In the Dark

The super-compressible Cosmic Microwave Background

I just came across this blog post, one of a series on cosmology from the African Institute for Mathematical Sciences, which is in Muizenberg near Cape Town, South Africa. I thought I’d reblog it, partly because it’s on a topic I often discuss in talks and partly because I wanted to draw your attention the site and the other interesting posts on it.

In this article Bruce Bassett explains just how much of the information we get from measurements of the Cosmic Microwave Background can be squeezed into precise estimates of just a few parameters. The only point I would add is that this does assume at the outset that all relevant information is contained within the angular power spectrum; that’s not necessarily the case, but we don’t have any compelling evidence that it’s a wrong assumption for the CMB; see here for a previous discussion of this.

Cosmology at AIMS

One of the most striking features about the Cosmic Microwave Background (CMB) is that it is incredibly compressible from an information content point of view. The Planck satellite produced maps with of order a billion pixels whose information could be compressed almost perfectly into a power spectrum of order one thousand real numbers.

This already is a massive compression. But in addition, most of this information can be compressed further into just six of the parameters of the standard model, yielding a total compression of about one billion to one. This is both remarkable and annoying because we want to be surprised and find things that we can’t explain. And if there are things we can’t explain we want to have clear signals data about them, not just vague hints of their existence.

Anyway, to illustrate just how efficient the compression is, I took the binned WMAP 9 TT power spectrum…

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Irony 101

Posted in Uncategorized with tags Birmingham University, Vandalism on February 3, 2014 by telescoper

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Scott Tremaine on “Astrohype”

Posted in Astrohype, The Universe and Stuff with tags Scott Tremaine on February 2, 2014 by telescoper

I recently came across a post by distinguished astrophysicist Scott Tremaine who works at the Institute for Advanced Study in Princeton. The piece is entitled “Overblown Statements in Press Releases Undermine Science”, something that exercised me so much that I invented the category Astrohype so I could post particularly egregious examples on this blog.

Soctt Tremaine’s piece is on the American Astronomical Society website, but I’m reposting the text here to give it wider circulation as I think it makes some very important points that we’d all do well to heed. And of course in the interest of full disclosure I should point out that I am a theoretical astrophysicist myself, so may be a bit biased…

–o–

In a recent column, AAS President David Helfand argued correctly that negative public messages about subfields within our own discipline, or even about other disciplines — “shooting inward at each other” — damage all of us.

Consider, then, the following public messages:

from a major research university, a press release titled “Astronomers Discover Planet that Shouldn’t Be There,”
from the European Southern Observatory, a press release titled “Turning Planetary Theory Upside Down,”
from the National Radio Astronomy Observatory, a press release containing the quote, “Much of what we thought we understood about the physics of pulsars and neutron stars may be wrong,”
from the Space Telescope Science Institute, a press release stating, “New observations from NASA’s Hubble Space Telescope challenge 30 years of scientific theory about quasars,” and
from a respected news organization, an interview with a prominent exoplanet researcher containing the quote, “Theory has struck out.”

The point is not whether these messages provide accurate characterizations of the state of theoretical understanding in their respective subject areas (though in most cases they do not). The point is that by belittling and trivializing the efforts of theoretical astrophysicists — who try to understand extremely complex processes in exotic environments, with limited clues from observations — they damage the public perception of the entire astronomy community. As just one example, statements from press releases such as those above are often repeated on creationist websites, where they carry extra weight because they have the imprimatur of NASA or a major observatory or university.

Advances in observational astronomy are spectacular enough to appeal to the public on their own merits, without “shooting inward” at efforts to understand these observations. Astronomers and press officers can provide a more realistic picture of the synergy between observation and theory, and in so doing would improve the public perception of astronomy research in particular and of the scientific enterprise more generally.

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Mirror in February

Posted in Poetry with tags Mirror in February, Poem, Poetry, Thomas Kinsella on February 2, 2014 by telescoper

The day dawns with scent of must and rain,
Of opened soil, dark trees, dry bedroom air.
Under the fading lamp, half dressed – my brain
Idling on some compulsive fantasy-
I towel my shaven jaw and stop, and stare,
Riveted by a dark exhausted eye,
A dry downturning mouth.

