## Wednesday, October 28, 2015

### Change of scenery

I should have reported this a while ago, but better late than never: I have moved to a new job, at a new institution, in a new country. In fact since the 1st of October this year I have been employed by the Institute for Cosmology and Gravitation at the University of Portsmouth, where I now hold a Marie Skłodowska-Curie individual fellowship and the ICG's Dennis Sciama fellowship (though unfortunately I do not get paid two salaries at once!).

It's partly a sign of how much I have been neglecting this blog in recent times that I've only just got around to posting about this now, nearly a month after arriving here. But it is also partly due to the fact that I am still waiting for a functioning internet connection in my new home, so any blog postings must be done while still at my desk!

Anyway, I'm very excited to be working here at the ICG, because it is one of the leading cosmology institutes in the UK, and therefore by extension in Europe and also the world. The institute directors mentioned several times during staff induction meetings the statistics for how much of the research output here was graded "world-leading" or "internationally excellent" in the recent UK REF review — but I forget the numbers. In any case what's more important is that the ICG is home to world experts in many of the fields that I work in, and — crucially — that it is a very large, exciting and young department, with around 60 members, of whom 20 or so (20!) are young postdoctoral researchers, and another 20 are PhD students.

Since I like including pictures with my posts, let me put some up of the famous names associated with my fellowships. Here is Marie Curie, from her 1903 Nobel Prize portrait:

 "Marie Curie 1903" by the Nobel foundation. (Public domain)
and here is Dennis Sciama:

Marie Curie is of course justly famous around the world and I'm sure everyone reading this blog is aware of her fantastic achievements — two Nobel prizes, in two different sciences, first woman to win a Nobel prize, discoverer of two elements, the theory of radioactivity, and so on.

Dennis Sciama is perhaps not quite so well known to those outside cosmology, but my what a towering figure he is within the field, and in the history of British science. Even the list of his PhD students reads like a who's-who of modern cosmology: Stephen Hawking, Martin Rees, George Ellis, Gary Gibbons, John Barrow, James Binney ...

The ICG in particular seems to have rather a fondness for Sciama — in addition to the fellowship I've already mentioned, we work in the Dennis Sciama building, and many of us make use of the SCIAMA supercomputer. I was a little puzzled by this, because although Sciama moved from Cambridge to Oxford to Trieste during his career, I wasn't aware of any special link to Portsmouth.

In fact the answer appears to be that a large proportion of the staff at the ICG happened to be (academically speaking) his grandchildren, having received the PhDs under the supervision of George Ellis or John Barrow. That, and the fact that it is always nice to name new buildings after really famous people!

Anyway, this will hopefully mark the start of a rather more regular series of posts about cosmology here — for one thing, my Marie Curie proposal included a proposal included a commitment to write short explanations of each new paper I produce over the next two years!

PS: A small factoid that caught my attention about Dennis Sciama is that although born in Manchester, his family was actually of Syrian Jewish origin. They originally came from Aleppo, in fact, though his mother was born in Egypt. In light of recent events it seems worth pondering on that.

## Thursday, September 17, 2015

### 10 tips for making postdoc applications (Part 2)

This post is part 2 of a series with unsolicited advice for postdoc applicants. Part 1, which includes a description of the motivation behind the posts and tips 1 through 5, can be found here.

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### 6. Promote yourself

This sounds sort of obvious, but for cultural reasons may come easier to some people than to others. I don't mean to suggest you should be boastful or oversell yourself in your CV and research statement. But be aware that people reading through hundreds of applications will not have time to read between the lines to discover your unstated accomplishments — so present the information that supports your application as clearly and as matter-of-factly as possible.

As a very junior member of the academic hierarchy, it is quite likely that nobody in the hiring department has heard of you or read any of your papers, no matter how good they were. They are far more likely to recognise your name if you happen to have taken some steps make yourself known to them, for instance by having arranged a research visit, given a talk at their local journal club or seminar series, initiated a collaboration on topics of mutual interest, or simply introduced yourself and your research at some recent conference.

