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Mars risk
OPINION LETTERS Last? Not so fast From Jules May The proposal to build a universal programming tool entirely out of questions is not a new one. (8 June, p 36). In fact it has a long and sorry history. For example, in the early 1980s there was a system called TLO, which promised to construct business software by asking questions of the user. TLO stood for The Last One – in other words, the last program anyone would ever need to buy. Needless to say, the software industry survived this challenge. There have been others, and there will be more, yet none will succeed. Why? Because their proponents misunderstand the nature of the task. Programmers are, by nature and necessity, pioneers. We rarely have to solve the same problem twice. The reason why software is a shambles – and, to be fair, it’s hard to disagree with that description – is because we’re constantly exploring the unknown and recently illuminated parts of the problem space.
The missteps are just part of the territory. Most software defects today are design errors born of such uncertainty, rather than grammatical problems in the code. Montrose, Angus, UK
Mars risk From Nigel Henbest You report that radiation levels would be too high for a trip to Mars and back (8 June, p 17). When I researched my book Mars: The inside story in 2000, I was told the radiation level for a one-year round trip would be similar to that experienced by firefighters at the Chernobyl nuclear plant after its meltdown – far too risky. But the results from the Radiation Assessment Detector on the Mars rover Curiosity – the basis of your story – show levels are much lower. NASA’s current lifetime radiation limits for astronauts equate to raising the chance of dying from cancer by 3 per cent; the new results suggest a return trip to Mars would expose astronauts to a risk of less
Enigma Number 1754
Elementary SUSAN DENHAM My textbook lists the two-letter symbols for chemical elements, including both old and new abbreviations for some of them, as: Ac Ag Al Am Ar As At Au Ba Be Bh Bi Bk Br Ca Cd Ce Cf Cl Cm Co Cr Cs Cu Db Ds Dy Er Es Eu Fe Fm Fr Ga Gd Ge Ha He Hf Hg Ho Hs In Ir Kr La Li Lr Lu Lw Md Mg Mn Mo Mt Na Nb Nd Ne Ni
No Np Os Pa Pb Pd Pm Po Pr Pt Pu Ra Rb Re Rf Rg Rh Rn Ru Sb Sc Se Sg Si Sm Sn Sr Ta Tb Tc Te Th Ti Tl Tm Xe Yb Zn Zr. Using letters no more than once, I have written as many as possible around a circle such that, if you look at any adjacent pair of letters, then reading them clockwise they are one of the above elements. How many letters have I written?
WIN £15 will be awarded to the sender of the first correct answer opened on Wednesday 17 July. The Editor’s decision is final. Please send entries to Enigma 1754, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, or to [email protected] (please include your postal address). Answer to 1748 Quo Vadis?: The numbers on the cards in the bottom row of the grid are 1, 3, 2 and 1. The winner Trevor Morley of Weiterstadt, Germany
30 | NewScientist | 22 June 2013
than 4 per cent, while a one-way trip would correspond to only a 2 per cent increase – actually below NASA’s danger level. Considering all the other risks involved in a flight to Mars, radiation is likely to be the least of their worries! Loosley Row, Berkshire, UK From Brian Horton Unless humans have changed dramatically in recent centuries, when risky exploration of regions
“could fulfil our needs without generating any greenhouse gases”. But nuclear contributed only about 13 per cent of global electrical energy in 2011 – equivalent to maybe 5 per cent of total energy consumption. Not only would nuclear have to expand vastly, but we would need to find ways to turn its electricity into fuel for transport. Neither batteries nor hydrogen can hope to meet this requirement. Ely, Cambridgeshire, UK
Just a side effect
such as the Arctic attracted plenty of volunteers, I expect there will be no shortage of people willing to spend 12 months or more on a high-risk trip to the Red Planet. West Launceston, Tasmania, Australia
Nuclear costs From Robbie Morrison Further to your Instant Expert on nuclear energy (1 June). The costs of civil nuclear power have shifted from the early hope of “too cheap to meter” to too costly to mention. And the graph summarising new nuclear plants in the pipeline also looks fanciful. For example, Hinkley Point C in the UK does not meet the criteria for “approvals, funding in place. Expected generation in 8 to 10 years.” Berlin, Germany From Clive Semmens Congratulations on your wellbalanced articles on nuclear energy. You played up the possibility that nuclear energy
From Norman Bacrac On the possible evolutionary advantage of consciousness (18 May, p 38), three ideas were offered: it allows us to “chunk” information to assist with problem-solving; to understand other people’s minds; and as a requirement to reflect on experiences before we can talk about them. But all these processes are presumably associated with activity in the brain that would be detectable by modern means. If this were not the case, we would relapse into Cartesian dualism, implying a suspension of brain activity while the conscious agent is working its magic. The inevitable conclusion has to be that, yes, for good or ill, consciousness does accompany higher mental functions of the sort described, but as an inert secondary phenomenon, not as their driver. Let’s admit it: there is no actual biological necessity for the existence of consciousness. London, UK
