Odds-on result
When I read the assertion by Pat Michaels that predictions based on new climate research “should have an equal probability of being better or worse” for Earth’s climate (4 November, p 18), I dropped my copy of New 杏吧原创 in horror. Is Michaels really saying that we should always expect the balance of new scientific research to fall in line with currently accepted predictions, and that there must be something wrong with the science if it suggests we should change the way we think about something?
Reflecting on this logic, I am actually in favour of it. I gave up smoking on the basis that “scientific research” carried out in the 20th century showed that it was far more harmful than originally thought. Now I understand that those results must be biased by the anti-smoking lobby: we should have seen just as much evidence telling us that we should smoke more as telling us that we should stop. Thanks to Michaels I can now safely light up in the knowledge that any serious health problems I suffer in the future will be entirely unrelated to my smoking.
Vanishing analysts
Your article on food fraud made interesting reading, but its contents did not come as news to the UK’s few remaining public analysts (11 November, p 40). We are appointed under statute to direct the analysis of food to help local authorities enforce food law, and have been protecting the public from adulterated food for nearly 150 years.
The article highlighted several high-profile special initiatives, but routine sampling 鈥� to detect the watering of milk or high levels of fat in mince, for example 鈥� is in terminal decline. Imagine a town with a population of 300,000 and the number of different food products that those people eat at home, at work and at play in a day. On average only one of those foods will have been sampled for a public analyst to test for safety, nutritional content or authenticity. For every 拢100 spent on food by consumers, less than one penny is spent by local authorities on testing.
Armchair blowback
You report that the US Department of Defense is looking to robotics to reduce troop losses on its side (28 October, p 24). One contractor says “we are trying… to create a very un-level battlefield”. This commitment to one form of asymmetric warfare can have only one outcome: it will encourage the adversary to embrace two other forms 鈥� guerrilla warfare and terrorism.
Home-schooling truths
There are other, perhaps more convincing ways of reading the data on home-schooling (11 November, p 20). It is certainly becoming more popular, but the conventional wisdom among home-schoolers 鈥� borne out by the available data 鈥� is that the number of evangelical and fundamentalist Christians in the home-school population has already peaked, and that the increasing total reflects the growing acceptance of home-schooling among other groups.
As a Christian (Catholic) home-schooler, one of the greatest blessings of avoiding our local public school in Texas is that we can teach our children real science from real texts (we use good introductory college texts as an alternative to the wretchedly muddled public high school texts) without pressure to hush up inconvenient truths about biology, geology and astronomy.
Arguably, others will benefit from the home-schooling of children of creationist families. Many school districts 鈥� notably the one in Texas where I was taught 鈥� used to have constant battles over science classes, featuring school board takeovers and anxious teachers hesitant to teach anything at all about the origin of species. The availability of home-schooling and of private Christian schools reduces the pressure on public school districts to shape science teaching to accommodate creationist beliefs.
There is no meaningful way that state regulation could address the teaching of creationism by home-schoolers. A better solution is that chosen by the University of California system, which refuses to recognise science classes that teach certain creationist curricula. This avoids unfairly and uselessly burdening home-schooling families, and has the advantage of being enforceable.
From Elizabeth Ross
You have previously reported on the poor science education that the American public school system provides, stating that unsatisfactory science programmes continue due to a lack of national standards and the notoriously low standards established by the No Child Left Behind Act (19 August, p 11). Parents informed by this article and similar ones may choose to fill those potential gaps in their children’s education through home-schooling.
Cary, North Carolina, US
From Norman Klein
I read your special report with glee. The home-schooling movement may well be Galapagos-in-reverse: separate home-schooled creationists from the general population then release them into the modern world, where survival of the fittest will ensure they die out.
Westport, Connecticut, US
Shot down in flames
Sue Russell paints a grim picture of some fire investigators’ interpretive practices (4 November, p 42). These were prevalent years ago and may still exist in some outposts, but in the UK current procedures are far removed from the archaic methodology described.
The professional standards of fire investigators in the UK have developed greatly over the past 30 years. Trained practitioners no longer (if they ever did) base their findings on myths and legends, but on a good understanding of fire science. British police forces, fire authorities and forensic science laboratories now ensure that their fire investigators receive specialist training in the theory and practice of fire scene examination.
There are instances where the cause of a fire cannot be determined with absolute certainty, but the likelihood in the UK of an accidental fire being misinterpreted as deliberate is now extremely remote.
Patient-group funding
You state that Neuronetics gave between $10,000 and $150,000 to the Depression Bipolar Support Alliance in 2005 (28 October, p 18). We feel it is important to clarify that the total funds provided to DBSA in 2005 from Neuronetics were $26,000. DBSA and other third-party organisations are key sources of information and support for patients with depression. We respond to their requests for grant support to help them achieve their mission.
Friendly fever
You report that researchers at the Roswell Park Cancer Institute have “replicated the effects of a fever in mice by keeping them at 39.5 掳C” and have observed a positive effect on their immune systems (11 November, p 17). This could be a clue to the cases, documented many years ago, of remission of cancers in patients who happened to contract infectious diseases and became febrile.
