ET's expiry date
The equation devised by Frank Drake to estimate the number of advanced civilisations in the Milky Way detectable by radio signals received another couple of airings last month. It was alluded to in your “Instant expert” on astrobiology (7 May), and mentioned the following week in your editorial (14 May, p 3).
The problem with drawing any meaningful conclusions from the Drake equation is that the figures for each of its terms are arrived at largely by guesswork, and even minor adjustments result in vastly different solutions.
The version that I like best incorporates an almost political factor, namely: “What is the likelihood of an advanced technological civilisation being able to survive its own acquired ability to annihilate itself?” If the answer is “zero”, then we are the most advanced type of civilisation, having recently arrived at the point of potential annihilation.
Given a slightly less pessimistic assumption, there could be anything between a few tens to a few hundreds of millions of advanced civilisations. Personally, I believe the universe is teeming with advanced life.
Vacuum's origin
Twice in his interesting article on the limits of knowledge (7 May, p 34), Michael Brooks stated that quantum uncertainty means the universe could have appeared from nothing 鈥� meaning that it could have arisen from a quantum vacuum.
But a quantum vacuum is not nothing; it is a particular kind of fluctuating energy field governed by quantum laws. Even if its average energy is zero, this is not nothing. Where did such an energy field and the laws which govern it come from?
This is a question which the UK’s Astronomer Royal, Martin Rees, with whose views the article began, recognises cannot be answered by science. As he put it in his 2002 book : “The pre-eminent mystery is why anything exists at all. What breathes life into the equations of physics, and actualised them in a real cosmos? Such questions lie beyond science, however: they are the province of philosophers and theologians.”
Just because science cannot answer some questions does not mean that they cannot be tackled fruitfully by other intellectual disciplines.
Climbing on autopilot
I’d like to add an observation consistent with Benjamin Libet’s experiments, which showed volunteers’ brains initiating movement before they became consciously aware of an intention to move, as mentioned in “The grand delusion” (14 May, p 35).
When rock climbing many years ago, I often found that while tackling a difficult move I would try several times, and then my body would suddenly go for it and be over the hard part. This often occurred before I realised it, and certainly without a conscious decision at the moment of ascent.
In no way is this an argument against free will. Delegated subconscious decisions are made by “me”, even if there is a delay in informing the control room.
The rat factor
We read a great deal in New 杏吧原创 about the world food crisis, the threat of global shortages and food wastage, as in the article by UN Environment Programme director Achim Steiner (16 April, p 28).
One important but rarely mentioned factor is that a considerable proportion of the world’s food is eaten by mice and rats. Recent studies in rice-producing countries such as Indonesia, Malaysia, the Philippines and other Asia-Pacific countries, show rats eat up to 15 per cent of rice produced ().
The UN Food and Agriculture Organization promotes the use of secure food storage, but much of the loss is before harvest.
Perhaps, like cockroaches, rodents will always be with us, but they need energetic control.
War games
Soldiers playing video games that “desensitise players to violence” might be sleeping more easily (12 March, p 25), but should the rest of us be?
You don’t have to be an expert to understand that the “more violent dreams combined with a sense of helplessness” experienced by those who didn’t play the games, were an attempt by the subconscious to come to terms with the psychological and moral conflicts evoked by the real violence in a soldier’s life.
These subconscious conflicts may even prevent a soldier from committing an atrocity, or at least make them think twice before committing one.
Trial and error
You describe the use of
computers that use evolution-like methods to create designs whose success cannot be fully understood, as part of “The next wave” (14 May, p 30).
Surely all that is being achieved is a tireless and very high-speed use of that usually derided technique, suck-it-and-see.
Need to know
“The MIT puzzle” part of the “Killer codes” feature (21 May, p 40), mentioned that the RSA algorithm was developed by Ron Rivest, Adi Shamir and Len Adleman in 1977.
In fact this algorithm had been worked out before then by mathematicians James Ellis and Clifford Cocks, but as they were working for the British government’s eavesdropping organisation GCHQ, it was kept under wraps.
From Dave Oldham
The article on uncrackable codes was fascinating, but had one glaring omission.
Has anyone yet managed to decode James Joyce’s Finnegans Wake? I ploughed through all 629 pages and never found a clue. The only word I understood was “quark”.
Northampton, UK
Carbon tomorrow
The difference between the short and long-term carbon cycles seems to be overlooked in “The rush towards renewable oil” (21 May, p 6).
Planting tomatoes and trees or growing algae only “offsets” fossil-fuel carbon emissions until the tomato is eaten and respired, the tree dies and rots or the biofuel is burned; the carbon from the fossil fuel is re-released and still eventually contributes to global warming.
The statement that “firms would no longer have to invest in technology to bury the greenhouse gas [carbon dioxide] safely” is short-sighted.
The purpose of renewable oil is to reduce our reliance on fossil fuels, not to permit their use.
Religious manoeuvre
To describe your religion in 17 characters or less on the UK census form is a challenge (Letters, 23 April, p 28). Alan Charlton made do with “ScientificRealist” (17 characters), since “scientific realist” (18), as suggested by earlier correspondent Martin Hunt, was too long. Thank the good Lord I live in California, so I am not required to reveal my religion.
But since you asked, I call myself a “secular humorist” (16), which leaves one character for future expansion. I’d be interested to see what other readers come up with.
Robo crime
Robots downloading apps to acquire new functionality (19 February, p 24)? While the idea appeals to my inner nerd, I’m afraid it may appeal to other people’s inner criminal.
Imagine the day that malicious software could result in a robot letting strangers into your house, setting fires or even harvesting your organs while you sleep.
Dream theory
Regarding the interview with dream researcher J. Allan Hobson (23 April, p 48), I like to think of brain activity while asleep as akin to a computer defragmenting its hard drive. Dreams are just some of this information transfer rising to the conscious level as memories are relocated to more appropriate locations.
Going quackers
On the subject of the supposedly outmoded “air scribble” gesture used to request a restaurant bill (Feedback, 9 April), the scribble is not completely redundant yet. Bills are still sometimes signed for when paid with a credit card.
However, I still prefer my business partner’s method: he gets the waiter’s attention and then pretends to stroke an invisible duck’s bill attached to his face. It never fails to confuse, but always gets attention.
Ad space
The “Drive-by advertising” story (7 May, p 24), which mentions safety fears about turning car windows into billboards, reminded me of a passage in an old sci-fi novel.
by Cyril M. Kornbluth and Frederik Pohl, published in 1953, describes a time when advertising companies dominate the world, and includes the quote: “They listened to the safety cranks and stopped us from projecting our messages on aircar windows 鈥� but we bounced back. Lab tells me… that soon we’ll be testing a system that projects direct on the retina of the eye.”
Watch this advertising space.
For the record
鈥� In the feature on gut microbes (14 May, p 42), the figure in the first paragraph was wrong. It should have said the bowel disease necrotising enterocolitis kills up to 5 per cent of premature babies.
鈥� The solution we published in the 7 May issue (p 30) to Enigma puzzle 1639 “Square clocks” was wrong. In fact three unambiguous solutions are possible: square 16 with clocks 2, 7, 14; square 36 with clocks 6, 10, 15; square 81 with clocks 3, 6, 13. Apologies for the confusion.