Archive for August, 2014

COSMIC BLACKBODY ALIVE AND WELL IN MAINSTREAM PHYSICS ESTABLISHMENT

Posted in Uncategorized on August 22, 2014 by telescoper

As an “intellectual poseur” I couldn’t resist reblogging this piece …

dreamheron's avatarThe Dreamheron Chronicles

Just this summer, Professor Amber Miller of Columbia University (appearing at the World Science Festival panel discussion on BICEP2), stated emphatically (and it seems, not required by the context of the discussion) that the cosmic blackbody is intact. Her taxpayer-funded high-tech research in the high frontier is riding on this assumption. (Watch the video from 1:07 to 1:09).

A video released last month by the learned society SPIE and filmed at NASA Goddard pointedly avers that the blackbody is fully intact, with 50 ppm accuracy.

And today this bit of public education from Professor Peter Coles of the University of Sussex (upon holding many consultations with mainstream colleagues at a conference on this very subject in Denmark) states:

The problem – the Achilles Heel of BICEP, so to speak – is that it operates at a single frequency, 150 GHz. That means that it is not possible for this experiment…

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BICEP2: Watch this Space!

Posted in The Universe and Stuff with tags , , , on August 21, 2014 by telescoper

One of the advantages of informal workshops like this one I’m attending in Copenhagen right now is that there’s a lot of time for discussions and picking up various bits of gossip. Some of the intelligence gathered in this way is unreliable but often it represents knowledge that’s widely known in the cosmological community but which I’ve missed because I don’t spend as much time on the conference circuit these days.

Anyway, those of you with more than a passing interest in cosmology will remember the results from the BICEP2 experiment announced with a great fanfare of publicity in March this year. A significant number of eminent cosmologists immediately seized on the detection of B-mode correlations in the polarized cosmic microwave background as definitive proof of the existence of primordial gravitational waves. Some went even further, in fact, and claimed that the BICEP2 results prove all kinds of other things too.

As time passed, however, and folks had time to digest some of the details presented by the BICEP2 team, there has been a growing unease about the possibility that the measurements may have been misinterpreted. The problem – the Achilles Heel of BICEP, so to speak – is that it operates at a single frequency, 150 GHz. That means that it is not possible for this experiment on its own to determine the spectrum of the detected signal. This is important because it is not only the cosmic microwave background that is capable of producing polarized radiation at a frequency of 150 GHz, foreground dust inside our own Galaxy being the prime suspect as an alternative source. It should be possible to distinguish between dust and CMB using measurements at different frequencies because the microwave background has a black-body spectrum  whereas dust does not. However, BICEP2 maps only a small part of the sky and at the time of the announcement there were no other measurements covering the same region, so a convincing test has not so far been possible.

 

cmbspectrum

The measured spectrum of the cosmic microwave background. It’s indistinguishable from the theoretical black-body curve shown as a solid line

The initial BICEP2 announcement included a discussion of foregrounds that concluded that these were expected to be much lower than their detected signal in the area mapped, but serious doubts have emerged about the accuracy of this claim. Have a look at my BICEP2 folder to see more discussion.

More recently, in July, it was announced that the BICEP2 team would collaborate with the large consortium working on the analysis of data from the Planck experiment to try to resolve these difficulties. Planck not only covers the whole sky but also has detectors making measurements over a wide range of frequencies (all the way up to 857 GHz). This should provide a definitive measurement of the contribution of Galactic dust to the BICEP2 field and at last give us a strong experimental basis on which to decided whether the BICEP2 signal is primordial or not. The result of my informal poll on BICEP2 was a clear majority (~62%) in favour of the statement that it was “too early to say” what the BICEP2 signal actually represents.

Anyway, I have it on very good authority that Planck’s analysis of the Galactic foregrounds in the BICEP2 region will be published (on the arXiv) on or around September 1st 2014. That’s just about 10 days from now. Maybe then this tantalizing wait will be over. I’ll try my best to post about the results when it comes out. In the meantime, I thought I’d do something completely unscientific and try to gauge what how current opinion stands on this issue by means of a poll of the total unrepresentative readership of this blog. Suppose you had to bet on whether the BICEP2 result is due to (a) primordial gravitational waves or (b) Galactic foregrounds, which would you go for?

