Gravitational waves detected. Einstein was right … again

Posted in The Universe and Stuff on February 11, 2016 by telescoper

Some more reaction to the LIGO result…

Adam Day's avatarCQG+

Clifford Will Clifford Will is the Editor-in-Chief of Classical and Quantum Gravity

As if celebrating the 100th birthday of general relativity weren’t enough, the LIGO-Virgo collaboration has provided “the icing on the cake” with today’s announcement of the first direct detection of gravitational waves. At press conferences in the USA and Europe, and in a paper in Physical Review Letters published afterward, the team announced the detection of a signal from a system of two merging black holes.

The signal arrived on 14 September, 2015 (its official designation is GW150914), and was detected by both the Hanford and Livingston advanced detectors of the LIGO observatory (the advanced Virgo instrument in Italy is not yet online). It was detected first by

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LIGO: Live Reaction Blog

Posted in The Universe and Stuff with tags , , , , on February 11, 2016 by telescoper

So the eagerly awaited press conference happened this afternoon. It started in unequivocal fashion.

“We detected gravitational waves. We did it!”

As rumoured, the signal corresponds to the coalescence of two black holes, of masses 29 and 36 times the mass of the Sun.

The signal arrived in September 2015, very shortly after Advanced LIGO was switched on. There’s synchronicity for you! The LIGO collaboration have done wondrous things getting their sensitivity down to such a level that they can measure such a tiny effect, but there still has to be an event producing a signal to measure. Collisions of two such massive black holes are probably extremely rare so it’s a bit of good fortune that one happened just at the right time. Actually it was during an engineering test!

Here are the key results:

 

LIGO

 

Excellent signal to noise! I’m convinced! Many congratulations to everyone involved in LIGO! This has been a heroic effort that has taken many years of hard slog. They deserve the highest praise, as do the funding agencies who have been prepared to cover the costs of this experiment over such a long time. Physics of this kind is a slow burner, but it delivers spectacularly in the end!

You can find the paper here, although the server seems to be struggling to cope! One part of the rumour was wrong, however, the result is not in Nature, but in Physical Review Letters. There will no doubt be many more!

And right on cue here is the first batch of science papers!

No prizes for guessing where the 2016 Nobel Prize for Physics is heading, but in a collaboration of over 1000 people across the world which few will receive the award?

So, as usual, I had a day filled with lectures, workshops and other meetings so I was thinking I would miss the press conference entirely, but in the end I couldn’t resist interrupting a meeting with the Head of the Department of Mathematics to watch the live stream…

P.S. A quick shout out the UK teams involved in this work, including many old friends in the Gravitational Physics Group at Cardiff University (see BBC News item here) and Jim Hough and Sheila Rowan from Glasgow. If any of them are reading this, enjoy your trip to Stockholm!

Advance Thoughts on LIGO

Posted in Uncategorized on February 11, 2016 by telescoper

By way of a warm-up to this afternoon’s announcement, here are some thoughts by another physicist…

Matt Strassler's avatarOf Particular Significance

Scarcely a hundred years after Einstein revealed the equations for his theory of gravity (“General Relativity”) on November 25th, 1915, the world today awaits an announcement from the LIGO experiment, where the G in LIGO stands for Gravity. (The full acronym stands for “Laser Interferometer Gravitational Wave Observatory.”) As you’ve surely heard, the widely reported rumors are that at some point in the last few months, LIGO, recently upgraded to its “Advanced” version, finally observed gravitational waves — ripples in the fabric of space (more accurately, of space-time). These waves, which can make the length of LIGO shorter and longer by an incredibly tiny amount, seem to have come from the violent merger of two black holes, each with a mass [rest-mass!] dozens of times larger than the Sun. Their coalescence occurred long long ago (billions of years) in a galaxy far far away (a good fraction of the distance…

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Out in STEM at the Royal Society

Posted in Biographical, LGBTQ+ with tags , , , on February 10, 2016 by telescoper

Last night I attended a very enjoyable meeting at the Royal Society in London called Out in STEM. In the 356 years that the Royal Society has been in existence this is the first event that has been devoted to a discussion of LGBT+ matters, so I feel honoured not only to have been present but to have been one of the panellists invited to start off the evening by talking about the question:

“Choosing to be out in the workplace or when studying – what influences that choice?”

In my five-minute answer to this I talked about my own personal decision to be open about my sexuality when I started as a research student at the University of Sussex way back in 1985. In fact, three of the nine panellists as well as a number of other participants did their doctorates at the University of Sussex, an institution has clearly been a kind of incubator of LGBT scientists and engineers! My decision was heavily influenced by the events of the time, chiefly the ongoing AIDS crisis and the infamous Section 28. I felt at the time that it was necessary to stand up and be counted in the face of so much prejudice, a decision which I have never regretted.