However, raising the temperature of a mouse or a human by external means is not the same as fever. In a fever, the set point of the thermoregulatory system is changed so the body raises itself to a higher temperature. Often a febrile human patient feels cold and shivers.
With external heating, by contrast, the thermoregulatory system struggles to resist the rise in temperature. The consequent stress has been one of the main reasons for the limited use, and limited success, of this approach to treating cancers. A drug that raised the set point, to a controllable extent, could be very useful.
Monstrous logic
You report Leslie No猫 of the Sedgwick Museum in Cambridge, UK, as saying that the osteology of the plesiosaur’s neck shows that it is only flexible downwards (4 November, p 17). You conclude that this rules it out as a Loch Ness monster, which reputedly raises its head swan-like from the water. No猫 has evidently overlooked the possibility that plesiosaurs, when on the surface, might swim on their backs.
Trekker maths
Feedback puzzles over why the WWF estimates that “only 20 pence of every 拢2 spent by an average trekker each day reaches village economies” (4 November). Why not say 10 per cent? But if you replace the word “every” with “the” it all makes sense. Trekkers spend on average 拢2 a day, so only 20 pence goes to the locals.
Hair today
Hair does a lot more than simply signal social status or dexterity (4 November, p 39). In men it is a very clear marker of age. But what does this mean in evolutionary terms?
I suspect that lice could tell us a lot about when we lost our fur and when we started wearing clothes.
The head lice that infest children are different from the body lice that carry typhus and different again from pubic lice. Surely their genetics could be examined and their evolutionary splitting points pinned down.
Presumably head lice split from body lice when the fur went, and body lice split from pubic lice when clothes provided a nice new environment.
From Noel Hodson
Another possible benefit to early humans of waist-length head hair may have been to make the wearer seem much larger, particularly when under threat. Head hair can “stand on end” and many tribes have cultivated Big Hair. The busby hats worn by the guards at Buckingham Palace in London aim for the same effect.
Good science demands that 50 hairy, somnolent students be frightened witless to study this phenomenon.
Oxford, UK
For the record
鈥� Leuven is in Belgium, not the Netherlands as stated in the story on bee police (4 November, p 16).
鈥� Andrew Mackie is not employed by the British government (11 November, p 40). He is a public analyst for Edinburgh City Council.
鈥� Duchenne muscular dystrophy is 10 times as common as stated in our article on a potential stem-cell treatment for the condition (18 November, p 12). Around 1 in 3500 children are affected by MD.
鈥� In the item on the discovery of a natural painkiller (18 November, p 21), both figures quoted in grams per kilogram of body weight were in fact milligrams per kilogram of body weight.
鈥� Myron Ebell is director of energy and global warming policy at the Competitive Enterprise Institute, Washington DC. Contrary to what we stated in our climate change special report (4 November, p 18), he has never been a climate negotiator for George W. Bush’s administration.
Hair today
Adrian Barnett’s article shows, once again, the brilliance of sci-fi writer Douglas Adams, who in The Hitchhiker’s Guide to the Galaxy had us all descended from hairdressers, cast out from the planet Golgafrincham.
Ethics and extinction
It is good to see a demand for an ethical dimension to climate talks (11 November, p 8). Clearly in human terms many of the societies that are likely to be most disadvantaged by global warming are among those who have had the lowest emissions.
We still appear, however, to be locked into an excessively anthropocentric view of climate change. It does not threaten our species with extinction. Many others are threatened, most obviously through direct impacts, such as that on polar bears, but also as a result of human refugees overwhelming habitats that have hitherto suffered relatively little human encroachment.
Clearly any ethical debate needs to consider what, if any, right we have to further threaten the existence of other species.
Non-accidental adjacency
That volume 6 of The Australian Encyclopaedia was labelled “Marsupials to Parliament” was probably not a matter of chance (Feedback, 28 October). The editor-in-chief of the 1958 edition, Alec H. Chisholm, was a family friend and told me he took a certain delight in so labelling that volume.
“Marsupials to Parliament” has 492 pages and the last entry is “Parliament Houses”. Volume 7, “Parliamentary to Sandal Box” runs to 552 pages. The first entry, “Parliamentary Government”, takes up 20 pages, followed by “Parliamentary Salaries” (2 pages), before moving on to “Paroo River”. It would have seemed reasonable to have put “Parliamentary Government” and “Parliamentary Salaries” with “Parliament Houses” in volume 6, making it 514 pages, and reducing volume 7 to 530 pages.
I surmise that “Chissy”, as my mother always called him, deliberately ended volume 6 that way to get his “Marsupials to Parliament” title. My wife’s comment: “Unkind to marsupials!”
No paradox in black holes
I believe Leonard Susskind’s approach to black holes to be wrong, and that he is trying to invoke quantum mechanics to resolve a paradox that is not there (28 October, p 36).
