On space and time

The problem with Christmas is that it interferes with the right to freedom of mobility. Hence, as Yuletide approaches each year, I initiate a search programme to find a book or paper of depth, clarity, originality, and elegance, which will sustain me through this bleak period. This year, I was amply rewarded when I discovered On Space and Time, a collection of essays at the interface between physics and philosophy, a matter of days before 'festive' ground-zero.

The book contains lengthy articles by Shahn Majid on duality and self-duality, and Alain Connes on his non-commutative approach to space-time and particle physics, but the outstanding contribution is a 50-page exposition from Roger Penrose of his conformally cyclic cosmology.

With the apparent discovery of dark energy, and the accelerating expansion of the universe, the far future of our universe is representable by de Sitter space-time. Penrose noticed that the future conformal boundary of de Sitter space-time is spacelike, hence it can be joined to the spacelike initial conformal boundary of a Friedmann-Robertson-Walker ('Big Bang') model. The fact that the universe is very small and hot at the beginning, and very large and cold in the far future, is not a problem, argues Penrose, because both the early universe and far future universe contain only conformally invariant, massless particles. Without massive particles, there is no way of defining lengths or times, hence the only physically meaningful structure is the conformal structure, i.e., the causal structure. By compressing the conformal factor towards the far future, and expanding it towards the beginning, the geometry of the future conformal boundary can be joined seamlessly to the initial conformal boundary.

Penrose proposes that the far future of our universe contains only electromagnetic radiation and gravitational radiation. The electromagnetic radiation comes from the cosmic background radiation of the Big Bang, from stars, and from the eventual evaporation of black holes. The gravitational radiation, meanwhile, comes mostly from the coalescence of black holes. Penrose proposes that massive particles such as electrons, either annihilate with massive particles of opposite charge (positrons), or decay by some as-yet undiscovered mechanism.

The cycle of Penrose's model is one in which the universe 'begins' in a conformally invariant state, with zero Weyl curvature, but in which there is a normal derivative to the Weyl curvature. This seems to trigger the formation of massive particles. The matter then clumps together into stars and galaxies, such clumping increasing the Weyl curvature and decreasing the Ricci curvature. Eventually, much of the matter is swept into black holes, where the Weyl curvature diverges, but the Ricci curvature is zero. The matter which isn't swept into black holes decays or annihilates into radiation, and the black holes eventually evaporate themselves into radiation. The Weyl curvature thereby returns to zero, all particles are massless again, and conformal invariance resumes. Gravitational radiation, however, never thermalizes, and this appears to be responsible for the normal derivative to the Weyl curvature, which triggers the formation of massive particles in the next cycle.

Two potential problems spring to mind. Firstly, following an argument by Gibbons and Hawking, de Sitter space-time is widely believed to possess a minimum temperature due to its cosmological constant. With the value of the cosmological constant we observe, this temperature is about 10^-30 Kelvin. A black hole will only evaporate if the temperature of its horizon is greater than the temperature of surrounding space. The temperature of a black hole is inversely proportional to its mass, and a black hole which grows large enough that its temperature drops below 10^-30 Kelvin would never evaporate. However, such a black hole would have a mass approximately equal to the current observable universe, so the formation of such a black hole may well be impossible in a universe whose contents are diluted by the accelerating expansion of dark energy.

The second problem is that if the quantum fields in the far future of our universe can be treated as quantum fields in thermal equilibrium in de Sitter space-time, then because such a universe is eternal, quantum fluctuations ensure the spontaneous generation, at a constant rate, of anything you care to name, including massive particles and black holes. This would prevent our universe from ever reaching an exact state of conformal invariance in the far future. However, because gravitational radiation never reaches thermal equilibrium, one could perhaps argue that the quantum fields in the far future of our universe cannot be treated as quantum fields in thermal equilibrium in de Sitter space-time.

Penrose's proposal remains fascinating and elusive. A perfect antidote to Christmas.