Having never really been “in” for my whole research career, coming out wasn’t really an issue for me and I have been openly at every insitution I have worked in – Sussex, Queen Mary, Nottingham and Cardiff. Although I have encounted some isolated examples of unpleasantness, I can’t say that my career has suffered any adverse consequences.

Getting back to the question, I think what influences the choice is a combination of personal factors and the environment of the institution in question. For early career researchers, the choice – and it should always be a choice – can be affected by the perception that one’s career depends on the patronage of persons higher up the hierarchy, be that PhD supervisor, research group leader or departmental head. The less hierarchical the department is, the less likely one is to feel suffocated by the need to conform. It also helps if senior managers make it clear that any bullying or harassment associated with sexual identity or other personal characteristics will not be tolerated. I have tried hard to create such an environment in the School of Mathematical and Physical Sciences, of which I am now the Head. I’ll leave it to others to judge whether or not I have succeeded.

In fact none of the nine panellists described any major adverse consequences of the decision to come out either, but stressed how positive it can be to feel liberated by being open about who you are.

After the nine short answers to the above question, we split up into small groups and discussed other questions. I enjoyed this part very much because the discussion was relaxed and wide-ranging. One theme that ran through many of the responses when groups were asked to feed back a summary of their deliberations was what a big difference it can make to have an LGBT staff network. I am proud to have played a role in the creation of such a network at the University of Sussex, although I am still saddened that it has taken so long for this institution to create one. I am also glad to say that the Institute of Physics is setting up an LGBT network of its own, with a particular emphasis on early career researchers, for whom the sense of isolation that is often involved in working on short-term contracts in highly competitive field can be exacerbated by the perceived need to conceal important aspect of their private life.

Once the discussion session was over we adjourned for wine and canapés, and informal chats. That was extremely pleasant, although I did perhaps have a bit too much wine before I dashed off to catch the train back to Brighton.

It was particularly nice to meet in person some of the people I’d previously known only through social media. I also met an old friend from my previous incarnation at Sussex, Tom Welton, who is now Dean for Natural Sciences at Imperial College. I haven’t seen Tom for over 20 years, actually. I hope we’ll be able to meet up again before too long.

Anyway, I’d like to thank the Royal Society for putting on this event, and especially to Lena Cumberbatch who did a lot of the organizing as well as trying to keep the panellists to time. I enjoyed it greatly and look forward to working with them again. I hope it’s not another 356 years until the next Out in STEM event!

 

 

 

Fat Tuesday – Eh La Bas!

Posted in Jazz with tags , , , on February 9, 2016 by telescoper

Today’s  the day we call in England  Shrove Tuesday. We’re apparently all supposed to get shriven by doing a penance before Lent . Another name for the occasion is Pancake Day, although I’m not sure what sort of pennance it is to be forced to eat pancakes.

Further afield the name for this day is a bit more glamorous. Mardi Gras, which I translated using my schoolboy French as Fat Tuesday, doesn’t make me think of pancakes but of carnivals. And being brought up in a house surrounded by Jazz, it makes me think of New Orleans and the wonderful marching bands that played not just during the Mardi Gras parades but at  just about every occasion for which they could find an excuse, including funerals.

The Mardi Gras parades gave rise to many of the great tunes of New Orleans Jazz, many of them named after the streets through which the parade would travel, mainly in  the famous French Quarter. Basin Street, South Rampart Street, and Bourbon Street are among the names redolent with history for Jazz fans and musicians around the world. I also remember a record by Humphrey Lyttelton‘s 1950s band called Fat Tuesday.

The New Orleans Mardi Gras has on recent occasions sometimes got a bit out of hand, and you probably wouldn’t want to take kids into the French Quarter for fear they would see things they shouldn’t. Personally, though, I’d love the chance to savour the atmosphere and watch the parades.  Anyway, here’s an infectious little number performed for you by the inestimable Preservation Hall Jazz Band from New Orleans; the Preservation Hall is located in the French Quarter. It’s a traditional song with original lyrics in the local Creole Patois, but often also performed in standard French. The words are all about eating, which makes it somewhat relevant to today, although that’s only their surface meaning. You might recognize the tune from other songs that borrowed the theme, but this one is the Daddy! You don’t often hear it played with as strong a Caribbean influence on the rhythm as this version, and the excellent banjo solo is evocative of the Cajun music or Louisiana, but that blending of cultures and traditions is exactly what made New Orleans such an important place in musical history…

 

The Search for Gravitational Waves

Posted in The Universe and Stuff with tags , , on February 8, 2016 by telescoper

Regardless of what will or will not be announced on Thursday, I thought it would be worth sharing this nice colloquium talk by Dr Alan Weinstein of Caltech about the search for gravitational waves, featuring the Laser Interferometric Gravitational-wave Observatory (LIGO). I’ve picked this not only because it’s a nice and comprehensive overview, but also that Professor Weinstein doesn’t call them gravity waves!

