Â鶹´«Ã½

Cedric Lynch writes that he would need planning permission to use his heat pump for cooling (Letters, 19 January ). Heat pumps are a central part of the UK government's plan, with predictions of 20 million being installed by 2050. Progress has been stalled by the introduction of the scientifically hard to grasp concept of …

Leah Crane suggests that if art generated by machine learning or artificial intelligences is deemed by the courts to be subject to copyright then AIs could flood national copyright offices with applications ( 5 January, p 18 ). Any work is protected by copyright from the moment it is created. Providing one can demonstrate provenance, …

Discussion of cars becoming more autonomous extends to whether they benefit from back-seat drivers ( 2 February, p 16 ). But what of the additional electrical power the car needs to use to process this feedback? This load on a vehicle's battery is parasitical on its primary function as a means of transport. Could this …

Davies proposes that the laws of nature change over time. Doesn't this raise the question of whether there are "meta-laws", invariant in space-time, to which his suggested changeable laws are subject? Maybe we just haven't yet discovered some of the ultimate laws of nature.

Archaeologist Mark Collard suggests that cave art in Europe may demonstrate that people cut off fingers ( 8 December 2018, p 16 ). Some indigenous groups in Canada cut off a finger joint as a sign of mourning at the death of a loved one. For example, one Sister Thomas of Canterbury wrote to her …

Kelly Oakes describes suffering a hundred thousand kilometres of off-key lift music while riding a space elevator ( 12 January, p 42 ). At 100 kilometres per hour, that would take 42 days. This competes against a few minutes in a rocket.

Space elevators would pass through the upper atmosphere, which is kept positively charged by lightning flashes all over the world. Since the only materials strong enough to build one are carbon nanotubes and graphene, which conduct, is there not a possibility of shorting the upper atmosphere to ground through the cable? Lightning flashes would easily …

Chris Stokel-Walker asks why we can't stop drones causing airport chaos ( 19 January, p 10 ). He mentions University of Dayton researchers firing a 1-kilogram commercial drone into a plane wing. The manufacturer of the drone used responded by saying that serious wing damage to a small aircraft was shown to occur only at …

Kelly Oakes explained that forming a fatberg involves oils being saponified ( 26 January, p 22 ). That is, they combine with calcium to create hard, water-insoluble, soap-like deposits. So are fatbergs found only in areas with calcium-rich "hard" water? The editor writes: • There are supplies of calcium even without hard water, such as …

Ian Simmons says satellite dishes in the northern hemisphere point south (Letters, 12 January ). The direction in which a dish points depends upon the location of the dish and of the particular satellite from which it receives a signal. This can be significantly different from due south.