Roger Penrose Conformally cyclic cosmology

Root and branch

With hope crumbling through my fingers into disappointment, and my ribcage crushed under the weight of solitude, I stumble out into the damp grey of a denuded winter landscape.

I walk along muddy tracks through leaf-strewn woods, summer canopy now gone, skeletal trees exposed to the featureless sky. Fungi feed voraciously on the body of one fallen sentinel; elsewhere, different species of moss compete to draw succour on the bole of an uprooted comrade.
Then, at the end of the path, I find him beside a shallow pool, contorted branches frozen in agony. At night, his suffering becomes animate, and he bellows with rage and pain, hammering a lignum fist into the stagnant water. The others look away, and quake as his dying anger throbs inconsolably.

Ferrari's 'general help'

A Captain ought, among all the other actions of his, endeavour with every art to divide the forces of the enemy, either by making him suspicious of his men in whom he trusted, or by giving him cause that he has to separate his forces, and, because of this, become weaker. (Macchiavelli, N. 1521. The Art of War, Book VI).

Ferrari President Luca di Montezemolo suggested this week that Bernie Ecclestone was running F1 as a dictator, that he should step aside sooner rather than later, and that the F1 teams required both a greater slice of the commercial revenues from F1, and a greater 'transparency' about those revenues.

In response, Bernard was moved to publicly specify, for the first time, the extra financial benefit Ferrari receives from the commercial revenues, and to also acknowledge that Ferrari have for many years been the beneficiaries of something he termed 'general help':

"The only thing [Montezemolo] has not mentioned is the extra money Ferrari get above all the other teams and all the extra things Ferrari have had for years – the 'general help' they are considered to have had in Formula One.

"Ferrari get so much more money than everyone else. They know exactly what they get, they are not that stupid, although they are not that bright, either. They get about $80 million (about £54 million) more. When they win the constructors' championship, which they did this year, they got $80 million more than if McLaren had won it."

General help. Now there's an interesting phrase. Of what does this general help consist, one wonders? Perhaps Bernie and the governing body, the FIA, have been giving advice to Ferrari team members on how to ensure that their motions are regular as clockwork each morning. Or perhaps the FIA have provided tips on the best holiday destinations, advice on how to improve one's memory, and methods for getting a good night's sleep.

The Formula 1 teams have recently formed a united front (FOTA, the Formula One Teams Association), to represent their interests against those of the FIA, and the private equity company, CVC, which owns the commerical rights to F1, and whose F1 companies are operated by Bernie Ecclestone. Ferrari President Luca di Montezemolo has been acting as the spokesman for FOTA, given that Ferrari wield the greatest amount of political clout.

FOTA are seeking a greater proportion of the commercial revenue generated by F1, and Bernie is seeking to prevent this with a divide-and-conquer technique. By implying that Ferrari have indeed received something more than financial assistance from the powers-that-be, Bernie is seeking to fuel the beliefs amongst Ferrari's rivals that F1 is not a level playing field. The phrase 'general help' is sufficiently ambiguous that it can be clarified and neutralised at a later stage, but is, nevertheless, designed to make McLaren-Mercedes, Renault, BMW, Toyota et al wonder if they really can trust Ferrari.

One hopes that FOTA have anticipated this tactic...

Bernie Ecclestone Luca di Montezemolo

Amanda Gefter

I've recently stumbled upon Amanda Gefter, an editor for the Opinion section of New Scientist. Amanda studied the philosophy of physics at the London School of Economics, and writes about cosmology, so I guess there is a certain similarity of background. Moreover, Amanda is also very interested in science and religion. A couple of months ago she wrote a timely article which drew attention to the latest tactic of the creationists, (and their apologists, some of whom, it must be said, write for British newspapers):

"They are attempting to resurrect Cartesian dualism - the idea that brain and mind are two fundamentally different kinds of things, material and immaterial - in the hope that it will make room in science both for supernatural forces and for a soul."

