Only sky

Only sky is what's in this picture (and a little sea). I took it at Westport. Look west from Westport and the sky stretches to Newfoundland.

Only Sky is also the title of a very beautiful record by David Torn; one man, electric guitar and oud, an effects rack and a deep musical sensibility. It's always good to look up.

Books

I've been reading books. Always dangerous.

In The Corporation by Joel Bakan I found ideas like this:

As a psychopathic creature, the corporation can neither recognize nor act upon moral reasons to refrain from harming others. Nothing in its legal makeup limits what it can do to others in pursuit of its selfish ends, and it is compelled to cause harm when the benefits of doing so outweigh the costs.

Joel Bakan is a Professor of Law at University of British Columbia, no ranting hippy. This view is substantiated in detail via a historical review of the emergence of the corporation, an analysis of the legislative framework defining the corporation, and detailed accounts of particular legal cases. Reviews said things like, "...a surprisingly rational and coherent attack on capitalism's most important institution."

Before picking up The Corporation (and alongside books on quite different topics, and again quite different topics) I had been looking at Neoliberalism: A very brief introduction by Manfred B Steger and Ravi K Roy. For the last few decades much of the world has been run in a certain way associated with the names Thatcher and Reagan, Blair and Clinton. The word, "Neoliberalism" denotes an attempt to define the key features of this project. Again, a quotation:

Neoliberal modes of governance encourage the transformation of bureaucratic mentalities into entrepreneurial identities where government workers see themselves no longer as public servants and guardians of a qualitatively defined 'public good' but as self-interested actors responsible to the market and contributing to the monetary success of slimmed-down state enterprises.

So, we convert the instruments of state - health, social services, education, regulatory bodies - into the same sorts of "psychopathic creatures" that dominate the marketplace. They will operate in a landscape defined partly by income and expenditure, exactly like companies; but also partly by "targets" and "Key Performance Indicators", instruments of management put in place with the intention of ensuring they continue to meet their societal purposes (here's a pretty grim account, not at all reassuring of this process in UK higher education). We are apparently confident we can do this in a way that will offset any psychopathic tendencies they might start to display. Good idea?

Cycling in the universe

I went out on my road bike, first time for a year. Heading south down the A77 I did not feel awful, stronger than expected. I kept going. I turned the corner onto the Eaglesham Moor road and discovered a fierce headwind that had previously been behind me. Oh dear. The steepest climb of the outing became even more gruelling.

At the top of the Eaglesham Moor road there's a layby. I stopped there for a minute to recover. A strong, experienced looking cyclist arrived from the west, same as I had, saying, "that was awful!" In principle this is a drab, empty spot but it always seems really beautiful when you've attained it solely by your own efforts, starting from the populous suburbs. On a clear day there is a very open view west with Arran in the distance. It's even more uplifting if you arrive from the east so that the vista towards the coast suddenly opens up after a bit of a climb.

How does one deal with a climb into a headwind, when the unfeasibly slow pace does not seem to justify the pain? Head down, lowest functional gear, stop looking around, keep pedalling. My thoughts turned in, away from the wind. Would a lighter bike help? I never indulged my cro-mo longing but it did provide some raw material for a blog posting. I'm still on the bike I owned then. Its frame is aluminium. Like almost all other chemical elements aluminium was synthesised in nuclear reactions during the life histories of stars. It exists on Earth now because of events that took place in the insides of long-dead stars - BIG stars, more than eight times the mass of the Sun. Our poor little Sun will never see such events but it will see a stage in its life, far in the future, long after it has swollen up until it engulfs the Earth, in which carbon is manufactured in its deep interior. Carbon might be even better for bike frames than the cro-mo alloys, very light, super-strong yet forgiving for the rider. There's lots more carbon lying around than molybdenum - got manufactured in many more stars - but the production of carbon fibre and the manufacturing process mean carbon bikes are even more expensive.

And what's the deal with this stupid wind anyway? Sunlight falls more obliquely on the ground in the polar regions than at the equator, so the air is hotter and the gas pressure greater at low latitudes so air starts moving. Mix in the rotation of the Earth, variable cloud cover, friction with the ground and the shapes of the land masses etc. and before you know it you have a messy, changeable weather system. Another aspect of everyday life that finds its ultimate explanation in Earth's place in the cosmos, exposed to light from the Sun.