Of course, those working on this project probably know the answer already so they’ll have to decide for themselves whether they wish to vote!

Riverbed

Posted in Art with tags , , , , on August 20, 2014 by telescoper

Yesterday afternoon I skived off the last session of the workshop I’m attending and took the train to the small town of Humlebæk, which is about 35 north of Copenhagen and is the site of the Louisiana Museum of Modern Art. The purpose of my visit was to attend an invitation-only preview of a new installation by Olafur Eliasson called Riverbed. The invitation to this came relatively recently and it was only the coincidence of my being here at this workshop that made it possible for me to attend.

As it turned out, I arrived quite early and the weather was fine, so I took the chance to wander around the sculpture park before the main event. There are many fine works there. This, for example, is by Henry Moore:

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This one is by Henri Laurens

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And so to Riverbed. This is a large work featuring boulders and gravel, brought all the way from Iceland, which have been used to recreate a section of the landscape of Olafur’s native land. The distinctive colouring and granularity of the raw material produces terrain of a texture that must look very alien to anyone who has never been to Iceland. The installation is contained within a space which is contained within and divided by stark white-painted walls, with rectangular gaps where necessary to let the water through from room to room. These boundaries, with their geometrically precise edges, affect the experience of the naturalistic landscape in a very interesting way. The Riverbed itself may look “natural” but the structures surrounding it constantly remind you that it isn’t. Viewers are permitted to wander through the piece wherever they like and interact however they please, sitting down on a boulder, paddling in the stream or even just watching the other people (which is mainly what I did). I don’t know what’s more interesting, the work itself or the way people behave when inside it!

Here are some pictures I took, just to give you a flavour:

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Anyway, after that we adjourned for a drinks reception and a splendid dinner in the Boat House, which part of the Louisiana complex. Being neither an artist nor an art critic I felt a bit of an outsider, but I did get the chance to chat to quite a few interesting people including, by sheer coincidence, a recent graduate of the University of Sussex. The Boat House looks out towards the island of Hven, home of the observatory of Tycho Brahe, so naturally I took the opportunity to drink a toast to his memory:

Bvat-UeCAAA9u4p

After that I had to return to Copenhagen to write my talk, as I was on first this morning at 9.30. This afternoon we have a bit of a break before the conference excursion and dinner this evening. The excursion happens to be to Louisiana Museum of Modern Art (although we’re all going by bus this time); dinner is in the cafeteria rather than the Boat House, though..

On Problems

Posted in Poetry, The Universe and Stuff with tags , , , on August 19, 2014 by telescoper

Since I’m in Denmark I thought I’d put up one of the wonderfully witty little poems written by Danish mathematician Piet Hein. He called each of these verses a “grook” (or actually, in Danish, the word is gruk) and he wrote thousands of them over his long life. I’ve posted one of these before but this one is even shorter but it makes a deep point, the danger of becoming be trapped by your own assumptions. I won’t comment on the relevance of this to the cosmology workshop I’m attending…

Our choicest plans
have fallen through
our airiest castles
tumbled over
because of lines
we neatly drew
and later neatly
stumbled over.

by Piet Hein (1905-1996).

Copenhagen, Cosmology and Coleman Hawkins

Posted in Biographical, Jazz, The Universe and Stuff with tags , , on August 18, 2014 by telescoper

Now that I’ve finally checked into my hotel in the wonderful city of Copenhagen I thought I’d briefly check in on the old blog as well. I’m here once again for a meeting, this time as an invited speaker at the 2nd NBIA-APCTP Workshop on Cosmology and Astroparticle Physics; NBIA being the Niels Bohr International Academy (based in Denmark) and APTCTP being the Asia Pacific Centre for Theoretical Physics (based in Korea). This is the kind of meeting I actually like, with relatively few participants and lots of time for discussion; as a welcome gesture for the first day there was also free beer!

