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ET's expiry date
OPINION LETTERS ET’s expiry date From Bryn Glover 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. Cracoe, North Yorkshire, UK
Vacuum’s origin From Ernest Lucas 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 – 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
Enigma Number 1649
Draw conclusions BOB WALKER Joe was asked to arrange a lottery for a local charity. He made a pack of cards with one of just two numbers on each card. One could select to draw any number of cards from the pack. Prizes were awarded according to the total of the numbers on the cards drawn. Checking numbers which could be allocated prizes, Joe found that below 60 some totals were not achievable, some could be achieved in one way and some in more ways. The total of 59 could only be achieved in one way, but all higher totals could be achieved in more than one way, that is, if Joe had provided enough cards. What were the two numbers on the cards? WIN £15 will be awarded to the sender of the first correct answer opened on Wednesday 6 July. The Editor’s decision is final. Please send entries to Enigma 1649, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, or to [email protected] (please include your postal address). Answer to 1642 Triangular quartet: ENIGMA=406351 The winner Robert Brown, of Harrogate, North Yorkshire, UK Answer to 1643 Divisibility test: Largest number 9876351240, smallest number 1234897560 The winner John Reed of Maidenhead, Berkshire, UK
34 | NewScientist | 4 June 2011
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 Our Cosmic Habitat: “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. Caldicot, Monmouthshire, UK
Climbing on autopilot From Michael Lea 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. Kirkby Stephen, Cumbria, UK
The rat factor From Cedric Mims We read a great deal in New Scientist 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 riceproducing countries such as
Indonesia, Malaysia, the Philippines and other Asia-Pacific countries, show rats eat up to 15 per cent of rice produced (Rice Today, July-September 2007, p 36). 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. Griffith, ACT, Australia
War games From Stephen Kennedy 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
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. Cracoe, North Yorkshire, UK
Vacuum’s origin From Ernest Lucas 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 – 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
Enigma Number 1649
Draw conclusions BOB WALKER Joe was asked to arrange a lottery for a local charity. He made a pack of cards with one of just two numbers on each card. One could select to draw any number of cards from the pack. Prizes were awarded according to the total of the numbers on the cards drawn. Checking numbers which could be allocated prizes, Joe found that below 60 some totals were not achievable, some could be achieved in one way and some in more ways. The total of 59 could only be achieved in one way, but all higher totals could be achieved in more than one way, that is, if Joe had provided enough cards. What were the two numbers on the cards? WIN £15 will be awarded to the sender of the first correct answer opened on Wednesday 6 July. The Editor’s decision is final. Please send entries to Enigma 1649, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, or to [email protected] (please include your postal address). Answer to 1642 Triangular quartet: ENIGMA=406351 The winner Robert Brown, of Harrogate, North Yorkshire, UK Answer to 1643 Divisibility test: Largest number 9876351240, smallest number 1234897560 The winner John Reed of Maidenhead, Berkshire, UK
34 | NewScientist | 4 June 2011
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 Our Cosmic Habitat: “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. Caldicot, Monmouthshire, UK
Climbing on autopilot From Michael Lea 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. Kirkby Stephen, Cumbria, UK
The rat factor From Cedric Mims We read a great deal in New Scientist 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 riceproducing countries such as
Indonesia, Malaysia, the Philippines and other Asia-Pacific countries, show rats eat up to 15 per cent of rice produced (Rice Today, July-September 2007, p 36). 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. Griffith, ACT, Australia
War games From Stephen Kennedy 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