Amanda also spoke to Michael Heller earlier in the year, and concluded that

"Heller comes across as a contemplative, kind and brilliant man with an impressive intellectual range, flitting easily between talk of complex philosophical ideas and sophisticated mathematical physics. (I was intrigued that his current work is focused on ridding physics of the big bang singularity - despite the fact that many Catholics have latched on to the idea of the singularity as the space left for God and his creative power.)"

I wonder if Amanda also gets asked "What on Earth is the philosophy of physics?"

Amanda Gefter Michael Heller Creationism

The coldest start to December since...

Whilst many news outlets reported that the beginning of December in the UK was the coldest since 1976, the reality is slightly more subtle, and depends upon the definition of 'the start of December'.

Meteorologist Philip Eden reports that the 1st to the 7th, and the 1st to the 8th were the coldest since 1998; the 1st to the 9th was the coldest since 1980; the first to the 10th was the coldest since 1976; the 1st to the 11th was the coldest since 1981; and the 1st to the 12th, 13th, 14th and 15th were merely the coldest since 1991.

Philip Eden

Mark Hughes wins Irish sports book of the year

In September, I predicted that Crashed and Byrned, the story of Tommy Byrne's rise to the cusp of Formula 1 stardom, and subsequent decline, would "become the most acclaimed sporting book of the year." Like all McCabism predictions, this hasn't quite turned out to be totally accurate. Nevertheless, author Mark Hughes was this week awarded the William Hill Irish Sports Book of the Year for 2008, which by my standards, counts as a preternatural level of judgement and foresight.

Tommy Byrne Mark Hughes

A comprehensible universe

One of the most neglected books published in 2008 was Father George Coyne and the Reverend Michael Heller's short work, A Comprehensible Universe. Coyne and Heller provide an urbane and informative guide to the development of the scientific method, and its historical relationship to Greek philosophy and the Judaeo-Christian religion. Both authors possess a professional understanding of science and cosmology, and provide a reliable, non-technical guide to the subject matter.

I've always considered that philosophers and scientists should work in castles or palaces, hence this recollection from the Preface particularly caught my attention:

Both authors met at the Vatican Astronomical Observatory in the Pontifical Palace amidst the bucolic surroundings of Castel Gandolfo where the papal summer residence is located. During long evenings, when the autumn winds went howling through the labyrinth of corridors and staircases in the palace,...they started working on the English version of the manuscript. While working together at Castel Gandolfo it was often easier and quicker for the co-authors to communicate via e-mail than to search for one another in the vastness of the palace.

Coincidentally, there is an excellent Richard Dawkins interview with George Coyne on the former's website. Dawkins allows Coyne to speak at length, and whilst he naturally challenges some of Coyne's opinions, the interview is far from confrontational.

George Coyne Michael Heller

Near-death experiences

Christian author Bryan Appleyard writes an article for The Sunday Times which argues that near-death experiences (NDEs) are evidence that the mind can be separated from the brain, and there actually is an afterlife.

Bryan refers to the "consistency and clarity of these [NDE] reports across cultures and time zones," which is misleading, not only because people of different religions see different religious figures in NDEs, but as Carol Zaleski detailed, "through her comparative studies of medieval and modern NDEs, many features of these experiences vary in ways that correspond to cultural expectations. A striking instance of this is the minimal role played by judgment and damnation in modern NDEs; unlike the medieval cases, the modern life-review tends to be therapeutic in emphasis. In view of this, Zaleski ascribes the experiences to the religious imagination."

As Appleyard himself points out, "all the evidence [for NDEs] remains anecdotal, and even the most impressive stories...tend to look less convincing on closer examination." Moreover, as Michael Shermer explains, the hallucination of flying is triggered by atropine, out-of-body experiences are triggered by ketamines, the perception of the world enlarging or shrinking is triggered by dimethyltryptamine, the retrieval of long-forgotten memories is triggered by methylene-dioxyamphetamine, and a feeling of oneness with the cosmos is triggered by LSD. "The fact that there are receptor sites in the brain for such artificially processed chemicals means that there are naturally produced chemicals in the brain that, under certain conditions..., can induce any or all of the experiences typically associated with a NDE," (Why people believe weird things, p80).

