirror universe is filled with antimatter. So, a key question posed for our universe – "where has all the antimatter gone?" – is answered( 28 January, p 38 ).

Knowing the scientific world's love for new names to describe its shiny new concepts, it is surely just a matter of time before the mirror universe gets this treatment. Perhaps it will become known as the "mirroverse" or maybe the more accurate "biverse"?

Will our universe and the mirror universe ever stop expanding away from each other and instead start accelerating back together, perhaps due to some underlying force of attraction between the two? Might a collision of these universes lead to a so-called big crunch scenario, spawning another big bang?

In the movie Terminator 2: Judgment Day , the villain of the piece is the T-1000, a killer robot composed of a shape-shifting metal alloy. There is clear resonance here with the robot created by Carmel Majidi and his colleagues( 4 February, p 12 ). Is this a case of science fiction in the process …

Reader Nick Canning says the aether theory was "ascientific"( 28 January, p 54 ). However, this theory was one of the most fruitful in the history of science. It was useful during the development of electrodynamics, allowing James Clerk Maxwell to perceive light as electromagnetic. Mathematical and mechanical models of the aether enabled physicists to …

I understand the health and ecological problems with gas stoves that are concerning authorities in the US, but it seems unrealistic to ban them in favour of electric stoves. In the 1970s, my flatmates and I would huddle round the gas oven to keep warm during power cuts. Amid warnings of power cuts in the …

It occurred to me on reading your report about Bigfoot sightings correlating with higher numbers of black bears in the US that if I belonged to a small, endangered family group of surviving Sasquatch, the last place I would choose to live would be somewhere that is rife with competing bears( 4 February, p 11 …

You report that a small base of six people at the Martian poles could support themselves energy-wise with a combination of solar power and well-placed wind turbines( 7 January, p 13 ). This should come as a relief to anyone who has read How To by Randall Munroe. In the chapter "How to Power Your …

If the OpenAI company recorded all the responses its ChatGPT AI sent to students who get it to write their homework, it could easily provide a service for schools to check their essays. This might allay fears that it will be used to cheat( 21 January, p 15 ).

In your look at how the AI ChatGPT is being used to find and fix bugs in computer code, I had to chuckle at the quote: "We don't want to rely totally on the AI as it is not infallible." Unlike humans( 4 February, p 16 )?

Your story on the potential for using human waste as fertiliser is a bit late. Houston has been bagging up our dried sewage and selling it as fertiliser under the name Hou-Actinite for decades. It is recycled, natural and all organic! If you ever come to Texas, I can show you where to buy a …