Friday, 28 July 2017

Back to their future


It was about two years ago when my enthusiasm for very amateur astronomy got me into trouble (of sorts). Not that I knew it at the time, one often doesn’t. Hindsight is 20:20 they say.
A 360º time-lapse movie of the sky over Blean (north Kent, UK) taken with the skycam at the Beacon Observatory at the University of Kent. The mast on the right is the observatory’s weather station. Despite the local light pollution, it’s possible to make out several constellations as well as the Milky Way (– our Earth-bound view of our own Galaxy; in September, when this sequence was captured, the galactic centre would have been just out of shot). Read on to see how this fits into the post.
I can’t remember a time when the night sky didn’t fascinated me; in some ways one might say that it was my entry point into science. Had it been a subject available at my school I would have chosen it. As it was I had to wait until I was allowed to drive my parents’ car from our village to the nearest large town – in which there was a library running adult education classes in observational astronomy. I’ll never forget the first time, using my small [1] and necessarily inexpensive telescope, I saw the shadows of mountains on the Moon, the phases of Venus, ‘bulges’ on the side of Saturn created by its unresolved rings, and watched the motion of the four Galilean moon of Jupiter. There’s no going back after that. I even tried my hand at astrophotography: in classic ‘Heath-Robinson’ style – a ‘bricolage’ as they might say in France – I built a frame from scraps of wood to hold the telescope and my soviet-made 35 mm camera atop a tripod. It never did work; I couldn’t get the focal distances right. As the years passed by I spent less and less time outside gazing upwards: there were so many other things to focus on. The underlying fascination, however, never went away; more recently it has begun to re-surface – hence this post.
By the age of 13 I was using a notebook to make sketches and describe what I observed – here, what I later learnt were haloes around the Moon caused by high-altitude ice crystals.
A few months before my ‘retirement’ I was given on loan a somewhat larger and more sophisticated telescope [2]. It had been donated to a primary school, where no-one knew how to use it or had the time to find out, and for which no-one could foresee a practicable use given the young age of the pupils. The whole thing had just been re-discovered in a series of boxes in a cupboard somewhere. The idea was that I figure out how to run it and begin to explore what the school might do with it in the longer term. I’m still a long way from completing my task, but I have slowly mastered the basics. It’s too cumbersome to transport it away from my built-up and excessively illuminated neighbourhood, so I rely on the few shadowy spots on my front drive and rear garden for observing sites – and rejoice on those rare occasions when the nearest street lights fail. Thus, the motivation to set it up more fully each time it emerges from my garage is not strong. That notwithstanding, I am beginning to have a lot of fun with it. There’s an inexhaustible list of things to look at, and key goals remaining like viewing our near-neighbour galaxy, Andromeda. However, for now it remains a work in progress, and moves forward at the rate I wish to lose sleep on clear nights. 
My early attempts at photographing what I was looking at using my smartphone were far from impressive, although it was just about doable. However, things have begun to improve considerably now that I have invested in a simple clamp that attaches to the telescope’s eyepiece and holds the ‘phone in place. On the left is, self-evidently, my image of the Moon taken using a green filter; the crater rims near the day/night terminator when the Sun is low in the lunar sky are picked out quite nicely. (With a bit of trigonometry, the shadows provide a means of estimating the height of the mountain ranges; e.g. here.) Jupiter has been easily visible in the months leading to this post as the central image, taken directly using my ‘phone, attests. However, train the telescope onto it and the spot becomes a disk and the four so-called Galilean moons may be seen. I need to go back to this and try again with a suitable colour filter: the moons won’t then be seen, but the equatorial rings on Jupiter – gloriously visible with the eye through the telescope – might emerge in an image.