Bryan attempts to support a dualistic approach to the ontology of the world, by arguing that thoughts cannot collide with bricks. "Dualism," says Appleyard, "means that the mind and the brain are not made of the same things and therefore in theory, they can be separated, as in NDEs." However, in general, an object cannot collide with a process. For example, a brick cannot collide with evaporation, but this is hardly evidence of a fundamental ontological duality. Moreover, if non-collidability enables the mind and the brain to be separated, it follows that computer software can also be separated from computer hardware. Presumably, a terminating program will briefly float at ceiling level in the IT department, above the computer it was running on, before it enters a cybernetic afterlife.

Most remarkably, Bryan takes huge liberties with the interpretation of quantum theory, and claims that it supports mind-brain dualism, quoting with approval the eccentric opinions of Henry Stapp. "'The observer,' Stapp tells me, 'is brought into quantum dynamics in an essential way not only as a passive observer but as an active part of the dynamics'." This is the familiar canard that observers are a crucial part of the quantum world because it is observers who trigger wave-function collapse. In fact, wave-function collapse is triggered by any measurement-like interaction, and observers are completely superfluous to the process. Appleyard even claims that "quantum non-locality could mean the mind is capable of being non-local to the brain, of floating to the ceiling of the room." Quantum non-locality pertains to non-local interactions between particles separated over large distances, and entails no such possibility of separating the mind from the brain.

There seems to be a quite remarkable degree of selection and manipulation of the facts going on here. Appleyard is twisting some well-known canards in the interpretation of quantum theory, to provide a post-hoc justification for a belief about the nature of the mind which is crucial to his religious world-view. Honesty and integrity seem to have taken something of a backseat here.

Near-death experiences Bryan Appleyard Mind-brain dualism Quantum non-locality Henry Stapp

Airbours

If airports are the aeronautical equivalent of seaports, then why don't we have aeronautical equivalents of harbours? In particular, why don't we have aeronautical correlates of Monte Carlo, places where millionaires can dock their aircraft, spend some time in a casino, and then party with their rich friends on the wings of their opulent flying palaces?

I'm thinking of a sort of Cloud City here, which, in the absence of anti-gravity generators, could perhaps be suspended by the simultaneous downward thrust from a hundred or so jet engines, or just by, well, lots of helium balloons. The technology is already there, so let's do it, I say.

Airbours Cloud city

The naughtiness factor

The British Journal of Tabloid Mathematics (aka The Sun), proposes a formula for the naughtiness factor of a low-cut dress:

O=NP(20C+B)/75 ,

where N is the number of nipples exposed, from zero to two, or expressed as fractions of nipple shown; P is the percentage of exposed frontal surface area; C is the cup size factor, set to 1 for an A-cup, 2 for a B-cup, 3 for a C-cup, and 5 for D-cup or greater; and B is the bust measurement in inches. The Sun claim that a value of O greater than 100 indicates obscenity.

The Sun claim that the Roberto Cavalli dress worn by Britney Spears this week "showed off around 70 per cent of her breasts, and experts at Wonderbra think she is a 32D. Without any nipple exposure, Britney’s formula works out as 0x70x(20x5+32)/75 = 123.2 ."

Unfortunately, the suggested formula entails that if zero nipples are exposed (N=0), then the naughtiness factor is always zero. I propose modifying the formula as follows:

O=[(N+1)/1] P(20C+B)/75

This enables us to recover a value of O=123.2 for Britney's dress.