I decided for some reason to try an experimental route getting here. There wasn’t a flight at a convenient date and  time from Gatwick, the nearest airport to my Brighton residence, so I decided to get an early morning flight from Heathrow instead. The departure time of 06:40, however, left me with the difficulty of getting there in time by public transport as the relevant trains don’t run overnight. I toyed with the idea of booking an airport hotel for the night, but decided that would be extravagant so instead opted to get a coach from Brighton; this was cheap and comfortable – only a handful of other passengers got on the bus – and got me there right on schedule. The downside was that I had to catch the 01:40 from Brighton Coach Station, which arrived at about 4am at Heathrow Terminal 3. It was quite interesting finding the normally busy terminal almost deserted but although I did a self-service check-in straight away the bag drops didn’t open until almost 5am. None of the cafes in the check-in area were open, so I had to hang around for an hour before finally getting rid of my luggage and passing through to the airside whereupon I nabbed some coffee and a bite to eat.

The flight was almost uneventful. Unfortunately, however, as we came in to land at Copenhagen’s Kastrup airport, a young person sitting behind me vomited uncontrollably and at considerable length, producing a steady flow both of chunder and unpleasant noises. The aftermath was quite unpleasant, so I was quick out of the blocks when the plane finally came to a stop at the gate. An aisle seat turned out to have been a wise choice.

Assuming it would be too early to check into the hotel that had been booked for me, I decided to go straight to the meeting but got to the Niels Bohr Institute’s famous Auditorium A near the end of the first talk, about the Imprint of Radio Loops on the CMB (a subject I’ve blogged about), which is a shame because (a) its interesting and (b) some of my own work was apparently discussed. That happens so rarely these days I’m sorry I missed it.

I was a bit tetchy as a result of my sleepless night, though I limited the expression of this to a  couple of rants about frequentist statistics during the discussions.

After the free beer I finally made my way to the hotel and checked in. It’s not bad, actually. There can’t be that many hotel rooms that have a picture of the great tenor saxophonist Coleman Hawkins on the wall:

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Anyway, I was due to give the conference summary on Friday but I’ve been moved forward to Wednesday so I’d better think of something to say. Maybe in the morning though, I could do with an early night…

Newcastle Joins the Resurgence of UK Physics

Posted in Education, Science Politics, The Universe and Stuff with tags , , , on August 17, 2014 by telescoper

I’ve posted a couple of times about how Physics seems to undergoing a considerable resurgence in popularity at undergraduate level across the United Kingdom, with e.g. Lincoln University setting up a new programme. Now there’s further evidence in that Newcastle University has now decided to re-open its Physics course for 2015 entry.

The University of Newcastle had an undergraduate course in Physics until 2004 when it decided to close it down, apparently owing to lack of demand. They did carry on doing some physics research (in nanoscience, biophysics, optics and astronomy) but not within a standalone physics department. The mid-2000s were tough for UK physics,  and many departments were on the brink at that time. Reading, for example, closed its Physics department in 2006; there is talk that they might be starting again too.

The background to the Newcastle decision is that admissions to physics departments across the country are growing at a healthy rate, a fact that could not have been imagined just ten years ago. Times were tough here at Sussex until relatively recently, but now we’re expanding on the back of increased student numbers and research successes. Indeed having just been through a very busy clearing and confirmation period at Sussex University, it is notable that its the science Schools that have generally done best.  Sussex has traditionally been viewed as basically a Liberal Arts College with some science departments; over 70% of the students here at present are not studying science subjects. With Mathematics this year overtaking English as the most popular A-level choice, this may well change the complexion of Sussex University relatively rapidly.

I’ve always felt that it’s a scandal that there are only around 40 UK “universities” with physics departments Call me old-fashioned, but I think a university without a physics department is not a university at all; it’s particularly strange that a Russell Group university such as Newcastle should not offer a physics degree. I believe in the value of physics for its own sake as well as for the numerous wider benefits it offers society in terms of new technologies and skills. Although the opening of a new physics department will create more competition for the rest of us, I think it’s a very good thing for the subject and for the Higher Education sector general.