Now we reach the ‘indiscretion’ with which I began. On a return visit to my old department a colleague, Dirk Froebrich, an extremely talented astronomer/astrophysicist with an interest in star formation, reminded me that I had once asked if I could use the telescope [3] then being installed and commissioned on the edge of campus. He gave me the opportunity of being trained in its operation so that I might help to run their science programme when the core team were unavailable. Apparently, there was a period in June when that situation would arise due to conferences, holidays and trips to use really seriously impressive international observatories (e.g. here). I had no real conception of what I was letting myself in for, but said “yes please” nonetheless.
The telescope and its dome at the time I first volunteered. In the few months since then some additional equipment has been installed.
Apart from anything else, I was attracted by the thought that this would form a part of their ‘citizen science’ programme: school groups, amateur astronomy clubs [4] and their like could enlist to look through the data being collected and thereby perhaps contribute to new discoveries. It sounded genuinely exciting, and still does. The essence of the project, as I understand it in my amateurish way, is to measure the light coming from young stars in some of the star-forming regions of our galaxy. Their timeline starts with the emergence of higher density regions within one of the huge dust/gas clouds that exist; this might have been initiated by the effects of light from nearby stars perhaps. Slowly, these swirling masses begin to pull themselves together under the effect of their own gravity until each has a dense central region surrounded by more dust/gas which is attracted inwards under gravity. Each of these entities is rotating: faster now, because that’s what happens when the diameter decreases – think of an ice skater speeding up as their arms are drawn in to their body. Eventually, the central region may become massive and dense enough for nuclear fusion to begin; a star is born. If smaller regions begin to coalesce in the surrounding disk of dust, its accretion disk, then we may see the development of planets, asteroids etc. Unless, that is, the outward pressure of the light and other emissions from this new star overcomes its gravitational attraction and thereby ‘blows’ the dust away. (There’s quite a narrow window, cosmologically speaking, for planetary formation to begin it seems: unless it’s underway within a few millions years the star will indeed blow the dust in its accretion disk away into the
surrounding galaxy. I have adapted an artist’s impression, shown here.) Now, our young stars don’t collect additional matter from the surrounding disk at a uniform rate it seems. A given star may have periods when its brightness increases quite significantly because the rate at which it is accreting new matter from the surrounding disk has increased markedly. There are theoretical models for all this, but a lack of data. This is where the citizen science project comes in. Light curves are very carefully measured and those measurements repeated over an extended period – every cloud-free night for which they are above the horizon in fact – and a hoped-for army of interested volunteers seek out the tell-tale signs of a sudden change in brightness.

I spent most of a night having the necessary software loaded onto my laptop and taking copious notes as I watched over Dirk’s expert shoulders, and another night with him carefully watching me, driving-instructor-like. Then came the fearful part: running the show myself from my laptop at home. I spent my professional life as a scientist using very expensive, often unique, pieces of equipment in pursuit of new knowledge (e.g. in this earlier post). But, perhaps because this is not my area of expertise or experience, finding myself in sole charge of this £100,000+ observatory for a night felt peculiarly daunting - indeed, downright stressful. Thankully, in the short intervening period I have made mistakes, but damaged nothing. Despite what some might consider the foolishness of actually volunteering to lose sleep, I have continued to learn, which is of course what I wanted to do (- alongside making a positive contribution).
There are a lot of windows to monitor, so I connected my small laptop to my home PC’s screen. On a second, older laptop I had radar images showing cloud-cover over my part of the country – that way I had at least an hour’s warning of approaching poor weather, which gave me time safely to close everything up.
‘The proof of the pudding is in the eating’ as the old saying has it. Shown below are the four images associated with my first full night of observation. They are VRI (i.e. individual colour filtered images, later combined) composites of IC1396A, IC5070, MWSC3274 and NGC7129, about 15min integration in each filter. Each is a region of the nearby galaxy in which star formation is occurring; the dust/gas clouds are clearly visible (e.g. top left). The most distant region is approximately 3300 light years away; we’re therefore photographing and measuring it as it was when Tutankhamen died, the first books were being produced in China and a little before the time of Moses. I was looking back in time from a vantage point which may represent their future.