Britney Spears

Physicists vs. economists

J. Doyne Farmer of the Sante Fe Institute, makes an interesting claim in Nature about the two cultures involved in quantitative finance, namely those of physicists and economists:

"Quantitative hedge funds tend to divide into those run by economists and those run by scientists from other disciplines, such as physics, maths or computer science...This distinction is not just a matter of professional pride and disciplinary boundaries...economists and physicists traditionally approach the problem of risk control in different ways. Risk control is the art of determining the likelihood of large and unexpected price changes happening in the future. It is well known that extremely large changes, and financial crashes in particular, are more frequent than would be expected from a 'normal' statistical distribution. Physicists tend to favour a 'power law' mathematical description to model the heavy tails of these distributions, giving a pessimistic view of the likelihood of large price movements. By contrast, the economists...spoke about price movements in terms of standard deviations, a terminology that is only relevant for normal distributions. This demonstrates that they were not thinking about the problem in the right way...Wall Street should follow the conservative approach to risk control that arises from properly modelling risks as power laws."

It's certainly true that econophysics recognized the existence of power law distributions, as this excellent paper by Dean Rickles exemplifies. I suspect, in addition, that there are also plenty of financial institutions in which physicists and mathematicians were responsible for developing the quantitative models, but in which economists and financial managers were responsible for the interpretation and application thereof. It is the latter group of individuals who would have largely been responsible for not incorporating the consequences of power law distributions into their value-at-risk calculations.

Power law Value at risk Financial collapse

Diodes made of neurons

There are three distinct positions in the philosophy of the mind of greatest contemporary relevance:

1) Eliminative materialism: The brain exists, but the mind does not.

2) Identity theory: The mind and the brain both exist, but the mind can be reduced to the brain in the specific sense that the mind can be identified with the brain.

3) Functionalism: The mind and the brain both exist, and the mind super-
venes on the brain, but the mind cannot be identified with the brain.

Functionalism embraces the notion of substrate-independence, the claim that the mind could supervene upon multiple substrates, of which the brain just happens to be one example; if there are multiple substrates which could support the mind, then one cannot identify the mind with the brain.

The December issue of Nature Physics reports that Ofer Feinerman and colleagues have developed a technique to grow neuronal cell cultures capable of performing any desired computation. By encouraging the self-organization of neuronal networks, Feinerman et al were able to synthesize neuronal diodes, AND gates, and threshold devices. These components are sufficient to assemble any desired logical circuit.

Hence, Feinerman et al appear to have experimentally demonstrated substrate-independence. Diodes, for example, can either be made of neuronal networks, or they can be made of semiconductors.

Neuronal networks Functionalism Philosophy of Mind Diodes

Ricky Gervais, String theory, and Quimballs

Radio 5 are getting into something of a Christmas routine these days. First it's the Mark Kermode Advent Calendar, then Jeremy Clarkson pops up to flog his annual DVD, and then shortly afterwards Ricky Gervais makes an appearance to promote his latest DVD. Ricky, however, is something of a McCabism hero, and, in this year's chat with Simon Mayo, he points out that: (i) the egg came before the chicken; (ii) most people are stupid; and (iii) strings cannot be elementary particles because you can cut them in half.

This is an important point, because physicists such as Lee Smolin argue that the notion of unification requires the different kinds of elementary particle to be merely different states of a single underlying elementary entity, and argue that string theory permits this, where the notion of a point particle doesn't: "If the elementary particle was something of a certain size, there would be no difficulty imagining it to exist in different states. It might be, for example, that the particle could take on different shapes. But it is hard to imagine how something that is just a point, that has no shape and takes up no space, could exist in different states or configurations...String theory resolves this paradox, because it says that the end of the process of reductionism is that the most fundamental entities are one dimensional strings and not points...it is [the] different modes of vibration of the string that are understood in string theory as being the different elementary particles," (The Life of the Cosmos, 1997, p65).

Gervais, however, points out that strings are actually composed of quimballs, which, in turn, are composed of two-for-quarkels and a strumpet. It's coruscating stuff from Reading's finest.



Ricky Gervais Radio 5 String theory Quimballs

God or multiverse?

