I’m recently back from my mammoth trip through Asia (though in fact I’m up in Edinburgh as I write this, visiting as a fellow of the Higgs Centre For Theoretical Physics).
I’ve already written a little about the middle week of my voyage, observing at the James Clerk Maxwell Telescope, and I hope to get back to that soon — at least to post some pictures of and from Mauna Kea. But even more than telescopes, or mountains, or spectacular vistas, I seemed to have spent much of the trip thinking about and eating food. (Even at the telescope, food was important — and the chefs at Halu Pohaku do some amazing things for us sleep-deprived astronomers, though I was too tired to record it except as a vague memory.) But down at sea level, I ate some amazing meals.
When I first arrived in Taipei, my old colleague Proty Wu picked me up at the airport, and took me to meet my fellow speakers and other Taiwanese astronomers at the amazing Din Tai Fung, a world-famous chain of dumpling restaurants. (There are branches in North America but alas none in the UK.) As a scientist, I particularly appreciated the clean room they use to prepare the dumplings to their exacting standards:
Later in the week, a few of us went to a branch of another famous Taipei-based chain, Shin Yeh, for a somewhat traditional Taiwanese restaurant meal. It was amazing, and I wish I could remember some of the specifics. Alas, I’ve only recorded the aftermath:
From Taipei, I was off to Hawaii. Before and after my observing trip, I spent a few days in Honolulu, where I managed to find a nice plate of sushi at Doraku — good, but not too much better than I’ve had in London or New York, despite the proximity to Japan.
From Hawaii, I had to fly back for a transfer in Taipei, where I was happy to find plenty more dumplings (as well as pleasantly sweet Taiwanese pineapple cake). Certainly some of the best airport food I’ve had (for the record, my other favourites are sausages in Munich, and sushi at the Ebisu counter at San Francisco):
From there, my last stop was 40 hours in Beijing. Much more to say about that visit, but the culinary part of the trip had a couple of highlights. After a morning spent wandering around the Forbidden City (aka the Palace Museum), I was getting tired and hungry. I tried to find Tian Di Yi Jia, supposedly “An Incredible Imperial-Style Restaurant”. Alas, some combination of not having a website, not having Roman-lettered signs, and the likelihood that it had closed down meant an hour’s wandering Beijing’s streets was in vain. Instead, I ended up at this hole in the wall: And was very happy indeed, in particular with the amazing slithery, tangy eggplant: That night, I ended up at The Grandma’s, an outpost of yet another chain, seemingly a different chain than Grandma’s Kitchen, which apparently serves American food. Definitely not American food. Note especially the “thousand-year egg” at left (I was happy to see from wikipedia that the idea they’re cured in horse urine is only a myth!):
It was a very tasty trip. I think there was science, too.
After a couple of days of lousy weather, the sky cleared up and dried out Wednesday. Eventually, we got down to τ<0.08 — not quite the best possible conditions, but good enough for almost anything we might want to do. We started out slightly worse than that, but that meant we got to observe more interesting things: nearby bright, big galaxies. Unfortunately, a galaxy that is bright and big in visible light is still just a blob in the submillimetre (submm). Our first one was NGC 3034, aka M82, exciting for two reasons. First, it’s the prototypical starburst galaxy, a galaxy undergoing a rapid period of star formation, gobbling up gas and dust and turning them into stars, which in turn heat up the remaining dust, making the galaxy glow brightly in the infrared and submm. Second, M82 is the home of a recent supernova explosion, the nearest one since 2004, and the nearest one of the particularly important type Ia since 1972. And it was first discovered by students at University College London, right across town.
So, I am sure that you are very excited to see a beautiful picture of the galaxy, at right. The elongated blob in the center isn’t even the whole galaxy: that’s the bright nucleus glowing from the concentration of star formation there. I think — and my proper observational-astronomer friends will correct me if I’m wrong — that some of the dark fuzz around the nucleus is really part of the galaxy, which would take up most of this picture, about 15 arc minutes from top to bottom.
After M82, we observed another nearby galaxy, the somewhat less famous NGC 4559, and then conditions improved enough that we could do observations as part of the SCUBA-2 Cosmology Legacy Survey (CLS), which is officially why I’m here. But that’s a lot less fun, as it’s just observing more or less blank patches, again and again, building up a deep submm survey of large areas of sky (where for these purposes, “large” just means about 35 square degrees, out of about 41,000 on the whole sky). We repeat each small patch dozens of times, adding them up and building up pictures so dense with galaxies that they are said to be “confusion limited” — the main source of noise is just the population of galaxies themselves, individually too faint to see, but contributing to the infrared background light everywhere we look (this depends on both the wavelength of the light and the resolution of the telescope — that is, the size of the smallest object that you can make out.).