In so many ways my bike ride, like all of our existence - pleasures and headwinds! - couldn't be what it is without our place in a huge, old universe.

York

Wallowing in that ineradicable streak of Adult Educator I attended the annual meeting of UALL, the Universities Association for Lifelong Learning. (Of course I'm being a little flippant; I'm currently Vice-Chair of UALL's Scottish wing, SUALL). I heard presentations on topics like older adults learning (how, why do people really learn in their 80s and 90s?); patterns of learning, and indeed life more broadly, in cities; "work-based" learning (which might be a way into work as well for people in work), etc. Some of them were more relevant than others to details of my own work but all had some interesting ingredient. I particularly enjoyed hearing from some of Leeds' Learning Champions, mature students who are happy to act as advocates, to tell their "I did it, so can you" stories to people who might be thinking of study themselves. We have a lot of these stories among our own Access students and I was left wondering if we might start something like our own Learning Champions scheme.

My professional identity has been sliced in two. For half the week the Access programme gets my attention and I'm an adult educationalist. In the other half I'm an astrophysicist, teaching and researching. At the UALL conference I wasn't thinking too much about Astronomy but that changed suddenly and unexpectedly.

The weather was kind: brilliant sunshine, azure skies, but cold air, especially in the low late afternoon Sun. I sat on a bench in the Dean's Park replying to email (eduroam seems to work throughout much of York city centre). Walking along Minster Yard I was already a couple of steps past this plaque when the name "Goodricke" sank in. When the deaf and dumb John Goodricke (1764-86) died at the age of 21 he had already made a lasting mark on Astronomy. People who only ever glance casually at the sky will find the stars unwavering. They might be surprised to learn that many of them vary significantly in brightness. Goodricke made some of the earliest discoveries of such variable stars, in particular the star Algol, in the constellation of Perseus. Every 2.87 days Algol drops to about a third of its normal brightness. It takes a few hours to fade to faintest, stays more or less this faint for a couple of hours, then brightens up again over the next few hours. This is easy to watch, once you know to look for it, and predictions of the times of minimum brightness are available online. Together with his pal Piggott, Goodricke correctly guessed the reason for this regular fading: the eclipse of a bright star by a fainter, orbiting companion. Here's a nice discussion of this famous star, just one more point of light to the casual eye but beautiful in its regular behaviour.

I was jolted out of my adult educator identity into my astronomer identity, a bit like those moments at the end of each episode of Quantum Leap when Sam Beckett finds himself in a different body, in a new time zone. The memories that popped up, however, were from the time when I was neither one thing nor the other but a true hybrid: an adult student, outside the Paisley Coats Observatory many years ago, saying out loud, "that star's really got brighter since we started watching"; a student on the BEd course, training to be a primary school teacher, whose project report described a very cold winter night camping on Rannoch Moor, popping out of the tent every 20 minutes for another Algol brightness estimate. Ah, the were-astronomer days.

Alpha particles

Here's a photograph of a little demonstration cloud chamber:

To the right in the chamber, diagonally across the picture, there's a tungsten welding rod. These rods work better if traces of other substances are added to them and this one has a small amount of thorium oxide. Thorium is a naturally occurring radioactive substance so these welding rods are very slightly radioactive, not enough to endanger the lives of welders - obviously! - but enough to be interesting in the cloud chamber.

Thorium is chemical element number 90. It has chemical symbol Th. The isotope we find in nature is ²³²Th, "thorium-232". From webelements.com we find that its half-life is 14 billion years - it stays radioactive for a long, long time, but at a low level.

Look at the two misty streaks heading left from the welding rod. Each of these is the path of a single alpha particle, a nucleus of the element helium, ejected forcibly from a thorium nucleus when it spontaneously decays. As it travels through the air in the chamber the fast-moving alpha particle knocks electrons out of atoms, leaving a trail of ions behind it. The chamber, cooled well below room temperature, contains alcohol vapour as well as air. Each ion becomes the centre for the formation of a little droplet of liquid alcohol and the path of the alpha particle becomes visible as a string of liquid droplets. The cloud chamber, Nobel-prize winning invention of the Scot CTR Wilson, doesn't quite show us individual electrons and ions but it does let us see where they go and how they move.