I do not want to predict the future. I once predicted my own future. I had a very firm prediction. I knew that I was going to die in the hospital at the Academy of Sciences in Moscow near where I worked. I would go there for all my physical examinations. Once, when I had an ulcer, I was lying there in bed, thinking I knew this was the place where I was going to die. Why? Because I knew I would always be living in Russia. Moscow was the only place in Russia where I could do physics. This was the only hospital for the Academy of Sciences, and so on. It was quite completely predictable.

Then I ended up in the United States. On one of my returns to Moscow, I looked at this hospital at the Academy of Sciences, and it was in ruins. There was a tree growing from the roof. And I looked at it and I thought, What can you predict? What can you know about the future? (Andrei Linde).

Discover magazine has an interesting article by Tim Folger on the anthropic principle and the multiverse hypothesis. The article raises two important questions, the first of which concerns the power of scientific methodology to confirm the existence of other universes:

1) If you have a theory which explains the nature of our universe, and which entails, as a by-product, the existence of other universes, and if such a theory makes a prediction about our universe which is subsequently confirmed by observation or experiment, and if there is no other theory available with the same explanatory and predictive power, then does this constitute indirect evidence for the existence of those other universes? In other words, even if one cannot directly confirm the existence of other universes, does the confirmation of a theory which predicts other universes constitute indirect confirmation of the multiverse hypothesis?

The second question concerns the purported choice between God or a multiverse:

2) If there is no theory with explanatory and predictive power which entails that our life-permitting universe is the only logically possible universe, then is there a rational choice between the existence of a multiverse, in which all types of universe exist, or the selection and creation of our universe by a supernatural deity? What rational method could be employed to make such a choice?

The second question here presents something of a false dichotomy. One could, alternatively, accept the provisional inadequacy of our theoretical capability, but not abandon the notion that our universe is the only logically possible universe. One could also alternatively suggest that our universe was selected and created, not by a supernatural deity in the sense described within religious scripture, but by a non-supernatural intelligent being within another universe. One could suggest that our universe is a program running on a computer in another universe, or that our universe was created in a laboratory within another universe. These latter options are special types of multiverse hypothesis because they require the existence of other universes in which the creating agency exists, but they do have the novelty of combining the multiverse hypothesis with the notion that our universe was created by conscious choice, (although that itself is a special type of physical process).

Multiverse God Andrei Linde Anthropic Principle

An organic internet

On the Earth, evolution by natural selection has only evolved animals which communicate over distance by sound waves, and by light in-between the infrared and ultraviolet parts of the electromagnetic spectrum.

Is it possible, however, for a species to evolve organic radio/microwave-length transmitters and receivers, with which they can mutually communicate? In other words, is it possible for biological organisms to evolve transmitters and receivers as organs, or parts of organs? In effect, could a species evolve the organic equivalent of bluetooth connectivity between each other?

The energy requirements for such a communication system would be biologically onerous, but could a species not evolve its own rechargeable biochemical batteries, to supply the necessary energy?

Furthermore, if such a communication system could evolve by natural selection, and if an intelligent species on some planet were to evolve such a communication system, could an organic internet, a type of collective intelligence, not evolve on some planet?

Organic internet

Billions and trillions

I received the 2008 Pensions Scheme Update this week from the Trustees appointed by my employer. A covering letter from the Secretary to the Trustee, pointed out that "The recent turbulence in the financial markets has caused concern for many members."

Turbulence. That's an interesting choice of term. It implies that financial stability will be restored in the near future. When one thinks of turbulence, one thinks, perhaps, of the choppy wake from a motorboat, which might make things slightly unpleasant for a short period, but which will ultimately dissipate. More accurate alternatives to 'turbulence' include 'catastrophic shock wave', and 'collapse', but then I guess such phrases fail to reassure the anxious pension contributor...

Within the Pensions Update document was a subsection which explained what the credit crunch is. It was quite a nice summary, but it did contain the following paragraph. See if you can spot the error:

House prices in the US have now fallen by around 20% and may fall further. As the value of the packaged loans began to fall, the banks had to write down the value of these loans on their balance sheets. The International Monetary Fund estimate that banks will suffer losses of around $1 trillion, that's $1,000,000,000. The concern about falling property values has spread worldwide, for example to include mortgages in the UK as well as loans on commercial property.

