Microbes on Mars
Amid calls to relax the need for spacecraft sterilisation as we seek evidence of life beyond Earth (6 July, p 8), it’s worth recalling how such efforts have fared in the past.
I worked at NASA’s Langley Research Center in the 1970s, and I remember the concern that many involved in the two Viking missions to Mars had about heating sensitive components to kill microbes. In the end, Viking was a remarkable success, but worries about the impact of the sterilisation process on spacecraft instrumentation remain.
Earlier in the same decade, the Soviet Union’s Mars 2 and Mars 3 spacecraft both made it to the surface of Mars 鈥� in 1971, followed by Mars 6 in 1973. However, questions have been raised about whether their .
The good news is that the intense UV radiation encountered on Mars and strong oxidants on the surface probably killed any microbes from Earth that a Soviet 鈥� or US 鈥� mission might have deposited.
If life is found on Mars, the next big question should be: is it based on parasitism? I believe life on Earth is, which is why . Is parasitism a universal property of life or is it confined to Earth? Letting our microbes contaminate other planets may eradicate native species if they have no defence against parasites.
Our decline
You report that a new measure of global prosperity, the Genuine Progress Indicator (GPI), peaked in 1978 and has subsequently been falling while gross domestic product has continued to grow (13 July, p 14). This was about the same time that annual demand on the planet’s resources exceeded its ability to provide those resources.
It seems inevitable, therefore, that subsequent “progress” is a losing proposition. The discussion that GPI “can help policy-makers do a better job of balancing the costs and benefits of economic development” is unnecessarily complicated. Let’s just live within our (planetary) means.
You mention “the rise of neoliberalism” coinciding with the decline in GPI (p 5), but there could be many other causes. Think of the early 1970s oil crisis, for example. And whether the change was caused by one or many inputs, each would surely have had a delay before any response was seen.
Additionally, your graph shows that GPI in the UK began to decrease sharply in 1975. The rate of decrease seems to slow from 1980 and an ongoing increase began around 1990. Who came to political power in the UK in 1979 for just over a decade, and with what economic opinions?
Byfield, Northamptonshire, UK
Level the field
Some of the issues related to the US health disadvantage raised by Laudan Aron (13 July, p 28) have also been studied by Richard Wilkinson and Kate Pickett in their book The Spirit Level.
In countries and US states for which statistics exist, they found that higher income inequality leads to worse life and health outcomes across all social classes. The rich are disadvantaged as they get richer, along with the poor who get poorer. The answer is not so much to address individual issues as to create an atmosphere in which the huge inequalities, especially in the US, are reduced to levels seen in Scandinavia.
Eco energy
In your look at the rise of renewables, you said that geothermal energy is “just as effective as hydro and onshore wind, but limited to tectonically active areas” (6 July, p 6).
However, a pilot plant for a recently began producing 1 megawatt of power from water heated by forcing it through cracks in deep granite rocks warmed by natural radioactivity. Such granite domes occur in many tectonically stable places.
The predicted growth of renewables is unlikely for many reasons, including the economic slump which will make paying the large subsidies such technologies require difficult.
Also note the International Energy Agency’s main observation: the unconventional hydrocarbons revolution in the US 鈥� shale gas and oil 鈥� is changing the whole energy balance.
Haywards Heath, West Sussex, UK
Suicide bombers
Rebranding terrorist “martyrs” as suicidal individuals as suggested by Adam Lankford is long overdue (6 July, p 24). The use of words such as “war” and “terrorism” give them great kudos.
There have been a number of studies into the impact of Israeli policies on the mental health of Palestinians: of military operations, of the disorganisation of life caused by checkpoints, house demolitions and so on. But Lankford sees only the depression, he doesn’t address its causes.
He cites the West Bank barrier as the one strategy against suicide bombers that can be called a success. This legitimises the further oppression of Palestinians by the very state whose policies have generated resistance, including suicide bombing, and which damage psychological well-being.
Cool sunrise
Articles on artificial day and night helping to maintain the quality of picked vegetables (29 June, p 17) and UV light keeping fruit mould-free (15 June, p 23) set me thinking. Domestic fridges could be fitted with LEDs of the right wavelength to maintain circadian rhythm, and a UV light in a fridge drawer could keep fruits mould-free.
You can't miss
We have had the fly-in-the-urinal “nudge” (22 June, p 32) and the historic use of a bee (13 July, p 33) to influence men’s aim for the better. In Slovenia I discovered a urinal with a tiny set of soccer goalposts and a ball suspended by a thread from the crossbar 鈥� irresistible!
Does this count as a nudge? A bar in Berlin has a sign proclaiming that “the man who picks the fag-ends out of the urinals also puts the ice in the drinks”.
Why frack?
Fracking technology has developed effective and accurate horizontal drilling to exploit fossil fuels deep underground (8 June, p 7). This is precisely the technology that would allow the exploitation of clean, sustainable geothermal energy. There is an almost unlimited supply of this in many places; why not develop it?
Big questions
In his letter, Stephen Rowe is right to say that we need to understand gravity better rather than invent dark energy to account for the accelerating expansion of the universe (15 June, p 33).
We know that quantum theory is accurate over atomic scales. The assumption that gravitational forces are the same at intergalactic scales as they are within our solar system is equivalent to assuming that quantum theory gives a good description of the behaviour of rice grains and snooker balls. Clearly it doesn’t, and maybe gravity has a similar limitation of scale.
Perpetual motion
Regarding the health costs of excessive sitting (29 June, p 44), what’s this obsession with living as if there will be no end? If I spend all my time moving, as suggested, will I also find time to create something of lasting value?
Shakespeare’s sonnet number 74 says it all: “But be contented when that fell arrest / Without all bail shall carry me away, / My life hath in this line some interest, / Which for memorial still with thee shall stay.”
From Tim Jackson
Using the figures in your article, I estimate that my decades-long subscription to 快猫短视频 has shortened my life by about a month. Perhaps you should put a health warning on the cover.
Rossendale, Lancashire, UK
One man's comma鈥�
Hugh Lawton and Marc Smith-Evans may unwittingly be indulging in cultural imperialism when talking about download progress figures of “4,100%” and “9,800%” for MacKeeper software (Feedback, 22 June). Where someone in the UK or US sees a thousands separator, a few hundred million in mainland Europe see a decimal point.
Ancient mystery
You mention the possibility that five other hominins co-existed in Africa at the same time as Homo habilis, each with different human-like features (13 July, p 34).
Is it also possible these hominins were close enough to interbreed and produce fertile offspring, leading to a number of them being our ancestors, rather than just one?
Fact and fiction
Your readers might enjoy knowing that the Rashomon software, which syncs video of street protests from multiple sources (29 June, p 22), is almost certainly named after a 1950 Japanese cinematic masterpiece by director Akira Kurosawa.
According to Christoph Koettl of Amnesty International, the software will produce a “comprehensive view” of a situation that “could be very, very helpful in our investigations”.
In a comparable manner, Kurosawa’s Rashomon retells the story of a crime by stitching together different accounts.
For the record
鈥� We got nuclear geophysicist Rob de Meijer’s academic affiliation wrong in our look at a new theory of how the moon formed (6 July, p 30). His correct place of work is the University of the Western Cape in Bellville, South Africa
鈥� It’s not the end of the world, but Feedback really should have referred to the last book of the Bible as Revelation (13 July)