Letter
Life as we know it needs the Universe to be just the way it is, but does the
Universe need life? I very much doubt it.
Letter
I have been collecting CDs to make a lamp. If you stack the discs on top of
each other and view them from the side, you will notice that light passes
through the block.
I used the florescent strip from a camping lantern and passed the tube
through the holes on the CDs. Add a base and top to house the contacts and
batteries/transformer, and bingo, your lamp.
Black holes
Mark Ward’s review of The Chinese Space Programme
(“It’s a blast”, 6 June, p 54)
was most welcome. But his concluding remark that the book has “far
too much information” struck me as curious鈥攕uch works become invaluable in
reference collections. Another reference book might have reminded him that
Republican Senator Joseph McCarthy was the 1950s witch-hunter; Eugene, a decade
later, was one of Robert Kennedy’s rivals for the Democratic presidential nomination.
Cloud cover
I am grateful for the publicity that New 杏吧原创 has given to my
paper with Tim Lenton on biogenic cumulus clouds
(“Send in the clouds”, 30 May, p 28).
But Lynn Hunt’s article puts an unjustified slant on our ideas in relation to Gaia.
The natural selection mechanism we suggest could, it is true, be a component
of a thermostat, but no one has yet shown how the thermostat could be adjusted
appropriately. Indeed, it is not even clear if this thermostat is wired the
right way: it could “click” on and stay on until the world freezes for all that
our study shows. It may be that a thermostat is there but the evolutionary (or
other) process leading to it needs to be explained.
In the paper we emphasised the current lack of principles to explain the
evolution of life-like properties in a single system that does not replicate
itself. We cite the critiques of Gaia on these lines by Ken Caldeira and by
Richard Dawkins, and also mention the general ineffectiveness of Neo-Darwinian
processes for global adaptation. Today complexity theory is often invoked as a
route to adaptation that is not based upon natural selection. It has, however,
yet to show how any adaptation can arise at all.
For those who find the evidence for homeostasis of the planet compelling,
this leaves several options. The gloomiest of these is the anthropic principle:
here the homeostasis is counterfeit鈥攚e happen to have survived this far
but there is no guarantee that life on the planet will not destroy itself. A
second is panspermia, the idea that space is full of spores, that stable
planetary systems have contributed more of them than have unstable ones, and
that newly colonised planets are thus receiving ever more stabilising mixes of
colonists. This brings in natural selection and thus hope, but it is
theoretically dubious and is unsupported by data. Thirdly, there is the
possibility that there is a selection process inherent in community assembly
which has yet to be described.
For the time being, however, it seems best to assume that the planet is
subject to a set of out-of-control thermostats, and that human rationality, via
science, is its main hope for homeostasis.
Reef madness
While the research into trawling in Australia
(“Watery wastelands, May 16, p 40)
may be advanced, the decisions taken as a result of that research have been
extremely poor. Even in the Great Barrier Reef Marine Park and World Heritage
Area, trawling continues its unabated destruction of the seafloor environment
and of the numerous “bycatch” species.
At present, almost 80 per cent of the Great Barrier Reef is open to trawling.
Less than 5 per cent of the Reef is fully protected from exploitative
activities. Turtle excluder devices are still not mandatory in Queensland
waters, despite the fact that more than half of the recorded loggerhead deaths
this year were the result of drowning in trawl nets. Loggerhead turtle
populations have fallen by 90 per cent in the last two decades.
Nor are bycatch reduction devices compulsory, despite the bycatch comprising
as much as 90 per cent of commercial catches. Although there is evidence that
illegal fishing is widespread, vessel monitoring systems (VMS), which would
reveal the extent of illegal fishing in the few areas closed to trawling, are
not used. And no research is being conducted into alternatives to prawn
trawling, such as prawn traps. Finally, the Queensland government, which is
responsible for managing fisheries on the Great Barrier Reef, is considering
amendments to the Fisheries Act regulations which would allow trawling to target
new species and to legalise previously illegal bycatch.
The myth that the Great Barrier Reef is being protected, either by research
or by management, is nowhere more demonstrably false than in the instance of
trawling. It is the most destructive and least ecologically sustainable practice
on the Great Barrier Reef. It is an obsolete technology that does not belong in
any area where one values the health of the marine ecosystem.
Moral veg
Simply labelling foods to say that they do or do not contain genetically modified organisms
(This Week, 30 May, p 25)
will do nothing to encourage an informed debate.
If the public are to make intelligent decisions about GMOs, surely foods
should carry labels stating the purpose of the genetic modification. For
example, I would have no worries about potatoes modified to resist
Phytopthora, the fungus that caused the Irish potato famine, or vegetables
modified to enhance useful compounds such as sinigrin. I would, however, be less
than keen to consume crops modified to allow them to be drenched with
herbicides, or those for which the primary reason for modification was to allow
transnational corporations to gain control over the world’s food production.
Probably not
Max Tegmark’s theory that all possible universes exist
(“Anything goes”, 6 June, p 26)
is intriguing, but it seems to buck basic ideas about the nature of
probability.
Tegmark argues that the only universes that will be “perceived” are the ones
containing life, and that since the likelihood of life arising is spectacularly
small, countless other universes incapable of supporting life must also have
arisen. However, Tegmark is arguing from a post-event perspective from which the
event does indeed look remarkable.
Take, for example, a crash involving two vehicles. Looking back on the
accident, the series of events that led to the crash seem to be an incredible
series of coincidences and bizarre twists of fate which would be impossible to
predict. Suppose one of the drivers had started out a minute earlier, or that a
set of traffic lights had changed slightly later, or that one of the drivers had
taken a different route. In any of these events, and a million others, the
accident would not have happened. And yet the mangled wreckage tells us
emphatically that it did.