 

 

The Owl

Posted in Poetry with tags , , on February 7, 2016 by telescoper

Downhill I came, hungry, and yet not starved,
Cold, yet had heat within me that was proof
Against the north wind; tired, yet so that rest
Had seemed the sweetest thing under a roof. 

Then at the inn I had food, fire, and rest,
Knowing how hungry, cold, and tired was I.
All of the night was quite barred out except
An owl’s cry, a most melancholy cry. 

Shaken out long and clear upon the hill
No merry note, nor cause of merriment,
But one telling me plain what I escaped
And others could not, that night, as in I went. 

And salted was my food, and my repose,
Salted and sobered too, by the bird’s voice
Speaking for all who lay under the stars,
Soldiers and poor, unable to rejoice.

by Edward Thomas (1878-1917)

LIGO Newsflash

Posted in The Universe and Stuff with tags , on February 5, 2016 by telescoper

This morning I heard the same rumour from two distinct (and possibly independent) sources. That’s not enough to prove that the rumour is true, but perhaps enough to make it  repeating here.

The rumour is that, on Thursday 11th February in Washington DC at 10.40am 10.30am local time (15.40 15.30GMT), the Laser Interferometry Gravitational Wave Observatory (LIGO) will announce the direct experimental detection of gravitational waves.

If true this is immensely exciting, but I reiterate that it is, for the time being at least, only a rumour.

I will add more as soon as I get it. Please feel free to provide updates through the comments. Likewise if you have information to the contrary…

 

UPDATE: 9th February 2016. An official announcement of the forthcoming announcement has now been announced. It will take place at 10.30 local time in Washington (15.30 GMT), although it is believed the first ten minutes will involve a couple of songs by the popular vocal artist Beyoncé.

 

Measuring the lack of impact of journal papers

Posted in Open Access with tags , , , on February 4, 2016 by telescoper

I’ve been involved in a depressing discussion on the Astronomers facebook page, part of which was about the widespread use of Journal Impact factors by appointments panels, grant agencies, promotion committees, and so on. It is argued (by some) that younger researchers should be discouraged from publishing in, e.g., the Open Journal of Astrophysics, because it doesn’t have an impact factor and they would therefore be jeopardising their research career. In fact it takes two years for new journal to acquire an impact factor so if you take this advice seriously nobody should ever publish in any new journal.

For the record, I will state that no promotion committee, grant panel or appointment process I’ve ever been involved in has even mentioned impact factors. However, it appears that some do, despite the fact that they are demonstrably worse than useless at measuring the quality of publications. You can find comprehensive debunking of impact factors and exposure of their flaws all over the internet if you care to look: a good place to start is Stephen Curry’s article here.  I’d make an additional point here, which is that the impact factor uses citation information for the journal as a whole as a sort of proxy measure of the research quality of papers publish in it. But why on Earth should one do this when citation information for each paper is freely available? Why use a proxy when it’s trivial to measure the real thing?

The basic statistical flaw behind impact factors is that they are based on the arithmetic mean number of citations per paper. Since the distribution of citations in all journals is very skewed, this number is dragged upwards by a few papers with extremely large numbers of citations. In fact, most papers published have many few citations than the impact factor of a journal. It’s all very misleading, especially when used as a marketing tool by cynical academic publishers.

Thinking about this on the bus on my way into work this morning I decided to suggest a couple of bibliometric indices that should help put impact factors into context. I urge relevant people to calculate these for their favourite journals:

  • The Dead Paper Fraction (DPF). This is defined to be the fraction of papers published in the journal that receive no citations at all in the census period.  For journals with an impact factor of a few, this is probably a majority of the papers published.
  • The Unreliability of Impact Factor Factor (UIFF). This is defined to be the fraction of papers with fewer citations than the Impact Factor. For many journals this is most of their papers, and the larger this fraction is the more unreliable their Impact Factor is.

Another usefel measure for individual papers is

  • The Corrected Impact Factor. If a paper with a number N of actual citations is published in a journal with impact factor I then the corrected impact factor is C=N-I. For a deeply uninteresting paper published in a flashily hyped journal this will be large and negative, and should be viewed accordingly by relevant panels.

Other suggestions for citation metrics less stupid than the impact factor are welcome through the comments box…

 

On Religion

Posted in Uncategorized with tags , , on February 3, 2016 by telescoper

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