Thursday, 27 February 2014

Sunday, 23 February 2014

Higgs would not make it in modern academia - so what?

It's been a very busy week, hosting the ANITA 2014 Workshop and Summer School. It was an extremely good meeting, but has been quite exhausting. But today, a post about something that has been bubbling in my mind since the end of last year. Be warned, it's a bit of a ramble.

In The Guardian, physicist Jim al-Khalili reported on a chat he had with the new uber-famous Peter Higgs
In the article, Higgs reported that he "wouldn't be productive enough for today's academic system". (Actually, there's a couple or articles on this in the Guardian, the most recent, involving al-Khalili is here). Some have interpreted this as being a sign that academia is broken, and this opinion rings through the ultimate commentators on the web, those on slashdot. 

I have also heard similar comments from early- and mid-career researchers who are staring down the barrel of the leaky pipe of academic careers.

How can a Nobel prize winner be unemployable?

Before I continue, I need to lay some cards on the table. I think that the Higgs mechanism is pretty cool, and the discovery of the Higgs boson is one of the pinnacle discoveries in modern science. I'm not jumping on the band-wagon here, as I contemplated becoming a particle physicist when I, to quote Billy Joel, "wore a younger man's clothes". In fact, I was a CERN summer-student searching for, and failing to find, charged Higgs particle at L3 at the Large Electron-Positron Collider, the forerunner of Large Hadron Collider (LHC). 

I should also make it clear that I don't think that academia is perfect. In recent years, there has been a growing emphasis on impact - basically, what does the public get for the dollars it invests in research. Many countries now run immense programs to measure impact - Britain has the Research Assessment Exercise where as Australia has the Excellence in Research for Australia

These exercises look at the quality of research, much of it assessed by where a paper is published (papers in Nature and Science are seen to be "better" places for high quality research publications as opposed to the Bulgarian Journal of Basket Weaving). Also, the number of citations a paper receives (basically, how many times it is mentioned in someone else's work - note mentioned - not used) is also weighed up. 

Then there is the broader concept of impact, which can be harder to define. If there is a spin-off industry from research, that's impact. But there is also societal impact - if a result generates a media buzz and the tax-paying public finds it interesting, then that's impact.

This has led to a lot of bean-counting and navel gazing (and I should note that I am involved in this at my own university), especially as future funding may be tied to how well you do in such exercises. There is often a lot of chest-beating when the results are announced.

But some think that the exercises are flawed. Some research areas, such as maths, are notoriously slow moving, with small number of citations and taking years and decades before they are realised as being a breakthrough. And sometimes, there is a lot of focus on industrial engagement as impact is a major problem for fields such as fundamental physics.


So, getting back to the topic of the title. What Higgs is pointing out is that, given his publication record of only a handful of papers, universities would judge him to be unproductive (although his 1964 paper has an impressive number of citations). Does this mean that academia is broken?

The first thing to realise is that science has evolved a lot since Higgs was working in the 1960s. The number of people going to university has exploded, with increasing opportunities for people to go into postgraduate training. The number of people with PhDs keeps increasing, faster than the rate of faculty jobs. As many and early- and mid-career researcher knows, the number of opportunities available as you climb the tree gets less and less, and many people leave academia.

But there is another consequence of this, something which people don't like to talk about, is that academia has become more competitive, and in a competitive environment, competitive people tend to win. What do I mean?

Universities generally want to hire successful people, and success is judged on past performance, such as papers published, citations received, and grants awarded (very similar to the kind of things the Research Exercises look at!). Don't get me wrong, the potential for making future ground-breaking discoveries is very important, but while "Past Performance is No Guarantee of Future Results", a researcher's past outputs are taken as an important guide to future success. It is within this competitive environment that Higgs tells us that his CV would not stack up.
  
This is will not be news to academics reading this, but there is an important message, especially for those considering academia as a career, namely that academic careers don't just happen. Those that do well manage their careers. In this, I don't mean overhyping what's on your CV (although that does happen!), but thinking hard about the area you working in, the people you work with, where you publish your papers, which conference they talk at etc.

This sometimes comes as a shock to some. I still meet people who think that if they just hide away in their office and plug away at their problem, somehow a faculty job will find them. Ain't going to happen. 

What also comes as a shock is that academia is not a even playing field. It never is when competitive people are thrown into the mix. In all walks of life there are people willing to put in extra-hours and effort to get ahead, and academia is no different. I know that this is not music to the ears early- and mid-career researchers, as that many discussions about career progression centres on "work-life balance", but competitive people are not going to be barred from academia any time soon.

