High expectations
With reference to the letter from Michelle Tobin about motor neuron disease
(10 March, p 56),
I was wondering when people in the richer countries of the
world began to expect medical sciences to cure any ailment, no matter how
rare.
What do ill people in poorer countries expect? Do they think it is just one
of those things, and wait to die?
God, ether and psi
You held an interview on “parapsychology” and the so-called Ganzfeld experiments
(3 March, p 46). My own view is that “psi” is as great
an opportunity for self-deception and fraud in the 20th and 21st centuries as
spiritualism was in the 19th.
Consider: evolution by natural selection works, and favourable
characteristics are selected for. If there was such a thing as any form of psi,
this would give its possessors an enormous cultural and physical advantage. Even
a 1 per cent advantage would show up very quickly, as computer simulations of
eye development show.
No such advantage has been seen or detected. Therefore it is either
non-existent, or is not detectable (like the luminiferous ether, or “god” ).
Please stop wasting time, paper and effort over such nonsense. Those of us who
are rationalists have enough problems with religious loonies.
If music feeds the mind, play on
The practice of listening to music while studying has been around and
tested repeatedly for nearly 40 years. So I am surprised at the generalisation
in your report suggesting we should “kill the music” if we want good grades
(17 March, p 17).
Proponents of music as an aid to study such as Georgi Lozanov say
that only specific kinds of music should be played鈥攎any of the baroque
composers and Mozart, for example鈥攁nd the music must be used in a
carefully controlled manner, not just blaring away in the background or over
headphones.
I have personally used this approach with great success in various
contexts鈥攊ncluding training computer programmers and sixth-form students
(and myself)鈥攐ver a period of 20 years.
Researcher Sarah Ransdell responds: Sweeping generalisations are never the
intention of individual experimental reports. The experiment merely indicates
that music was disruptive in the instance described. Humans are flexible and can
be trained to do many things. With rather extensive practice, some college
students can read aloud while simultaneously taking dictation on another topic.
I, however, will continue to read and write in perfect, blissful silence.
Way to go
“Astronomy by distance learning” proclaims an advert
(17 March, p 115).
How else?
Ignore the alarm
Your item reporting that people in the Microsoft building in Seattle ignored
klaxons and flashing lights during the earthquake
(Feedback, 17 March) touched
on a hot topic in the sound reinforcement industry at present. Voice
announcements are vastly more effective in getting people to evacuate a
building, or whatever else is required, than any number of bells, whistles and
lights. So the technology of voice-alarm systems and the intelligibility of the
speech messages they deliver are under intensive study.
Apropos of which, you may like to know that one morning last year in a hotel
in the West Midlands, a bell began to ring. No one in the conference room took
any notice. A few minutes later, hotel staff apologised for the “disturbance
caused by the fire alarm being set off”. “We were not disturbed,” was the
response, “we were too busy agreeing with each other that you should have a
voice-alarm system instead of a bell that everyone ignores. That’s what this
seminar is about.”
The risk is real
The letter by Martin Savage concerning the asteroid impact hazard
(24 March, p 57) was seriously misleading.
Savage asks, “How many people altogether have been killed by asteroids,
ever?” In reply one might ask: “How many people have ever been killed by
hydrogen bombs?” Although the answer is zero, we know that such devices are
dangerous, and act accordingly. So it is with asteroids.
Discussion of extinction events is irrelevant. The asteroid hazard is
dominated not by the extremely large impacts that cause extinctions, which occur
very infrequently, but impacts close to the threshold for causing a global
environmental catastrophe. An asteroid between one and two kilometres in size
would just about do it.
Such an event happens at least once every few hundred thousand years, and
we’d expect it to kill around half of all humans. That places the hazard well
into the “intolerable” region in the matrix of probability versus consequences
that governments use to decide how to respond to possible major disasters.
Savage also suggested that radar should be used to search for asteroids,
rather than optical telescopes. The laws of physics prohibit this. The returned
echo drops off as the fourth power of the range, and asteroids are mostly at
ranges of more than 100 million kilometres.
