Keep it clean
I question Alberto Fairen and Dirk Schulze-Makuch’s statement that planetary protection, such as spacecraft sterilisation, prevents missions from going to particular places on Mars (6 July, p 8).
Current engineering cannot get us there, and the cost of developing such capabilities is many times the cost of planetary protection. In addition, the cost of implementing planetary protection measures is less than indicated and not a major driver for a mission budget.
Apart from that, the jury is still out on the idea that natural transfer of biological material from Earth to Mars via meteorite has happened or is possible. Transfer of material from Mars to Earth is demonstrated by Martian meteorites; the reverse is unproven. Modelling indicates such a process would transfer a lower amount of material and it would have a higher physical stress on it 鈥� calling into question its ability to carry biological material intact. We also have no evidence that Earth environments with plentiful biomass 鈥� oceans and sediments 鈥� can actually form meteorites.
Existing planetary protection measures provide the necessary boundary conditions to increase our knowledge about Mars 鈥� to confirm or reject different hypotheses 鈥� and they also protect our large investment in space science and exploration, now and in the future.
Noordwijk, The Netherlands
Anger issues
Using 3D gestures to command a computer, as you report (25 May, p 40), gets a 3D gesture from me: thumbs down. I am perfectly happy with the 2D gesturing on my touchpad.
What I would like a computer to do, however, is sense my anger. I get angry when I have several applications running and the computer decides how to prioritise them, not me. I want to be able to tell it which should be handled first. After all, just who’s the boss?
Culemborg, The Netherlands
Kill the cat?
I see that the wretched Schr枚dinger’s cat has once again made an appearance (3 August, p 15). I recall as a student experiencing great difficulty getting my head around the idea of a superpositioned feline, while having only small problems with the actual physics it was supposed to clarify.
I once considered founding a society for the abolition of Schr枚dinger’s cat from the teaching of physics, but then, how would we ever know whether we had succeeded or not?
Cracoe, North Yorkshire, UK
Stem cell debate
I have sympathy for the “crusaders” who feel they are being denied treatment for debilitating conditions using their own stem cells (10 August, p 42). However, I also think that the US Food and Drug Administration (FDA) is taking a responsible position on the regulation of cultured mesenchymal stem cell transplants.
These cells are grown in a lab after removal and are not identical to those that remain in the patient’s body or are immediately reinjected. Such cultured cells will show changes in gene, RNA and protein expression and are therefore no longer, strictly speaking, the patient’s own cells.
There is a real risk such cells will neither differentiate nor replicate normally once reintroduced, potentially creating problems. Although perhaps not ideal, until a new regulatory body is in place, the FDA provides vital protection for vulnerable patients.
Fareham, Hampshire, UK
Human factor
However powerful and useful machine-learning artificial intelligence might be (10 August, p 32), such systems also have a social impact. Their development is part of a trend towards the devaluation of skilled work and intellectual labour, from applications in translation to the creative arts.
If nobody can make a living producing translations, or by writing, or making music, then there will be no more raw material to feed into these “free” AI technologies, which will be reduced to recycling their own products. Sadly, this is already starting to happen in many areas of knowledge work.
Society somehow needs to reconcile the benefits of this kind of innovation with the damage done to the wider intellectual and creative infrastructure.
Abergavenny, Gwent, UK
Human factor
Douglas Heaven inadvertently exposes the real danger of this type of AI, anthropomorphising complex algorithms. Machine learning, having no moral component, cannot be racist, as was claimed when Google’s search function ended up directing ads asking “have you ever been arrested?” towards black people.
What it did find was a correlation between having a black person’s name and involvement with the criminal justice system.
There are no profound ethical dilemmas if we accept AI for what it is, an observer of statistical correlations. I suppose it is more comfortable to call a box of transistors racist than face up to our own prejudices.
Burton upon Trent,Staffordshire, UK
Not so natural
Gerald Legg’s letter on eco-offsetting referred to greater protection likely to be given to chalk grasslands compared with disused industrial land reclaimed by nature (10 August, p 30). These grassland habitats are widely believed to have been deforested in Neolithic times, then kept in their current state by the grazing of farmed animals.
Arboriculturally, they are as much a disaster area as the worst industrial brownfield site.
Newbury, Berkshire, UK
Burning issue
Those who talk up fracking for shale gas (10 August, p 36) need to remember that we have already discovered five times more fossil fuel reserves than can be used if we are to have a reasonable chance of avoiding a 2 掳C rise in global temperatures.
We have to stop using oil, gas and coal or invest in carbon capture and storage. However, tapping shale gas generates value for oil companies, capturing and storing carbon dioxide does not.
Aberdeen, UK
Burning issue
All we will do with “fracked” gas is use it to continue avoiding dealing with climate change. So there is one fundamental aspect we need to address. We need to turn to our children and say, “So that we can save a few pennies on our bills, we’ll be using all the shale gas as prodigally as we use everything else, so there will be none left for you and your children. Sorry about that.”
Meols, Wirral, UK
Twins in space
Comparing the physical and behavioural outcomes of the identical Kelly twins, one of whom will spend a year on the International Space Station, is an ingenious idea, given the genetic control (10 August, p 11). However, it is not a novel notion.
In 1972, astronaut Charlie Duke was on the Apollo 16 moon mission, while identical twin Bill, a non-astronaut, stayed behind. In discussing these twins in my book Entwined Lives, I suggested they afforded a unique test of Einstein’s 1905 twin paradox 鈥� that time would pass more slowly for the space-faring twin.
The Dukes were actually better suited to this than the Kellys, both of whom have considerable experience of space travel. It seems the Duke brothers have been overlooked in this regard. NASA’s John Charles was wrong to say “the only twins we have access to are both astronauts”.
Fullerton, California, US
Beyond doping
The first thought that entered my mind when reading Douglas Heaven’s article on designer organs, was “won’t the athletes love this” (27 July, p 8). We have already seen the use of performance-enhancing drugs and blood-doping; this will open up a new avenue for exploitation.
Imagine an athlete who can enlarge or speed up their organs, such as the heart or lungs, or strengthen muscle fibres and blood vessels, or even generate short-lived drugs within the body. Those who police cheating in sport will not be out of a job any time soon.
Newcastle, New South Wales, Australia
Anonymity must go
Your editorial discussed how to deal with the abusive comments posted by some users of Google and Twitter (10 August, p 5). For the last 10 years in every talk I gave about the web, the early development of which I was involved in, I have argued that the only fix to such problems is a worldwide legal framework.
Rather than self-regulation, that means traceability of publisher and user 鈥� no anonymity 鈥� plus a code of conduct and enforcement of sanctions, much in the way we handle road and air traffic.
But I have also cited my first law of informatics: “No paradigm of the physical world can be transposed into the digital world.”
So the conflict between the make-up of our brains, which evolved in a physical environment, and the digital world, in which behavioural barriers seem very different, won’t be easily solved. As the editorial rightly concludes: there are no quick fixes.
Pr茅vessin-Mo毛ns, France
One tough roach
The first time I heard about the fly-in-the-urinal means of manipulating behaviour (22 June, p 32) was a story about a bar with a cure for unruly drunks. The bartender would wait until a particularly bad boy went to the toilet. There was a bare wire strung across the back of the urinal, and the bartender had a way to let a live cockroach run out on it. Of course it instantly became an irresistible moving target, but the wire was charged, and the miscreant got instant enlightenment.
Point Pleasant, Pennsylvania, US
Low blow
One solution to John Hardy’s call to ban boxing because of the long-term risk of brain damage (10 August, p 26): a blow to the head should be ruled a foul, and result in immediate disqualification.
Harlow, Essex, UK