Nice to know our pensions are in safe hands.

Pensions Credit crunch

Extra ordinary minds

This week, I visited an operation which has recently been bought by a French company, and which has consequently undergone a re-branding exercise.

As part of this re-branding, the slogan 'Extraordinary minds at work', was coined. Perhaps, however, something was lost in translation, as this teacup attests...

Light Sabers and fluorescent tubes

Watching the repeats of the original Star Wars trilogy on television recently, I was struck by a couple of things. Firstly, the woeful CGI scenes added by Lucasfilm in the 1990s, stand out like a gangrenous thumb. Not only do they fail to add anything to the orginal cut, they detract significantly from it. It is as if Leonardo da Vinci has been given the opportunity to revisit the Mona Lisa, and has chosen to spray-paint a couple of ears on her.

One particular piece of CGI, featuring a Landspeeder driving into Mos Eisley, is so poor that it would be castigated were it to appear in a PlayStation game; it's out of scale, out of perspective, has no variation in focus, and has an ersatz quality of light and colour.
The second thing I noticed is that the Light Sabres (note the spelling) produce light in a manner which resembles neon lighting, or fluorescent tubes. Sure enough, it seems that when Nelson Shin designed the Light Sabre, he reasoned that since the Light Sabre is made of light, it should look 'a little shaky', just like a fluorescent tube.

As explained with exemplary clarity by Dr Chris Smith, neon lights and fluorescent lights generate visible light by distinct mechanisms. In a neon light (or lights using other noble gases, such as argon, krypton or xenon), the tube is filled with a gas that simply emits visible light when stimulated with an electrical current, and the tube itself is transparent to the passage of this light.

In contrast, in a fluorescent tube, the visible light is generated by the interaction of two distinct light-generating processes. The tube in such a light is filled with a gas, in which luminescence is once again stimulated by an electrical current. In the case of a fluorescent light tube, the flow of free electrons excites bound electrons in a gas of mercury atoms, which then emit ultraviolet light when the excited electrons return to their initial energy levels. The light emitted by the gas in the tube is then absorbed by a fluorescent material, called a phosphor, which is deposited on the inner surface of the tube. This raises the energy levels of electrons in the phosphor, which then emit visible light when those electrons return to their former state. The colour of the light emitted by the phosphor depends upon the precise blend of metallic and rare-earth salts used.

Bloodhound SSC

'4.1 lactating cows', might sound like a description of Girls Aloud after their firstborn have been delivered, but it is in fact the equivalent to the CO2 output of Bloodhound SSC, Britain's latest World Land Speed Record challenger.

Not content with breaking the sound barrier, Richard Noble, Andy Green and the team are back again, this time aiming to hit 1,000mph. As explained by Gordon Cruickshank in the December issue of Motorsport magazine, Bloodhound SSC will be equipped with a Eurojet EJ200 turbofan engine from the Typhoon fighter, a solid fuel rocket triggered by a hydrogen peroxide oxidiser, and an 800bhp V12 internal combustion engine, which powers both the pump for the hyrodgen peroxide, and the vehicle hydraulics, and also acts as the starter motor for the jet. The pump itself will come from Blue Streak, Britain's abortive ballistic missile programme from the 1950s.

The solid fuel rocket sits atop the vehicle, raising the centre of gravity, hence the designers have been forced to widen the track at the rear to lower the roll centre of the car. The rear wheels are therefore out-rigged, but shrouded in double-needle fairings. Another technical challenge is provided by the fact that the fuel consumption changes the weight distribution substantially over the course of a run. One tonne of hydrogen peroxide and half a tonne of jet fuel are expended on each such run, reducing the weight of the 6.5 tonne car to 5 tonnes in 80 seconds. To compensate, moveable winglets will be employed above the wheels to maintain constant wheel loadings.

It's all far more interesting than bovine lactation.

Bloodhound SSC