So, no, given the competitive nature of modern science, Higgs would struggle to get a job (although, once Edinburgh cottoned on that he might get a Nobel, they kept him on).

OK - I've typed a lot, but there is one more point I want to make.
What if Peter Higgs had left academia before his famous 1964 work? "Alternative history" is an interesting realm of speculation, but without Peter Higgs in academia where would be in terms of science?

Science is replete with the myth of the lone genius, the individual plugging away and coming up with the singular discovery that changes the world. This is propagated with things like the Nobel Prize which are awarded to at most three (living) researchers for a particular discovery. The lone genius is an extremely rare thing.

But, as ever, the discovery of the Higgs mechanism was more complicated than Higgs working alone, and several people were working along parallel lines. In fact, some dispute the name of the particle, based upon who they think deserve the credit for the discovery. Peter Higgs himself states that fellow physicist, Tom Kibble, should have shared the prize with him and Englert.

This often happens in science, where research is undertaken at the cutting-edge, there is a flurry of activity between differing researchers. A look at Nobel Prizes reveals that often they are given to those who were effectively in competition rather than working together.

Now, I am not trying to down-play Higgs insight and contributions, and I think he absolutely deserves the prizes given to him, but if we plucked him out of history, how different would modern science be? It's hard to tell, but I like this quote from Newton (who was often a lone genius!)
"I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me."
Science is a sea-shore of pebbles, ready to be discovered. If you don't pick one up, someone following behind you probably will (I've lost the original quote! - if you know it, answers in the box below).

To bring this post to a close, as I need to go and mow the lawn, my final thoughts.  Higgs not surviving in modern academia is not a sign that academia is broken, just that it is different to the 1960s. It is not perfect (and, to be honest, I don't even know what a perfect academia is), and has a number of problems, but we are still in an era of wonderful discoveries. It will probably be different again in 50 years time.

If Higgs had left academia, we would have lost his insight, but science would have still progressed. But here's a final thought for you to chew on. The next Einstein or Maxwell could be sitting in the slums of Mumbai, or a refugee camp in Somali, without access to education, let alone an opportunity to enter academia. When they get a proper chance to contribute to scientific advance, I am sure it will amazing, and I hope I am around to see it.

Friday, 14 February 2014

The oldest star in the universe? Maybe, maybe not!

Lightening post, as I've got to get on with cooking some Tandoori Chicken!

I've written my thoughts on the recent reports that the oldest star in the Universe has been found in an article in The Conversation. It's a great discovery, but I take a swipe at scientific reporting. More soon.

ps - I'm now followable on twitter at @Cosmic_Horizons

Monday, 10 February 2014

Hydrodynamical simulations of coupled and uncoupled quintessence models II: Galaxy clusters

Time for a quick post, and a follow-up paper to this one which I posted recently. 

As I mentioned, one of the key things people are looking at at the moment is whether the dark sector, which includes dark matter and dark energy, can evolve, change and interact over time. We're keen to understand the influence of an evolving dark sector on the formation and evolution of structure in the Universe, and for that we need numerical simulations.

Now, these simulations are not easy. To get enough resolution, you need to run them on supercomputers, and you also need to be careful that you have correctly included the required physics. And that's what we have. The goal of this second paper is to ask the question "How does an evolving dark sector influence the number and properties of galaxy clusters in the Universe?"

Galaxy clusters are the biggest agglomerations of mass in the Universe, so they are easy to find in our simulations. 

As I mentioned, the interacting dark sector has to be quite subtle (or we would have worked out its properties by now) and in terms of the number of clusters we have in our range of universes with a specific mass, the interacting models seem no different to the standard cosmological models.
When we start to look at the more detailed properties of the clusters, such as how the baryons (i.e. atoms) are distributed, we find there are subtle differences.
We can see these baryons in clusters as a hot gas surrounding the galaxies, so this could be a potential probe of the true goings-on in the dark sector.

We do look at other properties of the clusters, their spins and alignments, and while there are differences, they are small and would he hard to discern observationally.

But now we have our new software for generating synthetic universes, the goal will be to push the resolution higher and higher, to uncover individual galaxies like our own Milky Way. There will definitely be new results on the nature of the dark sector, so watch this space. 

Well done Edoardo!