Unlike aeroplanes, the line-of-sight velocities of asteroids are significant
compared to the speed of light, and therefore the Doppler effect shifts the
echoes to frequencies outside of the receiver’s range. Planetary radars operate
at centimetre wavelengths, and the cross-section of back-scatterers in space is
dominated by small meteoroids with sizes of that order. So looking for asteroids
using radar is like looking for a snowman in a snowstorm.
Radars of this type are, however, of immense value for working out the orbits
of asteroids we already know about, so long as they come close enough to the
Earth.
Any form of asteroid search involves a consideration of the signal to noise
ratio. Unfortunately Savage’s letter added no signal, only noise, to the
debate.
Name that tune
John Gratwick’s letter about Denys Parsons’s Directory of Tunes is
interesting, but does not go back far enough
(10 March, p 57).
I have a copy of the Dictionary of Musical Themes by Barlow and Morgenstern,
first published in 1949. This transposes all tunes to the key of C (major or
minor). It includes sharps and flats, but omits octave and note-length
information. This is more detailed than Parsons’s approach, except that there is
no distinction between, say, CG up a fifth and CG down a fourth.
Using Barlow and Morgenstern requires a little more musical ability, but
should lead to more focused search results with shorter “words”, and better
musicological information.
Humming ahead
I was amazed that the article on search engines which can find a tune you hum to them
(17 March, p 34)
didn’t mention the research by anyone who has published
in the field of music information retrieval (MIR).
Perhaps you should point your readers to the following URL for more
cutting-edge research in this field: http: ciir.cs.umass.edu/music2000/.
Information on most MIR research groups and their projects can be found at this
site.
Wish upon a star
Your report on Jay Melosh’s work
(17 March, p 4) mentions how a
microbe-infested rock from Earth or Mars might reach another solar system, tens
of light years away. The odds are pretty small.
There is, however, a mechanism that might increase the chances of rocks being
exchanged between planetary systems. The stars might come to us.
In 1981 Jack Hills published a paper on comet showers and the steady-state
infall of comets from the Oort Cloud. While looking at a possible cause of comet
bombardments, he estimated the mean time between stars passing close to our
Sun.
Over the lifetime of the Earth, about four star systems may have come within
1000 astronomical units of the Sun. Every 100 million years or so a star system
passes within 3000 AU. It would be interesting to work out the odds of a
microbe-bearing Earth rock finding its way into this region of the Solar System
and then being picked up by a passing star and landing on a suitable planet. No
doubt they are extremely poor odds鈥攂ut better than those on travelling 10
light years or more through empty space.
While a star was passing near the Solar System, you would expect the Earth to
be bombarded by comets dislodged from the Oort Cloud over a period of several
years. The number of rocks launched bearing microbes could therefore increase
during this period, improving the odds of transpermia (the exchange of life via
meteoroids) succeeding.
Robin Oliver revisited
The reference to Robin Oliver’s “outstanding contributions to the geology of Sri Lanka”
(Feedback, 17 March)
seems perfectly correct to me. Geology is the
scientific study of the history, composition and structure of the Earth, and so
his contributions were actually to the study of Sri Lankan rocks.
Nevertheless, Robin was indeed an awesome character, and one I am privileged
to have known. He was equally renowned for his contributions to Antarctic
geology, in which he was still actively engaged until just before his death at
the age of 79. He was still doing fieldwork there under arduous conditions into
his sixties, at least.
Oliver also had a reputation as a somewhat absent-minded academic. Going home
from the university one day, he went to where he thought he had left his car,
only to find it missing. This was duly reported to the police, and he made his
way home by other means. The following night he went to where he had actually
left his car the previous day, and was stopped on his way home by the police for
driving a stolen car.
On another occasion he interrupted a lecture he was giving to go and collect
something from his office. However, he sat down at his microscope and started
working instead, and totally forgot about his waiting students.
