Archive for the The Universe and Stuff Category

This Week’s Bridge Problem, No. 236

Posted in The Universe and Stuff with tags , , on October 15, 2012 by telescoper

Rolling Boulders…

Posted in Bad Statistics, The Universe and Stuff with tags , , , , , , , , on October 13, 2012 by telescoper

I’m a bit slow to get started this morning, since I didn’t get home until the wee small hours after a trip to the Royal Astronomical Society yesterday, followed by a pleasantly tipsy dinner at the Athenaeum with the RAS Club. Anyhow, one of the highlights of the meeting was a presentation by Prof. Gerald Roberts from Birkbeck on Marsquakes: evidence from rolled boulder populations, Cerberus Fossae, Mars.  The talk was based on a recent paper of his (unfortunately behind a paywall), which is about trying to reconstruct the origin and behaviour of “Marsquakes” using evidence from the trails made by rolling boulders, dislodged by seismic activity or vulcanism.  Here is a sample picture showing the kind of trails he’s using – the resolution is such that one pixel is only 20cm!

There are enough trails to allow a statistical analysis of their distribution in space and in terms of size (which can be inferred from the width of the trail). I had some questions about the analysis, but I haven’t been able to read the paper in detail yet so I won’t comment on that until I’ve done so, but the thing I remember most from the talk were these remarkable pictures of what a rolling boulder can do on Earth. They were taken after the earthquake in Christchurch, New Zealand, in 2011.

A large boulder was dislodged from the top of the hill behind the house in the second picture. It didn’t just roll, but bounced down the slope (see the large furrow in the first picture; similar bouncing trajectories can be seen in the picture from Mars), smashed straight through the house, exited the other side and came to rest on a road. Yikes.

How many hours per week should a graduate student work?

Posted in Biographical, Education, The Universe and Stuff with tags , on October 11, 2012 by telescoper

Here’s one of those things from Blogland that is flying around the Twittersphere today..

The original post revealed a leaked email  “sent to the entire graduate student body enrolled in the well-regarded astronomy program at Unnamed Academy” containing such gems as this:

We have received some questions about how many hours a graduate student is expected to work.  There is no easy answer, as what matters is your productivity, particularly in the form of good scientific papers.  However, if you informally canvass the faculty (those people for whose jobs you came here to train), most will tell you that they worked 80-100 hours/week in graduate school.  No one told us to work those hours, but we enjoyed what we were doing enough to want to do so.  We were almost always at the office, including at night and on weekends.

This missive has already provoked a number of responses (e.g. here and here), but I couldn’t resist putting in a few comments myself.

The first and most obvious thing is that I don’t think the faculty members mentioned above were telling the truth. It’s by no means a new phenomenon for oldies to pretend that they worked harder than the younger generation. “When I were a lad…”, etc. This is either  form of delusion that accompanies ageing or a kind of one-upmanship designed to create a impose some sort of authority over the junior members of the department.  A supervisor who demands such things of a PhD student is likely to be someone who regards a grad student simply as a form of cheap labour and doesn’t care at all about their development as a researcher or indeed as a human being.

The following sentence gives the game away

No one told us to work those hours, but we enjoyed what we were doing enough to want to do so.

It is clearly intended to mean No one told us, but we’re sure as hell telling you…“.

My advice to a young PhD student would be: if your supervisor tells you to put in 100 hours per week on the project, find another supervisor –  because he/she clearly hasn’t put sufficient thought into the practical feasibility of your project. The fact is if you have to work 100 hours per week to get your work done you must be exceptionally inefficient or working on a stupid project or simply nuts. Or all three.

The email is correct in saying that it’s “productivity” that counts. I’m sure there are many people who can sit at their desks for 11 hours a day without producing anything very much at all. It’s not the hours that matter, but what you do with them. In no way will indulging your outside interests (sporting, cultural, political, or “other”…),   or simply relaxing, detract from your ability to do research. I think such diversions actually improve your work, as well as (of course) your general well-being.

I had plenty of outside interests (including music, sport and nightlife)  and took time out regularly to indulge them. I didn’t – and still don’t – feel any guilt about doing that. I’m not a robot. And neither are you.