For the rest of the night, through until dawn, we kept on observing the CLS fields, and have started back onto them today, in even better conditions than yesterday.
So far, I’ve been pleasantly surprised about life at 14,000 feet: there is definitely less oxygen than down at sea level (or even than Hale Pohaku at 9,000 feet where I sleep and spend the days), but I’ve been spared the worse symptoms of altitude sickness. And jet-lag, combined with strong and good coffee provided by the excellent Telescope System Specialist (TSS) has meant that staying up through until 7 or 8am hasn’t been too bad. (On the other hand, re-reading this post leaves the impression that my ability to string a sentence together has been somewhat impaired by the lack of sleep and oxygen…)
In fact, the TSS is really the one doing — quite literally — all of the work here. Because we are observing as part of the JCMT Legacy Survey, there’s nothing for the “observer” (i.e., me) to do. Later on, the survey team will collate the data that have been gathered and make the final images and catalogs, but that’s a slow and painstaking process, not one that happens on the night the data are taken. And taking the data is such a complicated task that only the Specialist really has the expertise to do it. He keeps me informed of what’s going on, but I don’t really get much of a say in what happens.
You may ask why someone spends the money to send us astronomer/observers across an ocean or two to stay up at night, drink coffee, and not really do any science. Gift-horses aside, so do I.
But it certainly is a gift and a privilege to be here:
I am sitting in the control room of the James Clerk Maxwell Telescope (JCMT), 14,000 feet up Mauna Kea, on Hawaii’s Big Island. I’m here to do observations for the SCUBA-2 Cosmology Legacy Survey (CLS).
I’m not really an observer — this is really my first time at a full-sized, modern telescope. But much of JCMT’s observing time is taken up with a series of so-called Legacy Surveys (JLS) — large projects, observing large amounts of sky or large numbers of stars or galaxies.
JCMT is a submillimeter telescope: it detects light with wavelength at or just below one millimeter. This is a difficult regime for astronomy: the atmosphere itself glows very strongly in the infrared, mostly because of water vapour. That’s why I’m sitting at the cold and dry top of an active volcano (albeit one that hasn’t erupted in thousands of years).
Unfortunately, “cold and dry” doesn’t mean there is no precipitation. Here is yesterday’s view, from JCMT over to the CSO telescope:
This is Hawaii, not Hoth, or even Antarctica.
Tonight seems more promising: we measure the overall quality as an optical depth, denoted by the symbol τ, essentially the probability that a photon you care out will get scattered by the atmosphere before it reaches your telescope. The JLS survey overall requires τ<0.2, and the CLS that I’m actually here for needs even better conditions, τ<0.10. So far we’re just above 0.20 — good enough for some projects, but not the JLS. I’m up here with a JCMT Telescope System Specialist — who actually knows how to run the telescope — and he’s been calibrating the instrument, observing a few sources, and we’re waiting for the optical depth to dip into the JLS band. If that happens, we can fire up SCUBA-2, the instrument (camera) that records the light from the sky. SCUBA-2 uses bolometers (like HFI on Planck), very sensitive thermometers cooled down to superconducting temperatures.
Later this week, I’ll try to talk about why these are called “Legacy” surveys — and why that’s bad news.
Some time last year, Physics World magazine asked some of us to record videos discussing scientific topics in 100 seconds. Among others, I made one on cosmic inflation and another on what scientists can gain from blogging, which for some reason has just been posted to YouTube, and then tweeted about by FQXi (without which I would have forgotten the whole thing). There are a few other videos of me, although it turns out that there are lots of people called “Andrew Jaffe” on YouTube.
I’m posting this not (only) for the usual purposes of self-aggrandizement, but to force — or at least encourage — myself to actually do some more of that blogging which I claim is a good thing for us scientists. With any luck, you’ll be able to read about my experiences teaching last term, and the trip I’m about to take to observe at a telescope (a proper one, at the top of a high mountain, with a really big mirror).
[On a much more entertaining note, here’s a song from a former Imperial undergraduate recounting “A Brief History of the Universe”. Give it a listen!]
Nearly a decade ago, blogging was young, and its place in the academic world wasn’t clear. Back in 2005, I wrote about an anonymous article in the Chronicle of Higher Education, a so-called “advice” column admonishing academic job seekers to avoid blogging, mostly because it let the hiring committee find out things that had nothing whatever to do with their academic job, and reject them on those (inappropriate) grounds.