Living off autism
Referring to the letter from Ken Aitken
(10 March, p 56), I have a heretical
and thus unsubstantiated belief that the alleged increase in reported cases of
autism arises from two factors.
First, as mentioned in New 杏吧原创, there’s the ever-broader definition of
what constitutes autism spectrum disorders. Secondly, there’s the autism
business, which drives this process.
This is an admittedly unkind summary of the worldwide growth of specialist
service providers, both charitable and commercial, research institutes and
centres with their core staffs in the necessary disciplines, and teachers,
administrators, fund-raisers, and so on. All of these have, sadly, a vested
career interest in autism. It may be that, to crudely paraphrase C. Northcote
Parkinson, autism expands with the number of people making a living from it.
No more swill
In Ireland, feeding animals on swill was banned in 1985
(17 March, p 11). The
likelihood that two disease outbreaks in Britain鈥攕wine fever last year and
foot and mouth this year鈥攐riginated from waste food illustrates the
problem that this ban addressed.
Farmers within the European Union must generally produce food in strict
compliance with animal, human and environmental welfare provisions. But much
food is imported from elsewhere, and often produced under sub-standard
conditions. This is a direct cause of the over-intensification of farming within
the EU as farmers fight for economic survival.
The solution must include regulation of the catering trade. This supplies
nearly half of all food consumed, but its sources of supply are hidden from the
consumer. All importers should have to give guarantees that the product has been
produced in compliance with a strict set of minimum standards.
We cannot base our food security merely on the low cost of unsustainable
production elsewhere. What happens when all the rainforests have been cut down,
and the slaves living on $30 a month revolt?
Letter
Don’t keep us in suspense: what are the first few digits of the Omega
number?
All digits of Omega are by definition unknowable鈥擡d
Letter
Everyday structures鈥攈ouses, offices and airports, for example鈥攁re
essentially empty spaces. Only a small proportion of the occupied space is the
structure.
It’s easy to think of many beautiful structures whose elements occupy a tiny
proportion of the available space.
So is Chaitin really casting mathematics into disarray? Number theory, for
example, was not exactly cast into disarray by the realisation that there is a
more than infinite鈥� a transinfinite鈥攏umber of numbers between
any two integers.
Letter
Your article and Chaitin use the word “randomness” in a curious way. The word
“randomness” seems to imply that a number (for example) follows no pattern at
all.
However, you are assuming too much. Simply because we human beings, using our
mathematical tools, are incapable of discovering a pattern in something does not
imply that no pattern exists. In fact, we just don’t know. It’s certainly not
inconsistent to say that the Universe could be shaped according to a pattern
that we have no way of discovering.
If we agree that human beings will always have a finite amount of
mathematical knowledge, then no matter how hard we work we will still have
discovered nothing compared with the amount of mathematical knowledge that’s
actually “out there”. The alternative is to defend the (bizarre) proposition
that there is a finite amount of mathematical knowledge.
It should then be less surprising that the known connections between
different branches of mathematics are weak. There are infinite possibilities for
branches and for branching from every branch.
One might say that the philosopher Friedrich Nietzsche knew all this more
than a century ago. Mathematics was, to him, the language by which human beings
attempt to describe and understand their world. Nothing more. Who says
philosophy doesn’t have any “real world” implications?
Omega man
For me, Gregory Chaitin’s new number, Omega
(10 March, p 28), only
strengthens the notion that maths is a faithful description of reality. Surely,
in a Universe rich in singularities, we should expect a mathematics similarly
anarchic and porous. Just as anything lying “outside” our Universe is
fundamentally unknowable, so too is Omega. It looks like the numerical
equivalent of an event horizon.
Correction
Several readers have written to suggest that the “Samuel Clements
Twain” mentioned in Feedback
(17 March)
was in fact Samuel Langhorne Clemens,
who wrote under the pen-name Mark Twain.
As every (American) schoolchild knows. . .
Dotty com
A while ago, Feedback was looking for odd e-mail addresses
(10 February).