Editor's pick:: Fellow geologists were critical to a fault
Your article on Dan McKenzie's contribution to plate tectonics dredged up a very unpleasant memory (25 November, p 41).
In 1964, I presented an address to the Geological Society of America showing evidence for a 10-million-year-old formation being offset some 80 miles by the San Andreas fault. Fellow scientists said my ideas were “absurd” and “impossible”, that “faults cannot possibly have that much displacement”, and “I suggest that you do your fieldwork again”. The hostile reception my paper engendered resulted in me leaving the conference abruptly, very bitter over its rebuff.
A few years later, McKenzie and his colleagues proved plate tectonics, the San Andreas was recognised as a major plate boundary, my paper was vindicated and suddenly I became an authority on the San Andreas fault.
With some 6 to 9 metres of displacement, this fault is long overdue for a huge quake that, when it comes, will be the greatest natural disaster in the history of the US.
From local change comes a global tipping point
We welcome critique of the planetary boundaries framework, yet Stuart Pimm seems to have misunderstood the concept (9 December, p 24).
Pimm wrongly interprets the framework as if it assumes and relies on the fact that biodiversity has a tipping point at the global scale. This is not the case.
Tipping points exist in individual ecosystems, but there is currently no established evidence of a global tipping point for biodiversity. The reason we include biodiversity in the planetary boundaries framework is because of the way living organisms interact with the climate system to regulate overall stability of the Earth system. Erosion of biodiversity can be expected to reduce Earth resilience, which in turn can increase the risk of crossing a climate tipping point, for example.
Human pressures on the planet now influence interactions between the climate system and biosphere at the global scale. The planetary boundaries framework attempts to identify levels of this perturbation where the risk of the Earth system as a whole changing state is increased.
The framework is certainly not meant to replace any methods of ecosystem management at the local or regional levels. On the contrary, planetary boundaries offer a complement by framing local sustainable management approaches in a global context.
First class post
I'm not going to Mars if all they brew is Budweiser! isn't won over by our online comment piece about the US beer maker's plans to expand into space
Speaking in tongues can help you evade detection
I was fascinated by your article on how your personal writing style betrays identity (25 November, p 36). Over a decade ago, while working for IBM, I created a website where employees could submit complaints anonymously.
These were usually forwarded to the person's manager. While I “guaranteed” that the system was anonymous, it was obvious to me that my manager could always detect something I had written.
So I experimented with obfuscation mechanisms. I took a complaint and passed it through Google's nascent English-to-French translation. Then I passed the French back through the French-to-English translator.
Perfect! No manager would be able to attribute the result. But unfortunately, that was because it was meaningless drivel. No doubt if I repeated my experiment now, with Google's much improved translators, the obfuscated text would be almost perfect.
Of mice and menstruation
In your article discussing the link between endometriosis and depression, you write that mice don't menstruate like people do (25 November, p 16). It is not only that mice do not menstruate, but also that endometrial cells can't enter the abdominal cavity as easily as in humans.
As someone who has made a small mountain of genetically modified mice, I can attest that there is a fibrous capsule that enfolds the end of the fallopian tubes and the ovaries. This is very rich in blood vessels, being the bane of transferring eggs between these transgenic mice. It is likely that this is an adaptation to prevent ectopic pregnancy, given the amount of eggs a mouse can produce per ovulation – often over a dozen. The lack of endometriosis is a side effect.
The right and wrong way to blow up a balloon
Douglas Heaven asks if internet balloons will help hurricane-ravaged Puerto Rico (14 October, p 4). In the 1960s, when I was studying law in Wellington, a fellow student and I found a partially filled weather balloon on our way back from the law library late one evening.
The following night, we decided to fully inflate this balloon. I changed the suck end of my vacuum cleaner to blow, and the balloon quickly inflated. I took my foot off the power button, but my flatmate said: “Inflate it even more” – then an almighty explosion.
When I had stopped the cleaner, the hydrogen had fed back into the machine and sparked the blast. Some of my flatmates had burns on their faces and we rushed them to the public hospital. How foolhardy we were. In our defence, we were law and not science students.
Nobody will shed a tear for polio's extinction
Michael Le Page rightly cites several reasons why care should be taken to avoid unwelcome consequences of using genetic “extinction” drives to tackle invaders (25 November, p 25). This includes how its proposed application to possums in New Zealand might endanger them in neighbouring Australia, where they are a protected species.
However, that surely does not apply to its potential application to the eradication of the polio virus, for example. The whole world would like to see this extinct, not least those of us who are affected by it.
The price of everything and value of nothing
Douglas Heaven's explanation of the workings of bitcoin and the blockchain was very helpful and illuminating (2 December, p 36). There were, however, two assertions with which I would disagree.
Money, in whatever form it may take, as lumps of metal, sheets of paper, conch shells or clever assemblages of binary digits, has absolutely no intrinsic value, despite any apparent difficulties associated with producing it. Money is only ever a symbol or representative of true wealth, which may be tangible such as food, clothing and housing, or intangible such as healthcare, education, justice or security. Money needs to be backed not by governments, but by goods.
Currency only has real practical value when it is exchanged for goods or services. The problem with our current systems is that they permit the trading of money itself as if it were a commodity with intrinsic value. It is claimed that value can be added to money by increasing the amount of it in circulation – such as through interest payments – but unless the supply of real wealth happens to keep pace, devaluation is inevitable.
Money dealers would cite “growth” as the source of new money, but whereas money markets always seem to expand, real markets have a nasty habit of stagnating or actually reducing, resulting in a crash when the money is revalued.
The price of everything and value of nothing
Your article on cryptocurrencies was an opportunity to clarify what money actually is. It gets close to asking that question when it states that bitcoin “won't become a form of currency until people are paid in it”.
Both Buckminster Fuller and Karl Marx as philosophers held that currency is the mechanism by which we put our labour into storage. Coal in the ground is worth nothing until the labour of many people has put it into the hearth. If this labour can be stored as a currency in the blockchain, we must ask if it is secure, if it is stable in value and who owns it.
The price of everything and value of nothing
Douglas Heaven's primer on bitcoin and virtual currencies was informative and welcome. One area of interest he did not consider is the effect that quantum computers – which can crunch data orders of magnitude faster than current computers – could have on the blockchain and mining system of these cryptocurrencies.
Time we voted for a fairer voting system
Timothy Revell says there is no perfect electoral system (18 November, p 35). But some are far better than others. Among the worst is the first-past-the-post system used in the UK and US.
The best so far devised is that known as the single transferable vote (STV). It is proportional between parties. It involves voting for individuals, not party lists. It allows for third parties and for independents. It is just about impossible to gerrymander.
Revell says that fairness sounds like a proportional system: so it does. Why not use the best, STV? Details on how STV works can be obtained from the UK's Electoral Reform Society.
Might we have too much of a good thing?
Your leader and cover story supported medical use of psychedelic drugs (25 November, p 28). But you did not discuss the legitimate concerns that easier access to such drugs is likely to facilitate and increase non-medical use and abuse.
For the record
• We need a pinch more salt in our sea water, which contains about 30 grams per litre (11 November, p 36).