Let's do some sums. Alpha-particles emitted in radioactive decay all have more or less the same energy, depending only on which radioactive nucleus we started from. There's a table at this link, telling us that an alpha particle emitted by ²³²Th has an energy of 3.8111 MeV.

The eV - "electron-volt" - is the convenient unit of energy in the subatomic world. We need 14.5 eV of energy to completely liberate an electron from a nitrogen atom and make it into an ion - ionise it; 13.2 eV for an oxygen atom. The average energy of a photon of sunlight is about 2 eV. "M" stands for "mega": one million. So just one of these ²³²Th alpha's will ionise hundreds of thousands of atoms.

(Yes, we call them "alpha's" in a familiar way. Maybe even α's, using the Greek symbol. They're our friends.)

As an α travels away from the nucleus that spawned it, through the air of the laboratory, it loses energy by knocking electrons out of atoms. Each ion created robs the α of roughly 30 eV. How far can it go in air?

The answers to such questions are well known, even available online. From the NIST ASTAR program, available online, we learn that a 4 MeV α stops in a column density of 0.003 grams per square centimetre of air. We need to think about how much material the α meets, and this is best expressed as the amount of material in a cylinder of 1 cm² area. This hypothetical cylinder should include 0.003 grams. If it's very tenuous, like the air we might meet in the stratosphere, the cylinder has to be very long. At sea level where the air is much denser, it will be shorter. But it needs to include 0.003 grams. Air at sea level has a density of just over 0.001 grams per cubic centimetre, so the α will travel (0.003 grams per cm²)÷(0.001 grams per cm³) = 3 cm - slightly over an inch, just as we see in the picture.

In solar flares, ions sometimes get accelerated to energies of MeV and beyond, by strong electric fields, not in radioactive decay. The same ideas apply. How far will they go? How much will they heat up the solar atmosphere in the process? In the cloud chamber we can see much of the relevant physics, even for this remote and exotic application.

Celtic Connections

Celtic Connections is Glasgow's annual, winter festival of "roots music", Scottish and Celtic certainly but also genres like Country and Western that have some kinship, and indigenous musics from across the globe. Most music that still retains some element of "authenticity", according to some criterion or other, can turn up there. I don't enjoy only "clattery, atonal music" so there are always many more appealing gigs than I have time or money for.

My wife and I looked through the 2017 programme together. It's always a pleasure to find musical common ground. Both of us laughed out loud, involuntarily when we saw Olivia Newton-John's name among the headliners. Ms Newton-John started in country music, she's had a huge, starry career in popular music, she'll sell out at Celtic Connections and her audience will be ecstatic. So why did we laugh? Perhaps even the organisers expected some people to laugh when they wrote: "It might seem a startlingly long way from Sandy in Grease to Celtic Connections." Or perhaps the alternative version, "Olivia Neutron-Bomb", hybrid of 1980s headlines, popped up unbidden in both our minds. Pesky neutrons, there's so much to say about them, even before thinking of Ronald Reagan and the French nuclear weapons programme.

Amusement passed and attention moved on. I blogged about the famous photo of the 1927 Solvay Conference. I did not expect Olivia to pop up again so soon but she did. My mind is still slightly blown by the discovery that she is the granddaughter of Max Born, one of the founders of quantum mechanics. Love song pop music bumps up randomly against the fundamental nature of reality.

Here's the Solvay Conference picture again. Born is second from right in the second row, with Niels Bohr on his left-hand side at the end of the row. The Scot CTR Wilson is just to his left in the front row.

Born recognised that matrix algebra lay at the heart of Heisenberg's weird new view of inside the atom. Born was the man who saw how to use the wave in Schrödinger's wave equation to calculate the probability of finding the particle. No more little billiard ball particles ever again, but an elusive cloud of possibility. His contributions were recognised in the 1954 Nobel Prize for Physics.