Footnotes:
[1] A refractor with an aperture of about 30 mm at a guess.
[2] A 102 mm, Maksutov-Cassegrain reflector on a motorised equatorial mount, along with an impressive selection of eyepieces and filters.
[3] This is a beautiful beast: a computer-driven reflector with a mirror aperture of 432 mm (i.e. almost 20 times the mirror area of my borrowed telescope, and of far higher optical quality) and with a 16M pixel cooled CCD camera; further details here. The whole thing sits elegantly within its bespoke observatory dome (also driven remotely via computer), together with its own weather station etc.
[4] Perhaps like the club I visited recently, Ashford Astronomical Society: lovely people, full of enthusiasm and experience – highly recommended. I was invited by a graduate of my old department, Emma, who is a leading member there; she and her husband were jointly, and expertly, giving that evening’s talk.



Saturday, 22 July 2017

Radiation in my living room



The University of the Third Age, U3A, was one of several positive discoveries made after I ‘retired’ as an academic and research scientist. It has, for instance, given me the opportunity finally to indulge in more creative writing – within a small group in which, comfortingly, I’m not the only person with a STEM* background. Some of the early-stage output from this endeavour is featured in a previous post (here). The other ongoing need in my life transcends the move from salaried employment to ‘going freelance’: trying to communicate science and my love for it to lay audiences. Although I’d been doing as much of this as I could fit in prior to retirement (e.g. see here or here or in umpteen other posts on this blog) and ad hoc invitations to do this have continued, I felt the need to go beyond one-off short talks. Again, the local branch of the U3A has provided a useful framework. And so it was that, last Autumn – my first year as a member – I opened my living room to a small group of brave souls who’d each paid £3 per session (to the U3A) in order to hear a complete stranger talk about glass. I had three two-hour sessions scheduled, so plenty of scope for peppering the science into a swathe of images and artefacts, art and history. The feedback was really positive, and word evidently spread that there’s more to glass than meets the eye (!) because my re-run of the course this coming autumn has far outgrown my living room and we are being moved to a larger venue in the city. This is hugely gratifying, but more importantly it helped to persuade me that my approach to presenting science in this context was broadly OK. However, talking about glass is, for me, an ‘easy’ thing – it can be harder to stop. I set myself a new challenge.
The opening slide: ready to welcome my brave audience.
One of the things I perhaps ought to take on, or so I told myself, perhaps naïvely, is the use of my training and experience in trying to demystify potentially more contentious aspects of the physical sciences … like radiation for example. It’s a topic I’d introduced to many Physics students over the years, so I had a bit of material to work with. However, the more I thought about it the more of that material I discarded. What was needed, I reasoned, was about an hour’s worth of material which I could spread over 90+ minutes to allow for questions and audience-led detours. The material needed to address the basic requirements of explaining just enough of the science and the terminology for everyone then to make sense of my attempt to introduce a more open-minded perspective than one often sees in the media. In the end I spent goodness knows how many hours researching and preparing new material that I thought might better do the job. In all this it was important to keep the talk grounded in contexts that one might readily appreciate: medical uses of radiation, radiation from the ground below and the sky above, nuclear power and the accidents we’d all have heard about, and so on. Part of this grounding required that we did more than stare at slides; thankfully, I have a Geiger counter on loan from my old department and managed to borrow a set of radioactive minerals from its hugely successful schools outreach team (here, run by a wonderful ex PhD student in my former research group); that would get us started.

The U3A run an annual series of ‘Summer Specials’: essentially taster sessions prior to members selecting what they might like to register for in the main programme, which starts each year in the Autumn. They also allow one to try out ideas for possible new courses, and this therefore provided an ideal vehicle for me. This is what I proposed:
Radiation: beneficial, benign and bad
Radiation, in its many guises, has been a ‘hot topic’ for more than 70 years and a matter of considerable interest of over a century – but how much do we know about it? In this taster session, we’ll take a look at its origins and effects – beneficial, benign and bad – from a scientific perspective. There ought to be no need for a formal science background beyond school-level, and questions will always be welcomed should you need to brush up on something. There will be a little radioactive material used within the session, but nothing that will represent a safety concern for any of us.
The registration list filled within a day or two, and a list of reserves began to form. There is evidently an appetite for such topics; so far, so good.