I thought things had changed. Many academics have blogs, and indeed many institutions encourage it (here at Imperial, there’s a College-wide list of blogs written by people at all levels, and I’ve helped teach a course on blogging for young academics). More generally, outreach has become an important component of academic life (that is, it’s at least necessary to pay it lip service when applying for funding or promotions) and blogging is usually seen as a useful way to reach a wide audience outside of one’s field.
So I was distressed to see the lament — from an academic blogger — “Want an academic job? Hold your tongue”. Things haven’t changed as much as I thought:
… [A senior academic said that] the blog, while it was to be commended for its forthright tone, was so informal and laced with profanity that the professor could not help but hold the blog against the potential faculty member…. It was the consensus that aspiring young scientists should steer clear of such activities.
Depending on the content of the blog in question, this seems somewhere between a disregard for academic freedom and a judgment of the candidate on completely irrelevant grounds. Of course, it is natural to want the personalities of our colleagues to mesh well with our own, and almost impossible to completely ignore supposedly extraneous information. But we are hiring for academic jobs, and what should matter are research and teaching ability.
Of course, I’ve been lucky: I already had a permanent job when I started blogging, and I work in the UK system which doesn’t have a tenure review process. And I admit this blog has steered clear of truly controversial topics (depending on what you think of Bayesian probability, at least).
This year, there have been a few changes to the structure of the course — although not as much to the content as I might have liked (“if it ain’t broke, don’t fix it”, although I’d still love to use more of the elegant Dirac notation and perhaps discuss quantum information a bit more). We’ve moved some of the material to the first year, so the students should already come into the course with at least some exposure to the famous Schrödinger Equation which describes the evolution of the quantum wave function. But of course all lecturers treat this material slightly differently, so I’ve tried to revisit some of that material in my own language, although perhaps a bit too quickly.
Perhaps more importantly, we’ve also changed the tutorial system. We used to attempt an imperfect rendition of the Oxbridge small-group tutorial system, but we’ve moved to something with larger groups and (we hope) a more consistent presentation of the material. We’re only on the second term with this new system, so the jury is still out, both in terms of the students’ reactions, and our own. Perhaps surprisingly, they do like the fact that there is more assessed (i.e., explicitly graded, counting towards the final mark in the course) material — coming from the US system, I would like to see yet more of this, while those brought up on the UK system prefer the final exam to carry most (ideally all!) the weight.
So far I’ve given three lectures, including a last-minute swap yesterday. The first lecture — mostly content-free — went pretty well, but I’m not too happy with my performance on the last two: I’ve made a mistake in each of the last two lectures. I’ve heard people say that the students don’t mind a few (corrected) mistakes; it humanises the teachers. But I suspect that the students would, on the whole, prefer less-human, more perfect, lecturing…
Yesterday, we were talking about a particle trapped in a finite potential well — that is, a particle confined to be in a box, but (because of the weirdness of quantum mechanics) with some probability of being found outside. That probability depends upon the energy of the particle, and because of the details of the way I defined that energy (starting at a negative number, instead of the more natural value of zero), I got confused about the signs of some of the quantities I was dealing with. I explained the concepts (I think) completely correctly, but with mistakes in the math behind them, the students (and me) got confused about the details. But many, many thanks to the students who kept pressing me on the issue and helped us puzzle out the problems.
Today’s mistake was less conceptual, but no less annoying — I wrote (and said) “cotangent” when I meant “tangent” (and vice versa). In my notes, this was all completely correct, but when you’re standing up in front of 200 or so students, sometimes you miss the detail on the page in front of you. Again, this was in some sense just a mathematical detail, but (as we always stress) without the right math, you can’t really understand the concepts. So, thanks to the students who saw that I was making a mistake, and my apologies to the whole class.
First, my apologies that I couldn’t resist the almost not-safe-for-work title, especially to those expecting posts about astrophysics and cosmology rather than a reference to a 1987 record by Big Black (which it’s worth pointing out can be found in its entirety on YouTube). But this is not a post about Big Black.
Rather, it’s a brief reminiscence of another album with a similar subject matter and a very different style, Liz Phair’s Exile in Guyville, which I was shocked to discover is about to have its 20th anniversary, also commemorated with an article and interview in the Chicago Tribune.