Organisers of seminar series and journal clubs are generally more than happy to have volunteers help fill some speaking slots — put anxieties to one side and just email them to ask! And if they do have time for you, make sure you give a good talk.

### 7. Know what type of postdoc you're applying for

There are, roughly speaking, three different categories of postdoc positions in high-energy and astro (and probably more generally in all fields of physics, if not in all sciences).

The first category is fellowships. These are positions which provide funding to the successful candidate to pursue a largely independent line of research. They therefore require you to propose a detailed and interesting research plan. They may sometimes be tied to a particular institution, but often they provide an external pot of money that you will be bringing to the department you go to. They are also highly prestigious. Examples applicable to a cosmology context are Hubble and Einstein fellowships in the US, CITA national fellowships in Canada, Royal Society and Royal Astronomical Society fellowships in the UK, Humboldt fellowships in Germany, Marie Skłodowska-Curie fellowships across Europe, and many others.

The second category is roughly a research assistant type of position. Here you are hired by some senior person who has won a grant for their research proposal, or has some other source of funding out of which to pay your salary. You are expected to work on their research project, in a pretty closely defined role.

The third category is a sort of mix of the above two, which I'll call a semi-independent postdoc. This is where the postdoc funding comes from someone's grant, but they do not specify a particular research programme at the outset, giving you a large degree of independence in what work you actually want to do.

 Image credit: Jorge Cham.

When you apply, it is imperative that you know which of these three types of positions the people hiring you have in mind. There is no point trying to sell a detailed independent research plan — no matter how exciting — to someone who is only interested in whether you have the specific skills and experience to do what they tell you to. Equally, if what they want is evidence that you will drive research in your own directions, an application that lists your technical skills but doesn't present a coherent plan of what you will do with them is no good.

Unfortunately postdoc ads don't use these terms, so it is generally not clear whether the position is of the second or third type. If in doubt, contact the department and find out what they want.

Also, even when the distinction may be clear, many people still produce the same type of application for all jobs they apply for in one cycle. I know of an instance of a highly successful young scientist who managed to win not one but two prestigious individual fellowship grants worth hundreds of thousands of Euros each, and yet did not get a single offer from any of non-fellowship positions they applied to! So tailor your applications to the situation.

### 8. Apply for fellowships

Applications for the more prestigious fellowships require more work — a lot more work — than other postdoc applications. They will require you to produce a proper research proposal, which will need to include a clear and inspiring outline — of anything between one and twenty pages length — of what you intend to do with the fellowship. This will take a long time to think of and longer to write. They will probably require you to work on the application in collaboration with your host department, and they may have a million other specifically-sized hoops for you to jump through.

Nevertheless, you should make a serious attempt to apply for them, for the following reasons.

• Any kind of successful academic career requires you to write lots of such proposals, so you might as well start practising now.
• Writing a proposal forces you to prepare a serious plan of what research you want to do over the next few years, which will help clarify a lot of things in your mind, including how much you actually want to stay in the field (see point 2 again!).
• You will often write the proposal in collaboration with your potential host department. This makes it far more likely that they will think favourably of you should any other opportunities arise there later! For instance, I know of many cases where applicants for Marie Curie fellowships have ended up with positions in the department of their choice even though the fellowship application itself was ultimately unsuccessful.
• Major fellowship programmes are more likely to have the resources and the procedures in place to thoroughly evaluate each proposal, reducing the unfortunate random element I'll talk about below. Many will provide individual feedback and assessments, which will help you if you reapply next year.
• Counter-intuitively, success rates may be significantly higher for major fellowships than for standard postdoc jobs! Last year, the success rate for Hubble fellowships was 5%, for Einstein fellowships 6%, and for Marie Curie fellowships (over all fields of physics) almost 18%. All of these numbers compare quite well with those for standard postdoc positions! Granted, this is at least partly due to self-selection by applicants who don't think they can prepare a good enough proposal in the first place, but it is still something to bear in mind.
• Obviously, a successful fellowship application counts for a lot more in advancing your career than a standard postdoc.

### 9. Recognize the randomness

Potential employers are faced with a very large number of applications for each postdoc vacancy; a ratio of 100:1 is not uncommon. Even with the best of intentions, it is just not possible to give each application equal careful consideration, so some basic pre-filtering is inevitable.

