Accidental origins
I found myself much less surprised than Bob Holmes that species can arise rapidly or even suddenly (13 March, p 30). The botanist Irene Manton and her students in the middle of the last century clarified the ancestry of several groups of British ferns, and showed just how easily a new species can emerge.
Britain has three Polypodium fern species that do not often interbreed. The hybrid of diploid P. cambricum and tetraploid P. vulgare is usually a sterile triploid, but occasionally it becomes fertile after chromosome doubling. The offspring, the hexaploid species P. interjectum, is morphologically and ecologically distinct. It can backcross with either parent, but the product is a conventionally sterile hybrid. This is speciation in action and is probably happening all the time.
Consider another case: the British whitebeam shrubs (Sorbus species) show rapid speciation and evolution progressing in real time on cliffs in the Avon gorge, on the Devon coast and on the Isle of Arran.
Creationists demand to be shown macroevolution in action. These are just two examples.
From Michael Crick
Could catastrophe theory explain the apparently random distribution of speciation events as sudden effects of fairly continuously varying causes? My concern would be whether the mathematics involved could handle the number of “dimensions” involved, but it should be possible to set up a simplified model to see whether its predicted distributions correspond to observation.
Hexham, Northumberland, UK
Hotel microbia
So the microbial flora that cloaks, occupies and infiltrates us also communicates with us (6 March, p 36). Do we need to rethink our place in the scheme of things? We are constructed of eukaryotic cells that function through an assemblage of organelles 鈥� nucleus, nucleolus, mitochondria, Golgi apparatus and so on 鈥� many if not most of which are believed to derive from the incorporation of free-living microbial predecessors into the evolving cell. Furthermore, human cells are outnumbered 10 to 1 in our own bodies by microbial cells.
How many of us are ready to face up to the fact that we may operate primarily to serve as ambulatory refectories for our microbial inhabitants?
A place near the sun
I am glad to see that Solar Orbiter, which would go unprecedentedly close to the sun, is on the European Space Agency’s list of three missions being considered for two launch slots (27 February, p 7). From its unique vantage point, high out of the plane of Earth’s orbit, the craft would be guaranteed to make high-resolution solar images and measure the solar wind. It should allow us to see where the solar wind streams come from.
In contrast, to a solar astronomer like me, PLATO (Planetary Transits and Oscillations of Stars) is a relatively minor variation on the current Kepler mission, and the Euclid mission to search for dark matter by surveying galaxies and clusters of galaxies is a long shot in terms of actually achieving its goal. I hope that Solar Orbiter gets a slot.
ET gone in a flash
Why have we never found evidence of aliens (27 February, p 46)? The most obvious explanation is that civilisations capable of advertising their existence across the universe have very short durations.
Ours only started inadvertently advertising its presence by radio broadcasts in the last century. Since then we have narrowly avoided extinction by nuclear war and now appear to be well on the way to rendering Earth uninhabitable by changing the composition of its atmosphere.
Other civilisations may take very different forms, but the evolutionary pressures are likely to be similar everywhere: a certain level of technology is followed by exponential growth of population and resource use 鈥� pressures which lead inevitably to catastrophe by one means or another.
Blink, and you missed us.
From Clive Page
Ray Francis is unduly pessimistic in saying that the inverse square law renders the chances of aliens detecting our radio signals negligible (6 March, p 24). Signals from the 23-watt transmitter on Voyager 1, on the edge of our solar system, have been picked up by radio amateurs in Germany using a dish of medium size. Proxima Centauri is about 2400 times further away, so around 130 megawatts would be needed to give the same received signal strength on Earth.
Luton, Bedfordshire, UK
From Leslie Martin
We are becoming more efficient with our broadcasts: line-of-sight transmission and satellite downlinks waste less energy into space. Any civilisation that does the same will appear dark to the sky, apart from a few decades during the development stages.
Greenford, Middlesex, UK
From Henry Harris
I am a retired NASA scientist who headed a project for creating the technology needed to reach a nearby star. If it turns out, as physicists such as Paul Davies are insisting, that the universe has more dimensions than just four, perhaps there might also be short cuts that circumvent the speed of light using sufficiently advanced technology.
