Editor's pick: Many histories of a water molecule
You tell the life story of a water molecule from a comet to the present day far too simply (14 November, p 31). There is in fact no such thing as the history of a single water molecule. We know from quantum mechanics that every time two water molecules collide in the ocean 鈥� one going left and the other going right 鈥� there is no true account of which one went left and which one went right. In colliding, they become a mixture and lose their identity 鈥� inasmuch as they ever had one.
So a water molecule in the full stop of your journal does not have one history. Through its previous collisions, it has 2, 4, 8, 16… and many more histories 鈥� the same huge set of histories as almost every other water molecule on the planet. A water molecule in my body did not pass through just one dinosaur. It passed through every dinosaur that ever had a bodily function.
Sutton, Cambridgeshire, UK
Editor's pick: Many histories of a water molecule
鈥� A quantum mechanical view might even claim the world divides at each collision, in which case we are back to one story for the water molecule. We decided to avoid that minefield and stuck to a purely classical description.
Farmers' care for healthy soil
Soils are under threat (10 October, p 43), but most farmers recognise that they are their most valuable asset and in Western Australia we take steps to keep our soils in balance. These measures include “” technology to place seeds with minimal soil disturbance, retaining unused parts of harvested crops and planting legumes in continuous cropping systems. So many farmers are adapting to the challenges presented by drought and unpredictable climate.
We have adopted a new pasture legume on our farms to enrich the soil with nitrogen. has an extensive root system, grows on many soil types and is tolerant of acid soils. No artificial nitrogen is used on cereal cropped with Serradella and this has not had a negative impact on yields. The plant can have organic nitrogen “on demand” from the soil, when it needs it.
Farmers are part of the solution, not just part of the problem.
Brookton, Western Australia
<b>First class post</b>
Great! I would feel safer if I was diagnosed by a pigeon… not a specialist…
Sylvie Tapp is at pigeons being taught to diagnose breast cancer on X-rays (21 November, p 12).
Quantum snake oil and security flaws
There has been a lot of hype about quantum computing over the years, including claims that quantum cryptography will offer better security (17 October, p 10). This comes from a fundamental misunderstanding of how cryptography works.
Our current cryptographic algorithms are already strong enough. The main weaknesses in computer system security come from mistakes in implementing the algorithms 鈥� for example, weaknesses in key management and authentication 鈥� and from sources of random numbers that are in practice not so random. Quantum cryptography addresses neither of these concerns.
Quantum processes are theoretically random. But you cannot guarantee that this randomness remains untainted on its way into the upper levels of your systems. Another claim is that quantum channels are proof against eavesdropping, or allow it to be detected. But I see this as in fact a weakness. Quantum channels, being so sensitive to the slightest interference, will likely become prone to “quantum denial of service” attacks (QDoS?), in which malicious parties introduce a few random extra interactions to make it look like an eavesdropping attack is under way. As with the boy who cried “wolf”, if the alarm goes off enough times, the guards stop paying attention to it.
Hamilton, New Zealand
They don't like to be beside the sea
Given the potential for a catastrophic rise in sea levels in the next 20 years if the West Antarctic ice sheet collapses (17 October, p 8), surely the UK government should be seeking to decommission coastal nuclear power stations rather than building more?
Horsham, West Sussex, UK
Design is the root of progress
Your Leader articles make the case for not reducing national science budgets (14 November, p 5). But it is a poor case if considered as a stand-alone issue. Science is about taking things apart to understand them; and design is about putting them back together to make a useful object. Science serves no practical purpose unless it leads to a design, and design without science is just good taste.
Buckminster Fuller’s concept of design/science is a worthy one. He said that all of human progress is determined by our ability to “do more with less”. An example of this is in the design history of the radio valve, transistor and microchip. All are gates through which an electrical signal passes in one direction, but progressively more effectively.
Science needs to be seen as the research part of the design method continuum. This starts by stating a brief, then doing scientific research, creating and constructing the design and finally gaining feedback. This is a circular rather than a linear process. The research may lead to a new brief or new design.
Sturminster Newton, Dorset, UK
Making the best of appalling events
I was inspired by your interview with face transplant recipient Carmen Blandin Tarleton (31 October, p 28). It offers a real example of determination to make the best of appalling events.
Well done on printing this challenging article. I have tremendous admiration for Blandin Tarleton.
Cambridge, UK
Brain stimulation and dopamine
I note that side effects of deep brain stimulation therapy to treat Parkinson’s include impulse control disorders such as excessive gambling and hypersexuality (24 October, p 38). These symptoms are similar to side effects reported for the main dopamine analogue drugs. Is it possible that this therapy causes the brain to release dopamine, possibly from underactive or dormant neurons?
Slough, Berkshire, UK
A bigger issue than messing up Mars
I fully understand Jeff Hecht’s call for caution over crewed space missions that might contaminate Mars with terrestrial microbes (7 November, p 26). However, although a robotic sample-return mission would help to avoid this particular problem, won’t it just create another? Wouldn’t it still run the risk of contaminating Earth with microbes from Mars, if any exist? Samples of Martian soil could certainly be sealed off properly to avoid contamination, but what about the tools and other parts of the robotic probe in contact with Martian soil?
I wonder how this risk to Earth’s biosphere could be reasonably minimised.
Vienna, Austria
Ancient caving in the dark
Donald McCoy interprets the Homo naledi finds deep inside a cave system as implying early mastery of fire, to light the way (Letters, 31 October). A simpler explanation might come from a few people, blind from early in life, learning to navigate by echolocation. A reports one person demonstrating his skill in a cave. Could such people help us investigate the possibility that echolocation skills were culturally transmitted among early hominins?
Nottingham, UK
There is also a darker future…
A basic income for all seems to be a widely assumed scenario for the future, according to Laura Smith (3 October, p 28), and Anil Ananthaswamy in his review of The Master Algorithm (31 October, p 44). I don’t see much about darker futures which seem at least as likely.
In these the “haves” may just pull up their drawbridges, using robots to supply their every need, including fending off the starving, unemployed masses living on reservations. I know this will not be a popular scenario, and it’s certainly not a desirable one, but the idea that the elite would allow governments to take away 90 per cent of their resources in order to give the other 99 per cent a comfortable life seems pretty unrealistic to me.
Kirknewton, West Lothian, UK
The internet in an older box than that
Your recent article about the ability to take a snapshot of part of the web and access it as a “web in a box” away from any internet connections (26 September, p 22) took me back to 1997 in Pakistan. The British Council’s plans to celebrate the 50th anniversary of independence were well filled with arts and culture, but lacked any technology contribution.
Pakistan then had very limited internet access. I proposed setting up copies of some of the major UK websites on servers in British Council libraries in Islamabad, Lahore and Karachi, so they could be accessed both locally and by dial-up modem.
I was allocated 5 minutes to demonstrate this to the prime minister John Major. He had to be dragged away to meet the press; I thus gained my 15 minutes of fame when he opened the “Britain on Line” project.
Lenham, Kent, UK
An Ig Nobel with a practical point
Bill Corner suggests that discovering the typical duration of mammalian urination may not just be worthy of an Ig Nobel prize but actually a useful diagnostic tool for men with prostate problems (Letters, 31 October). This sounds eminently simple and sensible, so I’m planning a smartphone app and associated gadget (on the lines of a heart rate wristwatch monitor), possibly to be called an iP.
Dursley, Gloucestershire, UK
<b>For the record</b>
鈥� That stings: the water corals inhabit is more acidic than it was, but is still alkaline (14 November, p 17).