I've been scouring - well, glancing at - Olivia Newton-John's discography. Can we find traces of fundamental physics? I'm afraid I struggled. Those country songs about home towns and true love, Banks of the Ohio, Take Me Home Country Roads, If You Love Me Met Me Know, there's not much traction there. But here she is singing, Let Me Be There: an impossible request. When the listener carries out that experiment that reveals exactly where Olivia is, there is no way of telling where she will be found. There is a most likely position, and a region around that where she has, say, a 90% chance of being found but we can never say exactly where she will be. "Let me be there" is a plea that might be satisfied, by chance, but there is no agency that can see to it for her; no hidden variables that can be manipulated to her advantage.

"This is nonsense," you say. "If Olivia wants to be in Ohio, or Carradale, or in her lover's arms, of course she either will or won't be." In practical terms this is true. Quantum effects play no role in predicting positions on the scale of everyday life. But if Planck's constant were bigger, we would have to think about these possibilities and they are an essential part of understanding the subatomic world.

I doubt I'll be be there myself - sorry, too far from my musical comfort zone - and I don't expect any of this will trouble very many others in Olivia Newton-John's Celtic Connections audience. But really, if she sings Let me be there, feel free to ask her what her grandfather would think.

From Bern to Solvay

I spent last week at the International Space Science Institute (ISSI), Bern, Switzerland. I was there with a team of scientists aiming to understand better the role of energetic ions in solar flares.

Our team went really well, excellent discussions, progress on our key questions, but by Friday afternoon everybody else had left. I worked for a little bit on the team website before skiving off to become a tourist for a few hours. (Complete aside: let me mention how surprised I was by the etymology of skive. As one of those few thousand words we all had in common in school, and a very important one, I always assumed it was a Scots word; not according to the Oxford English Dictionary).

Albert Einstein lived in Bern for a few years at the very start of the 20th century, famously working as a patent clerk at the same time as puzzling over questions like, "how would the world look to somebody travelling with a beam of light?" A scientific paper he wrote in 1905 earned him the Nobel Prize in Physics and it probably isn't even the most important paper he published that year. The time he spent in Bern represents an extremely important episode in the history of science and it's no surprise that the apartment he lived in is now a tiny museum, the Einsteinhaus.

On Friday afternoon I visited the Einsteinhaus. There are nice displays on his family life, his career, his fame. Among them my eye was caught by a mounted print of the photo at left, showing attendees at the 1927 Solvay conference. It's a very famous photo, showing many of the biggest names in 20th century physics all together at the same meeting. Like most physicists I've seen it often, in various places, and noted for example CTR Wilson, our great Scottish genius of experimental physics, second from right at the front.

In the Einsteinhaus I took some minutes to look again at this picture. It's amusing to see the faces that go with those famous names. Who looks confident, bold, who shy and diffident? At the far left-hand side I was slightly surprised to spot two gentlemen almost side by side whose names are often met together in the textbooks, Messrs Peter Debye and Irving Langmuir. Langmuir is right at the left end of the front row, with a rather natty cane. The moustachioed Debye is peering over Langmuir's right shoulder.

In very hot gases, like those met in the outer layers of the Sun, collisions between atoms are sufficiently violent that they completely remove electrons; ionise the atoms. The constituents of the gas are electrically charged. We call the gas a plasma - a term first used by Langmuir, apparently. Plasma behaves in all sorts of new and interesting ways compared to the ordinary, neutral gas we're surrounded by here at sea level on Earth.

The Debye length is the greatest distance over which an electric field can persist in a plasma - because its constituents are electrically charged, if we try to impose an electric field the charges will just move to short it out. Langmuir waves are something like sound waves but with electric fields playing a central role. Their natural frequency, the plasma frequency, is one of the basic numbers that describe a plasma. The Debye length is another. In the first few pages of any book on plasma physics we meet the names of Langmuir and Debye so it tickled me to find the two of them side by side in the 1927 Solvay Conference picture.

Both were Nobel Prize winners, for Chemistry rather than Physics. Langmuir later became rather notorious for attempts at rain-making. The great German scientist Arnold Sommerfeld was once asked what was his greatest discovery. "Debye," he replied.