In the event, I found I had more than enough material for an hour’s worth of my talking. This was a good thing in the sense that it allowed all the space required for what turned out to be a large number of challenging, high-quality questions that emerged as we went through. The downside is that we had less time for connected discussion at the end, but addressing the questions as they arose was definitely of more importance. Indeed, for me, getting good questions is one of the best forms of immediate feedback.
What did we cover in the end?
After introducing ourselves and grabbing a drink and a biscuit or two, we spent a few minutes on the 92 naturally occurring elements and their 1000+ isotopes, and in establishing the prevalence of radioactive isotopes in particular. Next, an overview of the principal forms of ionising radiation and how one might tell which is which; then, how they can be detected using a Geiger counter, and what sort of units we measure them in (the Becquerel, Bq, and the Seivert, Sv, in our case). The final bit of scientific background covered the meaning of the half-life as well as illustrating the concept of the decay chain. No equations saw the light of day – reflecting an important lesson I learned long ago. All-in-all, with questions, we spent about half our time on the basic science before moving on to consider the bad, the benign and the beneficial.
I chose to reverse the order of the aspects of radiation drafted into my purposefully tantalising title: ‘bad’ is, in a very real sense, the easiest to cover – it is, well … bad.
‘Benign’ became, in practice, ‘unavoidable’: we looked at radiation coming from beneath our feet, e.g. from the granite beneath much of the UK’s West Country, and from space; we went on consider the raised levels experienced when flying and then to think through the consequences of the phrase “we are what we eat” in terms of radioactivity within our bodies. This was a good point at which to fire up the Geiger counter to get a sense of the natural background and to examine my borrowed collection of minerals. (The latter came with a thin sheet of lead in a plastic bag and the lid from a tin can – very useful tools in determining what sort of radiation our small lumps of rock were emitting.)
Our final topic came under the heading of ‘beneficial’, and here we looked at medical diagnostics and radiotherapy, at the formation of helium as a product of radioactive decay events within the Earth and at useful aspects of radioactivity such as carbon-14 dating within archaeology. We also considered the nett benefit of having radioactive events within the Earth since they help to heat the interior of the planet and thereby maintain our molten core: without this we’d not have a magnetic field to shield us from the solar wind, and we’d then suffer far, far more radiation from the Sun.

As I’ve said already, a constant theme was always to think in terms of perspective – the balance of risks. I wanted us to leave the session with an appreciation of what radiation is, where it originates, how much of it we encounter and what it does. My hope was/is that the group would thereby be better equipped – one might even say empowered – to engage with current and future debates. Reactions on the day exceeded all my expectations, and what people have kindly said in various emails since then has been truly humbling. One person made a very positive suggestion for improvement which I’ll definitely adopt. I doubt I shall ever forget the two people who, quite separately, said that had they been taught science like that when they were at school their later choices might have been very different. It doesn’t get much better than that.
My parting slide, philosophically tongue-in-cheek, is shown here. We could have spent an entire session exploring these three points alone – and perhaps one day we shall – but we ended our two hours together with the suggestion that they be mulled over. As it turned out, I was motivated to post a brief reflection on the middle one in the week after my U3A talk: here, should you wish to read it.

* STEM – Science, Technology, Engineering and Mathematics; sometimes an additional ‘M’ is added in order to include the Medical sciences.



Wednesday, 12 July 2017

“Science is always wrong”


All the while I was doing it I would get quizzical, sometimes incredulous looks and comments from a sizable fraction of my academic colleagues. Why, they would ask, do I fight to stay closely involved when, in my position – whatever that was I never did fully understand, I could take my pick? ‘They needed my experience elsewhere’ where I would, apparently, ‘get a better shot at picking up research students’ … and so on and so forth. It wasn’t that dissimilar to the internationally well-known and highly respected senior colleague at a previous place of work informing me that I must be mad to leave a fast-track* career there for a junior academic post at an obscure provincial university. Their snippets of advice weren’t a million miles away from so many others I had heard before and have politely listened to since, all of which I am prepared to believe were well-meaning, and many of which may even have been right. However, sometimes no amount of dissuasion will ever be enough.