In fact, I can think of many times during my graduate studies when I was completely stuck on a problem – to the extent that it was seriously bothering me. On such occasions I learned to take a break. I often found that going for a walk, doing a crossword, or just trying to think about something else for a while, allowed me to return to the problem fresher and with new ideas. I think the brain gets into a rut if you try to make it work in one mode all the time.

But there is an element of truth in the paragraph quoted above. There were indeed many times during my time as a research student – and have been since – that I worked extremely long hours. I wouldn’t say exactly that was because I “enjoyed” it, but that I wanted to know the answer and couldn’t get the problem out of my head.  I’ve stayed up into the early hours of the morning trying to finish a crossword too. Not because I had to, but because I couldn’t put it down unfinished. I know that makes me a saddo in many minds, but I think that’s the sort of obsessiveness and tenacity a researcher needs: becoming so absorbed by the task in hand that you don’t notice the passage of time.

Anyway, as  a research student I certainly didn’t work 80-100 hours per week routinely, although I might have done a few times when things were getting interesting. I think an average working week of 40 hours is perfectly fine for a PhD student, as long as you use that time efficiently and are prepared to step up a gear when motivated to do so.

It’s been a while since I last had a poll, so let’s see if we can generate some statistics on this…

My talk at “The Origins of the Expanding Universe”

Posted in Books, Talks and Reviews, The Universe and Stuff with tags , , , , , , on October 9, 2012 by telescoper

You may recall that I gave a talk recently at a meeting called The Origins of the Expanding Universe in Flagstaff, Arizona. I put the slides up here. Well, the organizers have now put videos of the presentations online so you have the chance to see mine, warts and all.

I was relieved when I saw this on Youtube that the organizers were kind enough to edit out the embarrassing bit at the start when my laptop refused to talk to the data projector and I had to swap to another one. Sorting all that out seemed to take ages, which didn’t help my frame of mind and I was even more nervous than I would have been anyway given that this was my first public appearance after a rather difficult summer. Those are my excuses for what was, frankly, not a particularly good talk. But at least I survived. Better is the end of a thing than the beginning thereof.

A Nobel Book

Posted in Science Politics, The Universe and Stuff with tags , , , , , , , , , on October 8, 2012 by telescoper

The announcement this morning of the 2012 Nobel Prize for Medicine or Physiology reminded me that tomorrow will see the announcement of the 2012 Nobel Prize for Physics. This is due to happen tomorrow morning at 11.45 CET (which I think is 10.45 BST) or thereabouts. It would be unseemly to speculate on the outcome, of course, so that’s what I’ll do.

Although the discovery of a scalar particle at the Large Hadron Collider that may well be the Higgs boson happened only recently, and is yet to be definitively proven to be the Higgs, the smart money has to be on an award relating to that, presumably to Peter Higgs. However, given that the award can go to up to three individuals, who else might earn a share? Gerald Guralnik, Tom Kibble and Carl Richard Hagen came up with the same idea about the same time as Higgs, but all four of them can’t win according to the rules. Answers to that little conundrum on a postcard…

But of course the Prize might go to something else altogether. An interesting bet would be Alain Aspect for his important work on experimental studies of quantum entanglement. Also with an outside chance is Sir Michael Berry for his brilliant work on the Geometric Phase.

That’s by no means an exhaustive list of runners and riders, but I have to get back to business now. I’d be interested to have further nominations via the comments box and will of course be getting an early night ahead of the expected phone call from Stockholm tomorrow morning…

The Week’s Ending

Posted in Biographical, Education, The Universe and Stuff with tags , , on October 6, 2012 by telescoper

A later post than usual for a weekend. I’ve been feeling a bit fragile all day after a very late night last night “playing Bridge” (i.e. drinking and gossiping into the early hours of the morning, with the occasional hand of cards thrown in for good measure). My broadband connection has also been playing up nearly as badly as the connections in my brain, although I don’t think there’s a causal relationship between the two. Anyway, just time for a round-up of, and some reflections on, the events of the past seven days.