It seems again that it is time to learn,
In this untiring, crumbling place of growth
To which, for the time being, I return.
Now plainly in the mirror of my soul
I read that I have looked my last on youth
And little more; for they are not made whole
That reach the age of Christ.

Below my window the awakening trees,
Hacked clean for better bearing, stand defaced
Suffering their brute necessities,
And how should the flesh not quail that span for span
Is mutilated more? In slow distaste
I fold my towel with what grace I can,
Not young and not renewable, but man.

by Thomas Kinsella (b. 1928)

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A Partly Political Message

Posted in Politics on February 1, 2014 by telescoper

You may decide for yourself who this is aimed at!

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One Year in Sussex

Posted in Biographical, Brighton with tags School of Mathematical and Physical Sciences, University of Sussex on February 1, 2014 by telescoper

Well, it’s the First of February which means it’s a year to the day since I started my current job as Head of the School of Mathematical Sciences at the University of Sussex, or MPS for short.

It’s been an eventful year, and not really like I expected. What I mean is that I knew it would be hard work, but the hardest bits were not the things I’d imagined. The first half of the year was primarily involved with appointing new staff to the School. All the interviews and other activities associated with that took up a huge amount of time but I think it all went well in the end. The number of full-time staff in MPS has increased by more than 50% over this time; from 15 to 23 in Mathematics (including 3 new Professors) and from 23 to 38 in Physics & Astronomy. The primary motivation for this is growth in student numbers: the number of undergraduates in Physics & Astronomy has doubled in the last three years or so, and this year we had our biggest ever intake of over 140 students.

All that wasn’t my doing, of course. The expansion of staff numbers was planned before I arrived, and the increase in student numbers is down to hard work by the admissions team.

I spent the latter part of last year involved with planning further expansion of our research activity as the contribution of MPS to the University’s Strategic Plan and am looking forward to turning that into reality over the next year or so.

I’ve tried to ensure that MPS is a friendly and open place for all staff and students, where everyone has a say and everyone feels valued. It’s not for me to say how well I’ve succeeded in that, but I’ll carry on trying.

I should mention some of the frustrations. One is that I became an academic in the first place because I enjoy both teaching and research. When I became Head of School here I found I had so many administrative duties that I had very little time for either of those activities. I got especially depressed about not being involved in teaching because I didn’t see how I could properly understand how things work in MPS without working at the coalface.

Against the advice of several colleagues I decided to teach a full module this year on Theoretical Physics to a class of about 50 students. It’s been a struggle to find the time to prepare everything, as I’m doing this for the first time, but I’ll persevere. Hopefully the students will bear with me while I get my act together. I’m very impressed with their engagement with the material so far, but then they have chosen the Theoretical Physics option so are obviously the intellectual elite of MPS; obviously, that’s my theorist’s bias speaking!

Oh, and in my spare time I grew a beard:

I suppose that will have to do. I’ll be heading up to campus shortly to spend Saturday afternoon in the office. A Head of School’s work is never done..

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A Sussex story!

Posted in Uncategorized on January 31, 2014 by telescoper

A very touching blog post from a Sussex student who graduated In Absentia this week…

ahostofpeople

29 January 2014

The stage is set, the lights are on…the Brighton dome is electric with energy and booming with excitement. Miles away, I am sitting across the computer with sparkling eyes and a beating heart. Awaiting the live streaming to begin…awaiting my graduation ceremony to commence.

Today, 2 months into the professional world, I turn around for a peek into the student life once again. As my classmates walk across the stage, I share in their happiness, I share in their smiles and just a tiny shiver of disappointment travels through me. I envision them laughing their hearts out, breathing a sigh of relief for finally and officially crossing the bridge from being graduands to becoming graduates. ‘In absentia’ the University confers the degree upon me as well, and an audible sigh of relief escapes my lips. “Yes, I have done it!”

From being a Sussex post-graduate student, I…

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Breakfast with BIMM and Cake with MPS

Posted in Biographical, Education, Music with tags Brighton Institute of Modern Music, University of Sussex on January 31, 2014 by telescoper

Another very busy day means I’ve almost reached the end of a very busy week. I spent this morning in a meeting with colleagues from the University of Sussex and representatives of the Brighton Institute for Modern Music (also known as BIMM), which focusses on courses intended to prepare students to work in some aspect of the popular music industry, including performing and songwriting as well as, e.g., management.