Unfortunately for you, each department will have its own criteria for pre-filtering, and you do not know what those criteria are. Some will filter on recommendation letters, some on number of publications, some on number of citations. (As a PhD student I was advised by a well-meaning faculty member at a leading UK university that although they found my research very interesting, I did not yet meet their cutoff of X citations for hiring postdocs.) Others may deduce your field of interest only from existing publications rather than your research statement — this is particularly hard on recent PhDs who may be trying to broaden their horizons beyond their advisor's influence.

Beyond this, it's doubtful that two people in different departments will have the same opinion of a given application anyway. They're only human, and their assessments will always be coloured by their own research interests, their plans for the future of the department, their different personal relationships with the writers of your recommendation letters, maybe even what they had for breakfast that morning.

You can't control any of this. Your job is to produce as good and complete an application as possible (remember to send everything they ask for!), to apply to lots of suitable places, and then to learn not to fret.

### 10. Don't tie your self-esteem to the outcome

You will get rejections. Many of them. Even worse, there will be many places who don't even bother to let you know you were rejected. You will sometimes get a rejection at the exact same time as someone else you know gets an offer, possibly for the same position. (Things are made worse if you read the postdoc rumour mills regularly.)

It's pretty hard to prevent these rejections from affecting you. It's all too easy to see them as a judgement of your scientific worth, or to develop a form of imposter syndrome. Don't do this! Read point 9 again.

I'd also highly recommend reading this post by Renée Hlozek, which deals with many of the same issues. (Renée is one of the rising stars of cosmology, with a new faculty position after a very prestigious postdoc fellowship, but she too got multiple rejections the first time she applied. So it does happen to the best too, though people rarely tell you that.)

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That's it for my 10 tips on applying for (physics) postdocs. They were written primarily as advice I would have liked to have given my former self at the time I was completing my PhD.

There's plenty of other advice available elsewhere on the web, some of it good and some not so good. I personally felt that far too much of it concerned how to choose the best of multiple offers, which is both a bit pointless (if you've got so many offers you'll be fine either way) and really quite far removed from the experience of the vast majority of applicants. I hope some people find this a little more useful.

## Sunday, September 13, 2015

### 10 tips for making postdoc applications (Part 1)

Around this time of year in the academic cycle, thousands of graduate students around the world will be starting to apply for a limited supply of short-term postdoctoral research positions, or 'postdocs'. They will not only be competing against each other, but also slightly more senior colleagues applying for their second or possibly third or fourth postdocs.

The lucky minority who are successful — and, as Richie Benaud once said about cricket captaincy, it is a matter of 90% luck and 10% skill, but don't try it without the 10% — will probably need to move their entire life and family to a new city, country or continent. The entire application cycle can last two or three months — or much longer for those who are not successful in the first round — and is by far the most stressful part of an early academic career.

What I'd like to do here is to provide some unsolicited advice on how best to approach the application process, which I hope will be of help to people starting out on it. This advice mostly consists of a collection of things that I wish people had told me when I was starting out myself, plus things that people did tell me, but that for whatever reason I didn't understand or appreciate.

My own application experience has been in the overlapping fields of cosmology, astrophysics and high-energy particle physics, and most of my advice is written with these fields in mind. Some points are likely to be more generally useful, but I don't promise anything!

I'm also not going to claim to know much about what types of things hiring professors or committees actually look for — in fact, I strongly suspect that there are very few useful generalizations that can be made which cover all types of jobs and departments. So I won't tell you what to wear for an interview, or what font to use in your CV. Instead I'll try to focus on things that might help make the application process a bit less stressful for you, the applicant, giving you a better chance of coming out the other side still happy, sane, and excited about science.

With that preamble out of the way, here are the first 5 of my tips for applying for postdocs! The next 5 follow in part 2 of this post.