Hydrodynamical simulations of coupled and uncoupled quintessence models II: Galaxy clusters

We study the z=0 properties of clusters (and large groups) of galaxies within the context of interacting and non-interacting quintessence cosmological models, using a series of adiabatic SPH simulations. Initially, we examine the average properties of groups and clusters, quantifying their differences in LCDM, uncoupled Dark Energy (\ude) and coupled Dark Energy (\cde) cosmologies. In particular, we focus upon radial profiles of the gas density, temperature and pressure, and we also investigate how the standard hydrodynamic equilibrium hypothesis holds in quintessence cosmologies. While we are able to confirm previous results about the distribution of baryons, we also find that the main discrepancy (with differences up to 20%) can be seen in cluster pressure profiles. We then switch attention to individual structures, mapping each halo in quintessence cosmology to its \LCDM\ counterpart. We are able to identify a series of small correlations between the coupling in the dark sector and halo spin, triaxiality and virialization ratio. When looking at spin and virialization of dark matter haloes, we find a weak (5%) but systematic deviation in fifth force scenarios from \LCDM.

Wednesday, 5 February 2014

Can we see objects moving faster than the speed of light?

I'm a big fan of Derek Muller's youtube channel Veritasium. It discusses lots of cool scientific topics, and presents a deep understanding of the underlying physics in a fun and entertaining manner. His most recent video asks the question "Will this go faster than light?", looking at ways of failing to break the Universal Speed Limit.

Right at the end, Derek discusses the speed of light in a cosmological context, and mentions that out in the expanding Universe, there are galaxies that are moving away from us faster than light, which he then goes onto say that we can't see because of their speed.

Is this correct? Derek is in good company, as lots of renowned physicists have made similar comments; here's Richard Feynman (taken from this great article which I very much recommend if you are interested in this topic).
But alas, even the great Feynman can be wrong.

Want to see something moving faster than light? Here you go.
This, of course, is the Cosmic Microwave Background, and the bits and pieces that emitted the radiation which we are now receiving were moving faster than the speed of light, relative to us, when it was emitted. (In the following, it should be noted that coordinates and distances in cosmology are complicated things, and so the picture is a little messier than I let on).

It's easiest to understand this with one of my favourite pictures from Tamara Davis - it represents the expansion of the Universe in conformal coordinates, in which light-rays travel at 45 degrees.
Just to remind you, we're at the middle, and the line from the top to bottom is the complete history. In these cool coordinates, the big bang is at the bottom and the infinite future is at the top; the way the coordinates work is to pull the infinite time in the future to a finite value.

"Now" is the blue horizontal line, so here-today is where the blue line crosses the middle vertical line (this is starting to sound like the mildly mind-bending time travel of Asimov's The End of Eternity).

The red line is our current past light cone; the light of everything we see now was emitted on this line.

The purple large tear-drop is the Hubble Sphere, which splits objects in the Universe into those moving away from us less than the speed of light from those moving faster than the speed of light due to the expansion of space. Those objects in the white region are the subluminal objects. Everything else is superluminal with respect to us.

As you can see, the red line passes through the white region, so all the objects on this line were moving slower than light when the light was emitted, but those in the yellow were moving faster than light. The cosmic microwave background comes from a few hundred thousand years after the Big Bang, so from the bottom of the picture, and so the emitters were traveling faster than light when the radiation was emitted.

But clearly lots of the Universe was. Lots of object in the Hubble Deep Field....
were moving away from us at faster than the speed of light when the light was emitted. How cool is that?

This might make you scratch your head a little. But how? I suggest you have a read of this paper, but basically, the journey of light through the Universe is complicated by how space has expanded over cosmic history, and just because an object is moving faster than light when the radiation was emitted does not necessary mean you can't see it.

One last question - Are there objects moving at faster than the speed of light NOW that we will see in the future? Again, the answer is yes. Let's zoom in on the above figure.
We're at zero, and the dotted vertical line is our infinite future. Blue is today and purple is Hubble Sphere. Again, those in white are moving slower than the speed of light, and those beyond are moving faster.

Remembering that light rays travel at 45 degrees in these coordinates, in the future we can construct a past light cone that hits the yellow region today, so there are objects moving faster than the speed of light today that we will see in the future.

The orange line is our ultimate light cone, our future event horizon, which separates events that we can see from those we don't. This has major implications for what we will see in the future, but means that the Universe will become a dark, cold place. But there are things that need to be done, so more on that later.