It’s one of the odd things about being a Head of School that you get invited to do strange things every now and again and this was one such occasion. The University of Sussex validates degree programmes for a number of education institutions, BIMM being one of them and it was my job to Chair a session this morning (at a location in central Brighton) that formed part of the validation process. We had some nice pastries for breakfast too.

Regular readers of this blog (both of them) will know that I’m not really up to date on popular beat combos so I wasn’t picked for this task for any music expertise; the idea was rather that being a complete ignoramus I could be an impartial Chair…

It was great to talk to have the chance to talk to some of the current BIMM students as well as the staff and one of the things that struck me was that although I work in a very different discipline, many of the educational challenges faced by the School of Mathematical and Physical Sciences and BIMM are very similar. I can’t talk about the details we discussed, but it was a very friendly meeting and there was lots of constructive discussion.

That business concluded it was back up to Falmer for a quick lunch and a meeting about undergraduate admissions. And finally, because it’s the last Friday of the month it was time this afternoon for our monthly MPS cake event. This month’s cake had a vaguely mathematical theme and also raised the issue of the correct plural of the word conundrum:

I thought it was appropriate to invite the Head of the Department of Mathematics, Miro Chlebik, to solve this particular conundrum by cutting the cake:

The cake vanished pretty quickly thereafter.

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Jazz Musicians Play Classical…

Posted in Jazz, Music with tags Benny Goodman, Keith Jarrett, Mozart Clarinet Quintent, Wynton Marsalis on January 30, 2014 by telescoper

I had an interesting exchange via Twitter the other day after listening to “CD Review” on BBC Radio 3. The programme included a few examples of Opera singers trying – and, in my opinion, failing – to sing like Jazz singers.

I was reminded of this discussion last night when I got home to find a lovely Clarinet sonata by Poulenc being played. It turns out that this piece was commissioned by none other than the “King of Swing”, clarinetist Benny Goodman.

I love both Jazz and Opera, but attempts to mix the two very different genres are not often successful. Jazz and Classical music are rather like different languages and musicians are rather like poets: fully bilingual exponents who can perform their art in more than one tongue are few and far between. There are, however, notable exceptions to this rule if not among singers but among instrumentalists. I think this is largely because so many Jazz musicians are so unbelievably virtuosic on their instruments that they can play more-or-less anything they put their mind to.

Anyway, I thought I’d post a few examples of famous Jazz musicians who have proved that they can play Classical music well. Here’s the man Benny Goodman playing the Mozart Clarinet Quintet K. 581:

Wynton Marsalis playing a Haydn Trumpet Concerto:

Keith Jarrett playing the first movement of the Italian Concerto by J.S. Bach BWV971. I would have included his version of the Goldberg Variations, but it’s on harpsichord and therefore not allowed…

I’d like to hear any further suggestions of excellent performances of Classical repertoire by Jazz musicians, so feel free to comment through the box.

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Methods of Images

Posted in Biographical, Cute Problems, Education with tags electrostatics, method of images, Physics, Sanjeev Baskar, University of Sussex Winter graduation on January 29, 2014 by telescoper

I’ve had a very busy day today including giving a lecture on Electrostatics and the Method of Images and, in an unrelated lunch-hour activity, filing my tax return (and paying the requisite bill). The latter was the most emotionally draining.

With no time for a proper post, I thought I’d give some examples of the images produced by yesterday’s graduands, including some who used a particular approach called the Method of Selfies. Unfortunately some of these are spoiled by having a strange bearded person in the background.

But first you might like to try the following example using the actual Method of Images:

Given two parallel, grounded, infinite conducting planes a distance a apart, we place a charge +q between the plates, a distance x from one of them. What is the force on the charge?

This is, in fact, from Griffiths, David J. (2007) Introduction to Electrodynamics, 3rd Edition; Prentice Hall – Problem 3.35.

Solutions via the comments box as usual, please.

And now here are some of the official pictures from yesterday