### 1. Start early

At least in the high-energy and astro fields, the way the postdoc job market works means that for the vast majority of jobs starting in September or October of a given year, the application deadlines fall around September to October of the previous year. Sometimes — particularly for positions at European universities — the deadlines may be a month or two later. However, for most available positions job offers are made around Christmas or early in the new year, and the number of positions still advertised after about February is small to start with and decreases fast with each additional month.

This means if you want to start a postdoc in 2016, you should already have started preparing your application materials. If not, it's not too late, but start immediately!

Applying for research jobs is a very different type of activity to doing research, is not as interesting, requires learning a different set of skills, and therefore can be quite daunting. This makes it all too easy to procrastinate and put it off! In my first application cycle, I came up with a whole lot of excuses and didn't get around to seriously applying for anything until at least December, which is way too late.

### 2. Consider other options

This sounds a bit harsh, but I think it is vital. My point is not that getting into academia is a bad career move, necessarily. But don't get into it out of inertia. I've met a few people who, far too many months into the application cycle, with their funding due to run out, and despite scores of rejections, continue the desperate search for a postdoc position somewhere, anywhere, simply because they cannot imagine what else they might do.

Don't be that person. There are lots of cool things you can do even if you don't get a postdoc. There are many other interesting and fulfilling careers out there, which will provide greater security, won't require constant upheaval, and will almost certainly pay better. Many of them still require the kinds of skills we've spent so many years learning — problem solving, tricky mathematics, cool bits of coding, data analysis — but most projects outside academia will be shorter and less nebulous, success will be more quantifiable and the benefits of success may well be more tangible.

If you have no idea what kinds of jobs you could do outside academia, find out now. Get in touch with previous graduate students from your department who went that way, find out what they are doing and how they got there. The AstroBetter website provides a great collection of career profiles which may provide inspiration.

If after examining the alternatives you decide you'd still prefer that postdoc, great. But at least when you apply you won't be doing it purely out of inertia, and you'll have the reassurance that if you don't get it, there are other cool things you could do instead. And I'm pretty sure this will help your peace of mind during the weeks or months you spend re-drafting those research statements!

 Image credit: Jorge Cham.

### 3. Apply everywhere

It's not uncommon in physics for some postdoc ads to attract 100 qualified applicants or more per available position, and the numbers of advertised positions isn't that large. So apply for as many as you can! It's not a great idea to decide where to apply based on 'extraneous' reasons — e.g., you only want to live in California or Finland or some such.

Particularly if you're starting within Europe, you will probably have to move to a new country, and probably another new country after that. So if you have a strong aversion to moving countries, I'd suggest going back to point 2 above.

On the other hand, you can and should take a more positive view: living somewhere new, learning a new language and discovering a new culture and cuisine can be tremendous fun! Even remote places you've never heard of, or places you think you might not like, can provide you with some of the best memories of your life. Just as small example, before I moved to Helsinki, my mental image of Finland was composed of endless dark, depressing winter. After two years here this image has been converted instead to one of summers of endless sunshine and beautiful days spent at the beach! (Disclaimer: of course Finland is also dark, cold and miserable sometimes. Especially November.)

So for every advertised position, unless you are absolutely 100% certain that you would rather quit academia than move there for a few years — don't think about it, just apply. For the others, think about it and then apply anyway. If you get offered the job you'll always be able to say no later.

### 4. Don't apply everywhere

However, life is short. Every day you spend drafting a statement telling people what great research you would do if they hired you is a day spent not doing research, or indeed anything else. If you apply for upwards of 50 different postdoc jobs (not an uncommon number!), all that time adds up.

So don't waste it. Read the job advertisement carefully, and assess your chances realistically. There's not much to be gained from applying to departments which are not a good academic fit for you.

When I first applied for postdocs several years ago, I would read an advert that said something like "members of the faculty in Department X have interests in, among other things, string theory, lattice QCD, high-temperature phase transitions, multiloop scattering amplitudes, collider phenomenology, BSM physics, and cosmology," and I'd focus on those two words "and cosmology". So despite knowing that "cosmology" is a very broad term that can mean different things to different people, and despite not being qualified to work on string theory, lattice QCD, high-temperature phase transitions etc., I'd send off my application talking about analysis of CMB data, galaxy redshift surveys and so on, optimistically reasoning that "they said they were interested in cosmology!" And then I'd never hear back from them.