This has been the first week of term, so has naturally been extremely busy. I got my first week’s second-year lectures, examples sheets and handouts together last Sunday for a 9am start on Monday morning. There were 104 students on the register, and I was delighted to find that 100 of them actually showed up bright and early for the first session. The lecture wasn’t brilliant unfortunately – I misjudged how many worked examples I could fit into an hour and got a bit rushed as a consequence. Still, at least nobody threw anything at me, and I survived. At the end of the week the students were asked to hand in solutions to some problems, which most of them seem to have done. Unfortunately, however, I neglected to ask for the key to the box in which they are posted before the support staff went home at 5pm, so the scripts are still all in the box. At least that gives me an excuse for not having started to mark them yet.

I gave another lecture this week to the 4-th year Cardiff students taking the Quantum Field Theory lectures from Swansea, to try and fill in a bit of background our lot won’t have learned in other lectures on relativistic quantum mechanics, chiefly the Dirac equation. I really love that sort of stuff, so didn’t mind stepping up to do an impromptu class on it. They seemed to find it reasonably useful, although I went on a bit longer than I should.

Two other events this week in the School were a colloquium by Dr Anupam Mazumdar from Lancaster on Wednesday and a seminar by Prof. Pedro Ferreira from Oxford yesterday (Friday), both of which were related to alternative theories of gravity (i.e. modifications of Einstein’s theory of general relativity). Pedro has co-authored a comprehensive review article on such things if anyone is interested in following up the details. The basic point, however, is that standard cosmology almost all develops from the assumption that gravity and space-time are described by general relativity. That theory is well tested on solar-system scales, but independent tests on the much larger scales involved in cosmology are hard to come by. It’s clearly therefore an important goal to work towards testing alternative theories, as is the case in any scientific discipline.

As well as these specific events there was a steady stream of problems and irritations to do with the teaching timetable: rooms too small, clashes, and so on. This is part of my responsibility as Director of Teaching and Learning in the School of Physics and Astronomy, and I don’t mind telling you that it’s a royal pain in the derrière. However, I think all the bugs have been ironed out and we can hopefully now carry on with a settled teaching programme into the new year.

Looking back on the week I can see so many things I would not long ago have found unbearably stressful, even going to the pub after Friday’s seminar.  Such victories, however insignificant they may seem to others,  have given me the confidence to face the  greater challenges that I know the future has in store.

Lectures by Video

Posted in Education, The Universe and Stuff with tags , , , , on October 2, 2012 by telescoper

I spent a short while this morning sitting in on a lecture from one of our fourth-year modules, on Quantum Field Theory. Nothing obviously remarkable about that, except that the lecture was in fact delivered by Prof. Graham Shore of Swansea University and I was sitting in the School of Physics & Astronomy at Cardiff University with a group of twenty or so Cardiff undergraduates.

This was the first lecture our students have received from Swansea as part of an arrangement to share some teaching. There was a plan to do it last year, but it fell apart owing to technical problems. When I took over as Director of Teaching and Learning earlier this year I was determined to make it work. I have long felt that many of our 4th-year students were losing out on some advanced topics, especially in particle physics, owing to the lack of expertise in that area here. Indeed, the lack of expertise in particle physics here in Cardiff is so extreme that our students have had to put up with being taught by me! Likewise Swansea’s undergraduates have missed out a bit on some topics we do here, especially astrophysics and gravitational physics. This division of labour dates back to the old federal University of Wales where it was decided for strategic reasons not to compete in these two areas of “big science” but to allow Cardiff to do astronomy, astrophysics and gravitational physics and Swansea the particle stuff. It was a sensible decision from a research point of view, but it meant that the two relatively small physics departments here in South Wales could offer their undergraduates more restricted choices of advanced topics  than at bigger universities.

Not for the first time, the web has furnished a solution. After a few technical problems – not entirely sorted out, to be honest – we’ve finally established a video link. The initial setup is temporary, but we will (hopefully by next week) have a permanent, high quality videoconferencing suite for future use. It will probably take some time for lecturers and students on both sides to get used to it, but sitting in this morning I found it more than satisfactory from the point of view of audibility and legibility. The only problem really is that the static camera shot makes it a bit claustrophobic. I’m not sure whether there’s a way around that without spending a fortune on multiple cameras.