That said, it won’t be an easy task to restart an undergraduate physics programme in Newcastle, especially if it is intended to have as large an intake as most successful existing departments (i.e. well over 100 each year). Students will be applying in late 2014 or early 2015 for entry in September 2015. The problem is that the new course won’t figure in any of the league tables on which most potential students based their choice of university. They won’t have an NSS score either. Also their courses  will probably need some time before it can be accredited by the Institute of Physics (as most UK physics courses are).

There’s a lot of ground to make up, and my guess is that it will take some years to built up a significant intake.The University bosses will therefore have to be patient and be prepared to invest heavily in this initiative until it can break even. The decision a decade ago to cut physics doesn’t exactly inspire confidence that they will be prepared to do this, but times have changed and so have the people at the helm so maybe that’s an unfair comment.

There are also difficulties on the research side (which is also vital for a proper undergraduate teaching programme), there are also difficulties. Grant funding is already spread very thin, and there is little sign of any improvement for the foreseeable future  in the “flat cash” situation we’re currently in. There’s also the stifling effect of theResearch Excellence Framework I’ve blogged about before. I don’t know whether Newcastle University intends to expand its staff numbers in Physics or just to rearrange existing staff into a new department, but if they do the former they will have to succeed against well-established competitors in an increasingly tight funding regime. A great deal of thought will have to go into deciding which areas of research to develop, especially as their main regional competitor, Durham University, is very strong in physics.

On the other hand, there are some positives, not least of which is that Newcastle is and has always been a very popular city for students (being of course the finest city in the whole world). These days funding follows students, so that could be a very powerful card if played wisely.

Anyway, these are all problems for other people to deal with. What I really wanted to do was to wish this new venture well and to congratulate Newcastle on rejoining the ranks of proper universities (i.e. ones with physics departments). Any others thinking of joining the club?

Sussex and the World Premier League of Physics

Posted in Education, The Universe and Stuff with tags , , , , , on August 16, 2014 by telescoper

In the office again busy finishing off a few things before flying off for another conference (of which more anon).

Anyway, I thought I’d take a short break for a cup of tea and a go on the blog.

Today is the first day of the new Premiership season and , coincidentally, last week saw some good news about the Department of Physics and Astronomy at the University of Sussex in a different kind of league table.

The latest (2014) Academic Rankings of World Universities (often called the “Shanghai Rankings”) are out so, as I suspect many of my colleagues also did, I drilled down to look at the rankings of Physics departments.

Not surprisingly the top six (Berkeley, Princeton, MIT, Harvard, Caltech, & Stanford) are all based in the USA. The top British university is, also not surprisingly, Cambridge in 9th place. That’s the only UK university in the top ten for Physics. The other leading UK physics departments are: Manchester (13th), Imperial (15th), Edinburgh (20th), Durham (28th), Oxford (39th) and UCL (47th). I don’t think there will be any surprise that these all made it into the top 50 departments worldwide.

Just outside the top 50 in joint 51st place in the world is the Department of Physics & Astronomy at the University of Sussex. For a relatively small department in a relatively small university this is a truly outstanding result. It puts the Department  clear in 8th place in the UK, ahead of Birmingham, Bristol, Leicester, Queen Mary, Nottingham, Southampton,  St Andrews, Lancaster, Glasgow, Sheffield and Warwick, all of whom made the top 200 in the world.

Incidentally, two of the other departments tied in 51st place are at Nagoya University in Japan (where I visited in January) and Copenhagen University in Denmark (where I’m going next week).

Although I have deep reservations about the usefulness of league tables, I’m not at all averse to using them as an excuse for a celebration and to help raise the profile of Physics and Astronomy at Sussex generally.  I’d therefore like to take the opportunity to offer hearty congratulations to the wonderful staff of the Department of Physics & Astronomy on their achievement. 