Nowadays, my rule of thumb would be this: look through the list of faculty, and if it doesn't contain at least one or two people whose recent papers you have read carefully (not just skimmed the abstract!) because they intersected closely with your own work, don't bother applying. If you don't know them, they almost certainly won't know you. And if they don't know you or your work, your application probably won't even make it past the first round of sorting — faced with potentially hundreds of applicants, they won't even get around to reading your carefully crafted research statement or your glowing references.

Being selective in where you apply will save you a heap of time, allow you to produce better applications for the places which really do fit your profile, and most importantly leave you feeling a lot less jaded and disillusioned at the end of the process.

### 5. Choose your recommendations well

Almost all postdoc adverts ask for three letters of recommendation in addition to research plans and CVs. These letters will probably play a crucial part in the success of your application. Indeed for a lot of PhD students applying for their first postdoc, the decision to hire is based almost entirely on the recommendation letters - there's not much of an existing track record by this stage, after all.

So it's important to choose well when asking senior people to write these recommendation for you. As a graduate student, your thesis advisor has to be one of them. It helps if one of the others is from a different university to yours. If possible, all three should be people you have worked, or are working, closely with, e.g. coauthors. But if this is not possible, one of the three could also be a well-known person in the field who knows your work and can comment on its merit and significance in the literature.

Having said that, there are several other factors that go into choosing who to get recommendations from. Some professors are much better at supporting and promoting their students and postdocs in the job market than others. You'll notice these people at conferences and seminars: in their talks they will go out of their way to praise and give credit to the students who obtained the results they are presenting, whereas others might not bother. These people will likely write more helpful recommendations; they also generally provide excellent career advice, and may well help your application in other, less obvious, ways. They are the ideal mentors, and all other things being equal, their students typically fare much better at getting that first and all-important step on the postdoc ladder. Of course ideally your thesis advisor will be such a person, but if not, find someone in your department who is and ask them for help.

Somewhat unfortunately, I'm convinced that how well your referees themselves are known in the department to which you are applying is almost as important as how much they praise you. If neither you nor any of your referees have links — previous collaborations, research visits, invitations to give seminars — with members of the advertising department, I think the chances of your application receiving the fullest consideration are unfortunately much smaller. (I realise this is a cynical view and having never been on a hiring committee myself I have no more than anecdotal evidence in support of it. But I do see which postdocs get hired where.) So choose wisely.

It is also a good idea to talk frankly to your professors/advisor beforehand. Explain where you are planning to apply, what they are looking for, and what aspects of your research skills you would like their letters to emphasise. Get their advice, but also provide your own input. You don't want to end up with a research statement saying you're interested in working in field A, while your recommendations only talk about your contributions in field B.

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That's it for part 1 of this lot of unsolicited advice. Part 2 is available here!

## Sunday, April 26, 2015

### Supervoid superhype, or the publicity problem in science

Part of the reason this blog has been quiet recently is that I decided at the start of this year to try to avoid — as far as possible — purely negative comments on incorrect, overhyped papers, and focus only on positive developments. (The other part of the reason is that I am working too hard on other things.)

Unfortunately, last week a cosmology story hit the headlines that is so blatantly incorrect and yet so unashamedly marketed to the press that I'm afraid I am going to have to change that stance. This is the story that a team of astronomers led by Istvan Szapudi of the University of Hawaii have found "the largest structure in the Universe", which is a "huge hole" or "supervoid" that "solves the cosmic mystery" of the CMB Cold Spot. This story was covered by all the major UK daily news outlets last week, from the Guardian to the Daily Mail to the BBC, and has been reproduced in various forms in all sorts of science blogs around the world.

There are only three things in these headlines that I disagree with: that this thing is a "structure", that it is the largest in the Universe, and that it solves the Cold Spot mystery.

Let's focus on the last of these. Readers of this blog may remember that I wrote about the Cold Spot mystery in August last year, referring to a paper my collaborators and I had written which conclusively showed that this very same supervoid could not explain the mystery. Our paper was published back in November in Phys. Rev. D (journal link, arXiv link). And yet here we are six months later, with the same claims being repeated!