If you derive contradictory statements in a theory, you have a paradox. This is not solved by stating that the two contradictory statements are both true at the same time. A paradox is usually the result of starting with a wrong assumption. It can be resolved by identifying and correcting that wrong assumption.
Let us insist that there is only one course of events for an object falling into the black hole. If we insist that what an outside observer of a black hole observes is what actually happens, the paradox can be resolved, although we would have to sacrifice the traditional image of what a black hole is.
From the outside observer’s point of view, it seems that an object falling into the black hole never reaches the event horizon. Instead, it is eventually blasted to pieces by the radiation of the black hole and its information content is radiated into space. Let us just insist that this is what the inside observer also sees.
If we calculate how long it takes for the object to reach the event horizon and finally the centre of the black hole, we find that this takes only a very short time 鈥� say n seconds to reach the event horizon and m seconds to reach the centre. This seems to contradict what the outside observer sees.
What is wrong in this calculation is the assumption that the black hole is a static entity which exists for a very long time. Instead, it is a very dynamic and violent environment and evolving extremely quickly. Its inside is the still-evolving gravitational collapse, and this takes only a very short time.
Consider a particle being sent into the black hole straight towards the centre. The deeper it goes in, the more slowly time proceeds in the outside observer’s frame of reference, so it seems to freeze in time and nearly stop just above the event horizon. This would even happen to a photon moving in at the speed of light.
Now, over a very long time (from the outside observer’s point of view), the black hole radiates information and energy away, and the event horizon shrinks. The photon can now go further in while the event horizon shrinks in front of it. It moves nearly in lockstep with the event horizon, slowly approaching it but never reaching it, no matter how long the observation takes. Since the photon is actually moving at the speed of light, this means that from the point of view of an observer near the event horizon, the event horizon shrinks very quickly at almost the speed of light. For any object falling into the black hole, the event horizon would shrink quickly in front of it and the speed of this shrinking would increase the deeper you fall in, approaching the speed of light as you get closer to the event horizon. At the same time, the temperature and radiation would become ever more intense.
So before the time n to reach the event horizon has passed, the event horizon is no longer there. So the “time-freezing effect” in the black hole means that the time between the formation of the black hole and the end of its evaporation is very short for an observer inside the black hole. Only from the outside does the black hole appear as a static object. Any calculation showing that it takes only n seconds for you to fall through the event horizon is meaningless because the event horizon simply does not sit and wait there for you.
If we accept all this, the description of the outside observer is completely consistent with the description of the inside observer. Nothing that falls into a black hole will ever reach the event horizon, so there is no information paradox. This is also true for the matter of the original star that formed the black hole. There is no singularity inside and, in fact, there is no inside.
As long as the black hole exists, the event horizon is always in the future of anything that falls inside. The moment anything reaches the event horizon is the moment when the black hole finishes evaporating and the event horizon disappears. So a trajectory into the black hole just comes out on the other side after what is a short time for an object following that trajectory (if your wavelength is longer, you might come out a little bit earlier).
For an outside observer, this would be in a very distant future. Therefore, it is wrong to think of the event horizon as a sphere in present space-time (surrounding a singularity) moving through time. Inside the black hole the “world lines” that describe the trajectory of an object through Einsteinian space-time are very short. Near the event horizon, only a very short time passes between the creation and the end of the evaporation of the black hole. What is behind the event horizon is not a singularity but the empty space of a very distant future (or a very near one, if you take the route through the black hole).
The event horizon shrinks for the inside observer even if it expands from the outside observer’s view when more matter falls into the black hole (for example when the matter of the original star rushes inwards). The expansion observed outside is due to the contraction of space in the direction of the black hole. From the outside point of view, space near the event horizon is flattened into thin layers and the central region or point of the black hole seems expanded into a sphere. When a star collapses to form a black hole, the event horizon will start to expand from its centre when space in that direction is contracted. For an outside observer, the central point appears “blown up”. Practically no time will pass at that central point from the moment of the black hole’s formation to the end of its evaporation. So the event horizon that is always in the future can be thought of as the “blown-up” image of that particular point in space-time when and where the black hole finishes its evaporation. The further out you are, the more time passes.
Greed on the high seas
You rightly condemn the failure of the European Union to introduce realistic cod fishing quotas (11 November, p 3). Unfortunately, the greed of European fishing companies and the failure of EU states to control their activities on the high seas are now having an impact on fisheries in the southern hemisphere.
I write having just emerged from a five-day meeting in Hobart, Tasmania, attended by 24 nations and an EU delegation. Its central aim was to establish a South Pacific Regional Fisheries Management Organisation to control currently unregulated fishing in international waters.
Attempts to introduce interim management measures such as capping fishing effort at current levels and preventing bottom trawling in sensitive habitats were vigorously resisted by the EU delegation and consensus was not reached. The EU agenda annoyed and frustrated other nations, particularly coastal and island states. EU “supertrawler/seiners”, each 150 metres long and with a 20,000-tonne hold capacity, continue to plunder South Pacific mackerel stocks.
It is certainly time for EU fisheries ministers to act in a responsible manner, but don’t hold your breath.