With the recent investments we’ve had and further plans for growth I hope over the next few years we can move even further up the rankings. Unless of course the methodology changes or we’re subect to a “random” (ie downward) fluctuation…

 

 

 

Fiery Fred

Posted in Cricket with tags , , on August 15, 2014 by telescoper

Since there’s a Test Match going on right now at the Oval and I’ve got a few minutes before my next task, I thought I’d just do a brief post to mark the anniversary of a very special cricketing moment. On this day in 1964, also at the Oval, Sir Fred Trueman became the first bowler to take 300 wickets in test matches. In his test career overall he took 307 wickets at an astonishingly low average of 21.57. He twice bowled spells in Test matches in which he took five wickets without conceding a run.

Here’s a short video to remind us all of what a superb action Fiery Fred Trueman had:

p.s. Fred Trueman was born in Yorkshire which, as you all know, is part of the Midlands.

Do-It-Yourself Supernova Explosion

Posted in Education, The Universe and Stuff with tags , , , , on August 15, 2014 by telescoper

Visitors to the office of the Head of the School of Mathematical and Physical Sciences at the University of Sussex often remark upon the presence of these two objects and inquire as to their purpose:

Supernova

Since I don’t play golf and am a bit long in the tooth to be a fan of Peppa Pig, most assume that it must be for some strange astrophysical reason. I tried asking on Twitter what people think I use them for, and the most common answer was to demonstrate the relative size of the Earth and Moon. As Roy Walker would have said, “That’s a good answer, but it’s wrong”.

In fact I use the objects concerned to demonstrate what goes on when a star goes supernova.

The point is that a supernova explosion begins with gravitational collapse of the progenitor star, so why does that manifest itself as an explosion? The point is that the outer layers are blown off while the core collapses into a compact object such as a neutron star or, perhaps, a black hole.

The way to demonstrate this is first to balance the golf ball (representing the outer layers) on top of the beach ball; the air hole in the latter is a useful place to do this. You then lift the conjoined objects to a reasonable height and drop them onto the table or bench provided for such a purpose in a lecture theatre. The objects fall together under gravity until the beach ball hits the surface. You will find that the beach ball (representing the core) stops still while the golf ball (representing the outer shells) shoots upwards as most of the kinetic energy of the system is transferred to it during the bounce.

I think this is quite an effective demonstration, but I’d encourage inexperienced lecturers to note that there is a Health and Safety Issue, so it is necessary to carry out a risk assessment before attempting it. When I first did this during a lecture many years ago, I used a ball bearing rather than a golf ball and a fully-inflated and much larger beach ball instead of the more manageable (and slightly deflated) Peppa Pig one I now use. I told the students in the audience to watch carefully what happened and then dropped them as described above…

What happened in that case was that the ball bearing rocketed up so fast that it reached the ceiling and smashed into the lights above the lecturer’s bench, whereupon there was a very loud bang and I was showered with broken glass and other debris. I have to say that got the loudest round of applause I’ve ever had while lecturing, but it wasn’t exactly the effect I’d been hoping for.

But the real reason for posting today is to wish a very happy 65th birthday to supernova expert extraordinaire and occasional reader of this blog, Robert Kirshner of Harvard University, who has celebrating along with a number of my astro-chums at a conference in Australia.

Many happy returns, Bob!

An American doctor experiences an NHS emergency room

Posted in Politics on August 14, 2014 by telescoper

Interesting perspective on our wonderful National Health Service…

Dr. Jen Gunter's avatarDr. Jen Gunter

You know it’s going to be one of those days when one of the first tweets on vacation inquires about the closest hospital.

IMG_8896Victor, one of my 11-year-olds, had something in his eye courtesy of a big gust of wind outside of Westminster Abby. He was complaining enough to let me flip his eyelid and irrigate his eye on the square in front of Big Ben. (I’m sure several people thought I was torturing him).  Despite an extensive search and rinse mission no object or relief was to be found. I fretted about going to the hospital. It wasn’t the prospect of navigating a slightly foreign ER, but simply the prospect of the wait. While I am a staunch supporter of the British NHS in the back of my mind I envisioned a paralyzingly full emergency room and an agonizing 18 hour wait only to find he had nothing in his…

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