Anyway, to mark this historic occasion I thought I post another video lecture on Quantum Field Theory just to give you a flavour of the content and the experience. This is by David Tong of Cambridge University as seen in a lecture recorded by the Perimeter Institute in Canada.

 

Anyway, in the spirit of openness, and because I couldn’t stay for the whole session,  I’d be interested to hear what any Cardiff students thought of the experience either in private or through the comments box..

Cosmology Webcasts Coming Up…

Posted in The Universe and Stuff with tags , , , , on September 29, 2012 by telescoper

Courtesy of freelance science writer Bruce Lieberman, whom I met briefly at the recent “Origin of the Expansion of the Universe” meeting in Flagstaff, AZ,  here’s a plug for two live webcasts on topical topics that are coming up in the next couple of weeks. On behalf of the Kavli Foundation, Bruce will be interviewing astronomers about the new Hubble XDF image (Oct. 4) and the new Dark Energy Survey camera, which just saw First Light (Oct. 11).

Live Q&A and Webcast: What Does Hubble’s Deepest Image of the Universe Reveal?

Click on the above heading for  direct link to webcast.

October 4, 11-11:30 am PDT (18-18:30 GMT; 19-19:30 BST)

Using data from the Hubble Space Telescope, a multi-national team of astronomers recently released our deepest-ever image of the
universe. Pascal Oesch, a Hubble Fellow at the University of California at Santa Cruz, and Michele Trenti, a researcher at the Kavli Institute for Cosmology, Cambridge at the University of Cambridge in the U.K., answer your questions about how the image was created and what it reveals about the early universe.

Viewers may submit questions to the two Hubble researchers via Twitter using #KavliAstro or email to info@kavlifoundation.org.

Live Q&A and Webcast: Can a New Camera Unravel the Nature of Dark Energy?

Click on the above heading for  direct link to webcast.

October 11, 9-9:30 am PDT (16-16:30 GMT; 17-17:30 BST)

Scientists have great expectations for the newly operational Dark Energy Camera, which may significantly advance our understanding of the mysterious force expanding the universe at an ever accelerating rate. Fermilab scientists Brenna Flaugher, project manager for the Dark Energy Camera, and Joshua Frieman, director of the Dark Energy Survey, answer your questions about the camera and what it’s expected to reveal.

Viewers may submit questions via Twitter using #KavliAstro or email to info@kavlifoundation.org.

Extremely Deep Space

Posted in The Universe and Stuff with tags , , , on September 27, 2012 by telescoper

There’s been a lot of media coverage of this image, taken using the Hubble Space Telescope using an exposure time of 2 million seconds (aproximately 23 days), including a nice feature article on the BBC Website to which I refer you for more explanation, so I’ll keep this post brief. Suffice to say that the Hubble eXtreme Deep Field (XDF) is the deepest image of the sky ever obtained and it reveals the faintest and most distant galaxies ever seen, showing some galaxies as they were over 13 billion years ago. It’s also very very pretty…

And if the overwhelming scale of the Universe revealed by this picture makes you feel worthless and insignificant, just remember that things could have been much worse. You might have been Nick Clegg.

A (Physics) Problem from the Past

Posted in Cute Problems, Education, The Universe and Stuff with tags , , , , , on September 25, 2012 by telescoper

I’ve been preparing material for my new 2nd year lecture course module The Physics of Fields and Flows, which starts next week. The idea of this is to put together some material on electromagnetism and fluid mechanics in a way that illustrates the connections between them as well as developing proficiency in the mathematics that underpins them, namely vector calculus. Anyway, in the course of putting together the notes and exercises it occurred to me to have a look at the stuff I was given when I was in the 2nd year at university, way back in 1983-4. When I opened the file I found this problem which caused me a great deal of trouble when I tried to do it all those years ago. It’s from an old Cambridge Part IB Advanced Physics paper. See what you can make of it..

(You can click on the image to make it larger…)