Does the paper by Szapudi et al. (journal link, arXiv link) refute the analysis in our paper? Does it even acknowledge the results in our paper? No, it pretends this analysis does not exist and makes the claims anyway.

Just to be clear, it's possible that Szapudi's team are unaware of our paper and the fact that it directly challenged their conclusions several months before their own paper was published, even though Phys. Rev. D is a very high profile journal. This is sad and would reflect a serious failure on their part and that of the referees. The only alternative explanation would be that they were aware of it but chose not to even acknowledge it, let alone attempt to address the argument within it. This would be so ethically inexcusable that I am sure it cannot be correct.

I am also frankly amazed at the standard of refereeing which I'm afraid reflects extremely poorly on the journal, MNRAS.

Coming to the details. In our paper last year, we made the following points:
1. Unless our understanding of general relativity in general, and the $\Lambda$CDM cosmological model in particular, is completely wrong, this particular supervoid, which is large but only has at most 20% less matter than average, is completely incapable of explaining the temperature profile of the Cold Spot.
2. Unless our understanding is completely wrong as above, the kind of supervoid that could begin to explain the Cold Spot is incredibly unlikely to exist — the chances are about 1:1,000,000!
3. The corresponding chances that the Cold Spot is simply a random fluctuation that requires no special explanation are at worst 1:1000, and, depending on how you analyse the question, probably a lot better.
4. This particular supervoid is big and rare, but not extremely so. In fact several voids that are as big or bigger, and as much as 4 times emptier, have already been seen elsewhere in the sky, and theory and simulation both suggest there could be as many as 20 of them.
To illustrate point 1 graphically, I made the following figure showing the actual averaged temperature profile of the Cold Spot versus the prediction from this supervoid:

If this counts as a "solution to a cosmic mystery" then I'm Stephen Hawking.

The supervoid can only account for less than 10% of the total temperature decrement at the centre of the Cold Spot (angle of $0^\circ$). At other angles it does worse, failing to even predict the correct sign! And remember, this prediction only assumes that our current understanding of cosmology is not completely, drastically wrong in some way that has somehow escaped our attention until now.

You'll also notice that if the entire red line is somehow magically (through hypothetical "modified gravity effects") scaled down to match the blue line at the centre, it remains wildly, wildly wrong at every other angle. This is a direct consequence of the fact that the supervoid is very large, but really not very empty at all.

By contrast, the simple fact that the Cold Spot is chosen to be the coldest spot in the entire CMB already accounts for 100% of the cold temperature at the centre:

 The red line is the observed Cold Spot temperature profile. 95% 68% of the coldest spots chosen in random CMB maps have temperatures lying within the dark blue band, and 99% 95% lie within the light blue band. Image credit: http://arxiv.org/abs/1408.4720.

Similarly, the fact that Mt. Everest is much higher than sea level is not at all surprising. The highest mountains on other planets (Mars, for instance) can be a lot higher still.

But how to explain the fact that a large void does appear to lie in the same direction as the Cold Spot? Is this not a huge coincidence that should be telling us something?

Let's try the following calculation. Take the hypothesis that this particular void is causing the Cold Spot, let's call it hypothesis H1. Denote the probability that this void exists by $p_\mathrm{void}$, and the probability that all of GR is wrong and that some unknown physics leads to a causal relationship as $p_\mathrm{noGR}$. Then
$$p_\mathrm{H1}=p_\mathrm{void}p_\mathrm{noGR}$$On the other hand, let H2 be the hypothesis that the void and the Cold Spot are separate rare occurrences that happen by chance to be aligned on the sky. This gives
p_\mathrm{H2}=p_\mathrm{void}p_\mathrm{CS}p_\mathrm{align},where $p_\mathrm{CS}$ is the probability that the Cold Spot is a random fluctuation on the last scattering surface, and p_\mathrm{align} the probability that two are aligned.