No let up From Charlie Nelson There are two dangerous consequences that follow from the study suggesting the world will warm more slowly than we thought (25 May, p 8). The first is that politicians will use this to
The missteps are just part of the territory. Most software defects today are design errors born of such uncertainty, rather than grammatical problems in the code. Montrose, Angus, UK
Mars risk From Nigel Henbest You report that radiation levels would be too high for a trip to Mars and back (8 June, p 17). When I researched my book Mars: The inside story in 2000, I was told the radiation level for a one-year round trip would be similar to that experienced by firefighters at the Chernobyl nuclear plant after its meltdown – far too risky. But the results from the Radiation Assessment Detector on the Mars rover Curiosity – the basis of your story – show levels are much lower. NASA’s current lifetime radiation limits for astronauts equate to raising the chance of dying from cancer by 3 per cent; the new results suggest a return trip to Mars would expose astronauts to a risk of less
Enigma Number 1754
Elementary SUSAN DENHAM My textbook lists the two-letter symbols for chemical elements, including both old and new abbreviations for some of them, as: Ac Ag Al Am Ar As At Au Ba Be Bh Bi Bk Br Ca Cd Ce Cf Cl Cm Co Cr Cs Cu Db Ds Dy Er Es Eu Fe Fm Fr Ga Gd Ge Ha He Hf Hg Ho Hs In Ir Kr La Li Lr Lu Lw Md Mg Mn Mo Mt Na Nb Nd Ne Ni
No Np Os Pa Pb Pd Pm Po Pr Pt Pu Ra Rb Re Rf Rg Rh Rn Ru Sb Sc Se Sg Si Sm Sn Sr Ta Tb Tc Te Th Ti Tl Tm Xe Yb Zn Zr. Using letters no more than once, I have written as many as possible around a circle such that, if you look at any adjacent pair of letters, then reading them clockwise they are one of the above elements. How many letters have I written?
WIN £15 will be awarded to the sender of the first correct answer opened on Wednesday 17 July. The Editor’s decision is final. Please send entries to Enigma 1754, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, or to [email protected] (please include your postal address). Answer to 1748 Quo Vadis?: The numbers on the cards in the bottom row of the grid are 1, 3, 2 and 1. The winner Trevor Morley of Weiterstadt, Germany
30 | NewScientist | 22 June 2013
than 4 per cent, while a one-way trip would correspond to only a 2 per cent increase – actually below NASA’s danger level. Considering all the other risks involved in a flight to Mars, radiation is likely to be the least of their worries! Loosley Row, Berkshire, UK From Brian Horton Unless humans have changed dramatically in recent centuries, when risky exploration of regions
“could fulfil our needs without generating any greenhouse gases”. But nuclear contributed only about 13 per cent of global electrical energy in 2011 – equivalent to maybe 5 per cent of total energy consumption. Not only would nuclear have to expand vastly, but we would need to find ways to turn its electricity into fuel for transport. Neither batteries nor hydrogen can hope to meet this requirement. Ely, Cambridgeshire, UK
Just a side effect
such as the Arctic attracted plenty of volunteers, I expect there will be no shortage of people willing to spend 12 months or more on a high-risk trip to the Red Planet. West Launceston, Tasmania, Australia
Nuclear costs From Robbie Morrison Further to your Instant Expert on nuclear energy (1 June). The costs of civil nuclear power have shifted from the early hope of “too cheap to meter” to too costly to mention. And the graph summarising new nuclear plants in the pipeline also looks fanciful. For example, Hinkley Point C in the UK does not meet the criteria for “approvals, funding in place. Expected generation in 8 to 10 years.” Berlin, Germany From Clive Semmens Congratulations on your wellbalanced articles on nuclear energy. You played up the possibility that nuclear energy
From Norman Bacrac On the possible evolutionary advantage of consciousness (18 May, p 38), three ideas were offered: it allows us to “chunk” information to assist with problem-solving; to understand other people’s minds; and as a requirement to reflect on experiences before we can talk about them. But all these processes are presumably associated with activity in the brain that would be detectable by modern means. If this were not the case, we would relapse into Cartesian dualism, implying a suspension of brain activity while the conscious agent is working its magic. The inevitable conclusion has to be that, yes, for good or ill, consciousness does accompany higher mental functions of the sort described, but as an inert secondary phenomenon, not as their driver. Let’s admit it: there is no actual biological necessity for the existence of consciousness. London, UK
No let up From Charlie Nelson There are two dangerous consequences that follow from the study suggesting the world will warm more slowly than we thought (25 May, p 8). The first is that politicians will use this to