Furthermore, the probability that the accident is/was going to occur changes
with the proximity to the event itself. A week before the event the chances of
it happening are virtually nil, but a split second before, the chances of a
collision are very high indeed. In other words, the probability of a particular
event occurring is not static but changes with time.
When we view an event such as the origin of life in the Universe, we can
indeed marvel that conditions were so suited to such an event occurring. But, as
Tegmark himself argues, we are only able to perceive the event precisely because
life has arisen in the Universe. In our retrospective view, the event, like the
car accident, has become a certainty arising out of what were once seemingly
impossible odds. This, in itself, does not make it remarkable, or argue for
other parallel universes in which different physical laws operate. It merely
confirms that a series of events took place, and that one of the results was a
life form that could reflect on it in the pages of New 杏吧原创.
Letter
An irrelevant mathematical point: Max Tegmark’s method for generating all
numbers between 0 and 1 misses most of them. In particular, it misses all those
numbers with infinite decimal expansions that he sought to catch.
I don’t think that this invalidates his argument concerning information
content and complexity, but a better analogy should be chosen.
Rest in peace
Joseph Strout
(Letters, 23 May, p 57) may or may not be justified in hoping
that in a hundred years’ time humanity will be able to restore frozen bodies to
life. But even if it can be done, why should it be?
The future which Strout looks forward to will be a pretty crowded place, as a
society which can raise the dead must have long since achieved the lesser aim of
halting the ageing process. If death becomes a choice rather than a necessity,
how many people would be prepared to move on and leave their assets and
resources to a new generation?
There would be no reason for adding to the population people that nobody
living will know or care about, who will be helpless in a strange society, and
who have in any case lived out one life already. It is far more likely that the
people of that time will give priority to the needs of their own generation and
let the dead rest in peace.
Enzyme agent
I, like Richard Simons, read Greg Forbes’s letter about the trouble
organisations from smaller countries have in obtaining supplies
(Letters, 21 February, p 53, and
23 May, p 56).
I got in touch with Forbes by e-mail and had
a most enjoyable time tracking down restriction enzymes and other reagents.
I found that some of the larger companies were not deliberately ignoring
orders, but were just too disorganised or too rigidly structured to help. I
discovered a supply of the enzyme Forbes wanted at a warehouse owned by a large
company in Germany, but the company representative in Britain could not get it
for me. He was not allowed to buy from his owner and e-mails to his boss in
Germany went unanswered.
Smaller companies, however, were extremely helpful. The team at Cambio went
above and beyond the call of duty to get enzymes packed in ice to Ecuador before
the ice melted. Sylvia Dunbar at Scientific and Technological Supplies moved
heaven and earth to track down a small piece of 40-micrometre mesh that could be
safely autoclaved. Throughout my search I was unfailingly met by kindness,
courtesy and good humour and I would like to thank everyone that helped.
If anyone else is having trouble obtaining supplies of any sort, please get
in touch as it makes a retired teacher very happy.
Sound sense
There are millions of unexploded landmines in the Libyan desert and
elsewhere. A novel way to destroy them could be the sonic boom generated by a
supersonic aircraft.
Detonating a mine takes a pressure of about 500 pascals acting downward, as
from a walking human. Measurements on sonic booms often generate 50 to 500
pascals, and with a diving aircraft a pressure of up to 1400 pascals is
possible. The largest pressure recorded is 7000 pascals. As the duration of a
boom can be up to a quarter of a second, considerable impulses are possible.
The idea could be tested in a remote area containing a number of
antipersonnel mines by a pilot flying an aircraft such as an F111 at supersonic
speeds at low altitudes over the area, either horizontally or making a dive at
the mined area. If the method works, the landmines will be detonated by the boom
very soon after the aircraft has passed.
Both Ray Stalker and Jim Ward have encouraged my thinking on these matters.
The data quoted are from Robert Lee of the US Air Force.
Tale of two times
Kenneth Hooton asks why the telephone number of Britain’s Millennium
Commission is 0171 880 2001
(Letters, 6 June, p 66). The Millennium Commission
is aware that the millennium actually begins on 1 January 2001. However, all our
enquiries indicate that the public wish to mark the year 2000. The commission’s
fax number is 0171 880 2000, which means that we cover both schools of thought
as to when the new millennium actually begins.
Brick work
Further to John Heathcote’s letter regarding reducing speeds in order to
reduce fuel consumption
(Letters, 6 June, p 65), I recall a physics lesson
where the teacher was explaining that we consume fuel to accelerate and then
dissipate the energy acquired when braking. He suggested that by putting a brick under the
accelerator, energy would be saved by not being able to accelerate rapidly.
One of my classmates was then quick to point out that the energy was lost in
braking and that a brick under the brake pedal would be a far better solution.
Needless to say, no tests have yet been undertaken.
Naked truths
I thought the letter moaning about the cover of the 23 May issue was a bit silly
(Letters, 13 June, p 51). I don’t think the picture was sexist or
exploitative. But I did take a look at some back issues and you do use nude
imagery quite frequently. I find none of it offensive, and think the visual
content of New 杏吧原创 is well integrated with the stories, with lots
of exciting graphics. If anything was offensive in the cover article “Hidden
truths” it was surely the drug injector.
A light shower
The effect achieved by Pontus Lurcock by placing unwanted CDs into a
microwave also works for credit cards
(Letters, 30 May, p 58).
The hologram on my wife’s gold card exploded in an extremely satisfying
shower of sparks which, I thought, would prevent it being used on any further
expensive forays such as the one which prompted this action.
My wife, however, had other ideas and retrieved the card. The uselessness of
the hologram as a security measure was proved by her continuing to use the card
until its expiry date. Not a single shop assistant asked her why the hologram
had been replaced by a small blast crater.