The relative likelihood of the two rival hypotheses is given by the ratio of the probabilities:
\frac{p_\mathrm{H1}}{p_\mathrm{H2}}=\frac{p_\mathrm{noGR}}{p_\mathrm{CS}p_\mathrm{align}}.Suppose we assume that $p_\mathrm{CS}=0.05$, and that the chance of alignment at random is p_\mathrm{align}=0.001.[1] Then the likelihood we should assign to "supervoid-caused-the-Cold-Spot" hypothesis depends on whether we think $p_\mathrm{noGR}$ is more or less than 1 in 20,000.

This exact calculation appears in Szapudi et al's paper, except that they mysteriously leave out the numerator on the right hand side. This means that they assume, with probability 1, that general relativity is wrong and that some unknown cause exists which makes a void with only a 20% deficit of matter create a massive temperature effect. In other words, they've effectively assumed their conclusion in advance.

Well, call me old-fashioned, but I don't think that makes any sense. We have a vast abundance of evidence, gathered over the last 100 years, which show that if indeed GR is not the correct theory of gravity it is still pretty damn close to it. What's more, we have lots of cosmological evidence — from the Planck CMB data, from cross-correlation measurements of the ISW effect, as well as from weak lensing — that gravity behaves very much as we think it does on cosmological scales. Looking at the figure above, for the supervoid to explain the Cold Spot requires at least a factor of 10 increase in the ISW effect at the void centre, as well as a dramatic effect on the shape of the temperature profile. And all this for a void with only a 20% deficit of matter! If the ISW effect truly behaved like this we would have seen evidence of it in other data.

For my money, I would put $p_\mathrm{noGR}$ at no higher than $2.9\times10^{-7}$, i.e. I would rule out the possibility at $5\sigma$ confidence. This is a lot less than 1:20,000, so I would say chance alignment is strongly favoured. Of course you should feel free to put your own weight on the validity of all of the foundations of modern cosmology, but I suggest you would be very foolish indeed to think, as Szapudi et al. seem to do, that it is absolutely certain that these foundations are wrong.

So much for the science, such as it is. The sociological observation that this episode brings me back to is that, almost without exception, whenever a paper on astronomy or cosmology is accompanied by a big press release, either the science is flawed, or the claims in the press release bear no relation to the contents of the paper. This is a particularly blatant example, where the authors have generated a big splash by ignoring (or being unaware of) existing scientific literature that runs contrary to their argument. But the phenomenon is much more ubiquitous than this.

I find this deeply depressing. Like most other young researchers (I hope), I entered science with the naive impression that what counted in this business was the accuracy and quality of research, the presentation of evidence, and — in short — facts. I thought the scientific method would ensure that papers would be rigorously peer-reviewed. I did not expect that how seriously different results are taken would instead depend on the seniority of the lead author and the slickness of their PR machine. Do we now need to hold press conferences every time we publish a paper just to get our colleagues to cite our work?

One possible response to this is that I was hopelessly naive, so more fool me. Another, which I still hope is closer to the truth, is that, in the long run, the crap gets weeded out and that truth eventually prevails. But in an era when public "impact" of scientific research is an important criterion for career advancement, and such impact can be simply achieved by getting the media to hype up nonsense papers [2], I am sadly rather more skeptical of the integrity of scientists [3].
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[1] This probability for alignment is the number quoted by Szapudi's team, based on the assumption that there is only one such supervoid, which could be anywhere in the sky. In fact, as I've already said, theory and simulation suggest there should be as many as 20 supervoids, and several have already been seen elsewhere in the sky (including one other by Szapudi's team themselves!). The probability that any one supervoid should be aligned with the Cold Spot should therefore be roughly 20 times larger, or 0.02.

[2] Not everything in Szapudi's paper is nonsense, of course. For instance, it seems quite likely that there is indeed a large underdensity where they say. But there is still a deal of nonsense (described above) in the actual paper, and vastly more in the press releases, especially the one from the Institute for Astronomy in Hawaii.

[3] On the whole, given the circumstances I though journalists handled the hype quite well, especially Hannah Devlin in the Guardian, who included a skeptical take from Carlos Frenk. (I suspect Carlos at least was aware of our paper!)