I lived in Chicago in the early 90s when Exile In Guyville was released, although I don’t think I heard it until I left town and moved to Toronto a few months later. But she was already a presence on the scene when Chicago was taking its place in the world of post-Nirvana indie-rock (led by the Smashing Pumpkins, along with Urge Overkill, who never quite capitalised on the marquee placement of their “Girl, You’ll Be A Woman Soon” cover on the Pulp Fiction soundtrack, and my favourite, Eleventh Dream Day). It was a record full of great songs about fucking and love and being a lonely twenty-something hipster in a big city, and was a sort of homage to the Rolling Stones’ own Exile on Main Street, all of which was enough to make rock critics (and wannabes like me) wet their pants — although by now I’m sure the Stones reference is irrelevant to record’s brilliance. “Guyville” was code (surfacing first in an Urge Overkill song) for the Wicker Park neighbourhood which was the center of the Chicago rock scene, and home to my second-favourite Chicago bar, the still-going-strong Rainbo Club (alas, my favourite, Ciral’s House of Tiki, closed in 2000).
And the title of this post also covers The Book of Mormon, which I went to see in London’s West End last week, the filthy and wonderful musical comedy from the creators of South Park. Despite songs about sex with amphibians (and worse), a character named “General Butt Fucking Naked” (sort of named after a real Liberian warlord), and being self-consciously suffused with coarse stereotyping of Africans and the eponymous Mormons, manages to be old-fashioned, warm-hearted and strangely, uncynically, affirming of the ability of individuals to actually make a difference in each other’s lives.
Today was the deadline for submitting so-called “White Papers” proposing the next generation of the European Space Agency satellite missions. Because of the long lead times for these sorts of complicated technical achievements, this call is for launches in the faraway years of 2028 or 2034. (These dates would be harder to wrap my head around if I weren’t writing this on the same weekend that I’m attending the 25th reunion of my university graduation, an event about which it’s difficult to avoid the clichéd thought that May, 1988 feels like the day before yesterday.)
At least two of the ideas are particularly close to my scientific heart.
The Polarized Radiation Imaging and Spectroscopy Mission (PRISM) is a cosmic microwave background (CMB) telescope, following on from Planck and the current generation of sub-orbital telescopes like EBEX and PolarBear: whereas Planck has 72 detectors observing the sky over nine frequencies on the sky, PRISM would have more than 7000 detectors working in a similar way to Planck over 32 frequencies, along with another set observing 300 narrow frequency bands, and another instrument dedicated to measuring the spectrum of the CMB in even more detail. Combined, these instruments allow a wide variety of cosmological and astrophysical goals, concentrating on more direct observations of early Universe physics than possible with current instruments, in particular the possible background of gravitational waves from inflation, and the small correlations induced by the physics of inflation and other physical processes in the history of the Universe.
The eLISA mission is the latest attempt to build a gravitational radiation observatory in space, observing astrophysical sources rather than the primordial background affecting the CMB, using giant lasers to measure the distance between three separate free-floating satellites a million kilometres apart from one another. As a gravitational wave passes through the triangle, it bends space and effectively changes the distance between them. The trio would thereby be sensitive to the gravitational waves produced by small, dense objects orbiting one another, objects like white dwarfs, neutron stars and, most excitingly, black holes. This would give us a probe of physics in locations we can’t see with ordinary light, and in regimes that we can’t reproduce on earth or anywhere nearby.
In the selection process, ESA is supposed to take into account the interests of the community. Hence both of these missions are soliciting support, of active and interested scientists and also the more general public: check out the sites for PRISM and eLISA. It’s a tough call. Both cases would be more convincing with a detection of gravitational radiation in their respective regimes, but the process requires putting down a marker early on. In the long term, a CMB mission like PRISM seems inevitable — there are unlikely to be any technical showstoppers — it’s just a big telescope in a slightly unusual range of frequencies. eLISA is more technically challenging: the LISA Pathfinder effort has shown just how hard it is to keep and monitor a free-floating mass in space, and the lack of a detection so far from the ground-based LIGO observatory, although completely consistent with expectations, has kept the community’s enthusiasm lower. (This will likely change with Advanced LIGO, expected to see many hundreds of sources as soon as it comes online in 2015 or thereabouts.)
Full disclosure: although I’ve signed up to support both, I’m directly involved in the PRISM white paper.
Another technical note: I’ve just reformatted the whole blog. Let me know if there are any problems (or if you just think it’s ugly).
Just a quick note that the blog has been having some issues with its infrastructure: pointers to individual entries seem to be broken.
I’m on the case — apologies if you can’t get to anything you’re looking for.
Update: fixed, I think. Let me know if there are any further problems. (The blog should be a bit faster, too, as I’ve moved over to statically publishing all the pages. Don’t worry if you don’t know what that means.)