My interstellar project proved that travel to a nearby star is possible, within current physics, if we are willing to invest the resources. If it is possible today, who is to say it might not be practical tomorrow?
Pasadena, California, US
Coral clouded
Graham Jones worries that at sea temperatures greater than 26 掳C coral ceases to release dimethyl sulphide (DMS) (27 February, p 17). Since DMS aids in the formation of clouds, Jones postulates that a reduction could dry out the north Queensland rainforests.
The majority of rainfall over north Queensland is in the summer monsoon, when sea surface temperatures off the coast of this region are in the range of 29 to 30 掳C. It would appear that Jones overestimates the effect of DMS on cloud and rainfall on the north Queensland rainforest.
The editor writes:
鈥� Jones says that in winter, south-easterly trade winds may carry the DMS aerosol particles into rainforests, producing rain, and suspects that the lack of this could dry them. More research is, as he says, required.
Eyes ablaze
There is a very practical application of knowing that decision-makers can be identified by their wide eyes (6 March, p 11). I used to work as a consultant psychiatrist in prisons and special psychiatric hospitals, and I noted that before a threatened or actual assault my patients’ pupils would dilate. I attributed this to the fight-or-flight reaction. It also applied to psychotic patients who were impulsively and therefore more unpredictably aggressive.
Rather than moving away, I found it better to stand shoulder-to-shoulder 鈥� a very supportive stance and not threatening.
A word of warning, though, if you are ever in this situation: in some circles it is common practice in a fight to hit an opponent with a sideways jerk of the head 鈥� so allow a little separation.
Inheriting atheism
In their article asking where atheists come from, Lois Lee and Stephen Bullivant suggest that a lack of belief is worthy of inquiry (6 March, p 26). I come from a line of atheists. Our family could no more suddenly discover a need for an almighty than abandon deeply held beliefs like justice and equality before the law, hard work and socialism, which we acquired during our upbringing.
Conceivably, childhood beliefs that can be challenged by logic might be shaken in adult life and by education, but beliefs that are supported by it 鈥� surely not.
From Hugh Roddis
Everyone is a mixture of physical and mental heritage: genes and memes. Passing on the vast mass of information between generations requires belief 鈥� it is impossible to personally test everything we learn. Like genes, memes do not need to be “right” to succeed; just to confer an advantage or be neutral.
As to a link between education and atheism: in the 18th century, critical thinking was a major part of education. Today in many fields, even at graduate level, education is simply data transmission, and critical thinking is ignored or actively discouraged. Is anyone looking at links between atheism and field of study?
Falmouth, Nova Scotia, Canada
From Tony Graham
There are two sorts of religion, as different from each other as science and alchemy. A faith that starts by liberating people can be hijacked. That happened to Christianity in 312 when the would-be Roman emperor Constantine kidnapped God to support his bid for power.
Belief became a matter of believing unprovable things before breakfast, and God’s main desire henceforth was not that we should do justice but that we should tell him often how marvellous He is.
I’d have given it all up, but I was fortunate enough to go to the ecumenical liberation theology centre in Jerusalem and meet Christians, Jews and Muslims who are working together for peace and justice. I suggest that what Martin Luther King called the moral universe, and the people who give their lives to healing it, are fit subjects for objective study alongside the material universe.
Crawley, West Sussex, UK
From Ivor Watts
As the philosopher Immanuel Kant points out in Critique of Pure Reason, we may dismiss such propositions as “God exists” as uninformative: “existence is not a predicate” as logicians would say.The implication is that the set of all things that are not a part of god is empty: that is, pantheism.
Tiverton, Devon, UK
For the record
鈥� Green chemist Jim Hutchison is at the , not Oregon State University as we said (13 March, p 34).
鈥� We said alkali-vapour lasers have “mass-to-power ratios that far exceed other lasers”; we meant “power-to-mass” (27 February, p 22).
鈥� We referred to “Antonie Leeuwenhoek” as “father of the microscope” (27 February, p 36). His family name was van Leeuwenhoek; our dictionary calls him Antoni, though many other spellings are also in use.