I helped to design our Foundation Year in Physics (which currently looks like this). It was a time of weak student recruitment and there’s no doubt that this motivated my head of department’s decision to task me and a couple of colleagues with the job. School-leavers with the ‘wrong’ qualifications to enter a Physics degree by conventional routes might change direction or make up for past under-performance by taking what was, in essence, a pre-degree programme of study. Result: more students going into Year 1 of our mainstream undergraduate course. Despite an initially reluctant involvement, I soon came to recognise that this had the potential to offer a ‘second chance’ to people who might need it. Goodness knows I’ve benefited from many of those in my time. Through more than two decades between its formation and my retirement, typically teaching over a quarter of the course to cohorts of up to 70 in number, I never found a group of students more worthy of my investment than were these ‘Year 0’ students. It is no surprise then that most of the innovations I experimented with were introduced in the hope of benefiting them – and thereafter the other groups I taught; I wrote about some of this in a couple of earlier post, here and here. What does this have to do with the title (which, by the way, is extracted from a longer quotation by George Bernard Shaw, see here)?
Read on …

One of the challenges was to persuade students who might regard themselves as ‘failures’ in one sense or another that they had something to contribute. An excellent route turned out to be the use of film/TV/computer game clips and other mass-media as a way into discussing their respective physics content, but another was for me to light a fuse by making an ostensibly outrageous comment – like the one in my title – and watching them defend their chosen subject. Eventually, we’d meander to the point at which most would recognise the kernel of truth in the proposition: history tells us that science is indeed always ‘wrong’. Let’s take one obvious example: the intellectual giant Isaac Newton gave us many elegant descriptions of the physical universe around us and no school textbook on physics is complete without the equations derived from his work. His research on light and colour, for instance, out-lasted the other descriptions available and still holds sway (see my post here to learn more). His description of the effects of gravity, although supreme for more than three centuries and still quite effective in most everyday circumstances, eventually gave way to Einstein’s work on the General Theory of Relativity. In other words, put crudely, Newton and the science associated with him was proved wrong in this regard. ‘Science’ was wrong and needed to be revised. The scientific knowledge we have today will be in need of revision tomorrow. It’s a humbling thought for us scientists – and we fail to take it on board at our peril. There is however a postscript to this line of reasoning. Whilst the results of scientific endeavour are always subject to change over time, it remains the case that that they give us the best insight into the workings of the physical world that we have at a given stage of history. We would have been fools to ignore Newton’s work, and thereby miss all the opportunities for advancement it afford us, on the off-chance that an Einstein was around the corner. We need also to keep in mind that science is more than its results: it’s a methodology, a way of asking questions and testing the limits to our understanding of the material world that is less susceptible to the vagaries of the human mind than some other means of inquiry.

My own early-stage career, as a graduate PhD student in the 1970s, put me in the position of demonstrating that one set of theories was inadequate and that an alternate was required. It was a scary thing to do at the time. Analogous thresholds have been crossed by the excellent former members of my research team from the mid-‘80s onward. However, there is only one true test of the commitment of an individual scientist to the principle of humility outlined above: what happens when one of their own pet theories or shiny experimental results are shown to be in need of revision … or replacement.

Now we reach the impetus behind my drafting of this post. A few days ago I received an email from a member of a German-Canadian research team describing in some detail why their recent data might require that a piece of work I was involved with over two decades ago probably needs to be re-interpreted. The email to me was a kindness – they could simply have written to the editor of the appropriate scientific journal and immediately lodged their comment in print; they wanted instead to see whether, on behalf of my co-authors of the time, I might like to say something first. I wrote back immediately. I shared with them the impracticality of pulling together the people and raw data of more than 20 years ago to undertake a re-analysis in light of this new information. I’m also pleased that I can say that I was able to commend and thank them for their work; I reassured them I saw this as science gaining benefit from their careful review.

Phew:
https://goo.gl/images/5N7Juf

* His words, not mine: I was never ‘fast-tracked’ through anything as far as I am aware, nor would I wish to be.