B-modes, rumours, and inflation

Update: The announcement will definitely be about a major discovery by BICEP2, meaning it can only really be about a B-mode signal. You can follow the webcast at  http://www.cfa.harvard.edu/news/news_conferences.html, starting at 10:45 am EDT (14:45 GMT) for scientists, or 12:00 pm EDT (16:00 GMT) for the general public and news organisations.

The big news in cosmology circles at the minute is the rumour that the "major discovery" due to be announced at a press conference on Monday the 17th is in fact a claimed detection of the B-mode signal in the CMB by the the BICEP2 experiment.

Now, I'm not particularly well placed to comment on this rumour, since all the information I have comes at second- or third-hand, via people who have heard something from someone, people who think they heard something from someone, or people who are simply unashamedly speculating. (Perhaps this is a function of being on the wrong side of the Atlantic: although the BICEP2 experiment is based at the South Pole, the only non-North-American university participating in the collaboration is Cardiff University in Wales. Even worse, I'm not on Twitter.) In any case, by reading this, this, this and this, you will be starting with essentially the same information as me.

But having got that health warning out of the way, let's pretend that the rumours are entirely accurate and that on Monday we will have an announcement of a detection of a significant B-mode signal. What would this mean for cosmology?

Firstly, the B-mode signal refers to a particular polarisation of the CMB (for a short and somewhat technical introduction, see here; for a slightly longer one, see here). This polarisation can arise in various ways, one of which is the polarisation induced in the CMB by gravitational lensing, as the CMB photons travel through the inhomogeneous Universe on their way from the last scattering surface to us. There have been a few experiments, such as POLARBEAR, which have already claimed a detection of this lensing contribution to the B-mode signal (though in this particular case after skim-reading the paper I was a little underwhelmed by the claim).

Now, detecting a lensing B-mode would be cool, but significantly less exciting than detecting a primordial B-mode. This is because whereas the lensing signal comes from late-time physics that is quite well understood, a primordial signal would be evidence of primordial tensor fluctuations or primordial gravitational waves. And this is cool because inflation provides a possible way to produce primordial gravitational waves – therefore their detection could be a major piece of evidence in favour of inflation.

The contributions to the B-mode signal coming from gravitational waves and lensing are differentiated on the basis of the multipoles (essentially the length scale) at which they are important. Figure from Hu and Dodelson 2002.

People often say that detection of this tensor signal would be a "smoking gun" for inflation; something that would be very welcome, because although inflation has proved to be an attractive and fertile paradigm for cosmology, there is still a bit of a lack of direct, incontrovertible evidence in favour of it. Coupled with certain unresolved theoretical issues it faces, this lack of a smoking gun meant that arguments for or against inflation were threatening to degenerate into what you might call "multiverse territory", definitely an unhealthy place to be.

It may be worth introducing a note of caution about this "smoking gun" though. Although inflation is a possible source of primordial gravitational waves, it is not the only one. Artefacts of possible phase transitions in the early universe, known as cosmic defects, can also produce a spectrum of gravitational waves – and what's more, this spectrum can be exactly scale-invariant, just as that from inflation. I don't know a huge amount about this field, so I am not sure whether the amplitude of the perturbations which could be produced by these cosmic defects could be sufficiently large, nor – if it is – whether there are any other features which could help distinguish this scenario from inflation if the rumours turn out to be true. Perhaps better informed people could comment below.

Suppose we put that issue to one side though, and assume that not only has a significant tensor signal been detected, we have also been able to prove that it could not be due to anything other than inflation. The rumour is that the detection corresponds to value for the tensor-to-scalar ratio r of about 0.2. What are the implications of this for the different inflation models?

Planck limits on various inflationary models.

Not all models of inflation do result in tensor modes large enough to observed in the CMB, so an observation of a large r would rule out a large class of these models. Generally speaking, the understanding is that models in which the inflaton field $\phi$ takes large values (i.e., values larger than the Planck mass $M_P$) are the ones which could produce observably large r, whereas the so-called "small-field models" where $\phi\ll M_P$ usually predict tiny values of r which could never be observed. (A note for non-experts: irrespective of the field value, the energy scale in both small-field and large-field models is always much less than the Planck scale.) Therefore, at a stroke, all small-field inflation models would be ruled out. Many people regard these as the better-motivated models of inflation, with in some respects fewer theoretical issues than the large-field models, so this would be quite significant.

There are two small caveats to this statement: firstly, it isn't strictly necessary for $\phi$ itself to be larger than $M_P$ to generate a large r, only that the change in $\phi$ be large. So models in which the inflaton field winds around a cylinder, in effect travelling a large distance without actually getting anywhere, can still give large r (hat-tip to Shaun for that phrasing). Also, it is not even strictly true that the change in $\phi$ must be large: if some other rather specific conditions (including the temporary breakdown of the slow-roll approximation) are met, this one can be avoided and even small field models can produce enough gravitational waves. This was something pointed out by a paper I wrote with Shaun Hotchkiss and Anupam Mazumdar in 2011, though other people had similar ideas at about the same time. Such rather forced small-field models would have other specific features though, so could be distinguished by other measurements.

One of the more interesting consequences of a detection of large r (aside from the earth-shattering importance of a confirmation of inflation itself) would be that the Higgs inflation model – which has been steadily gaining in popularity given the results from the LHC and Planck, and has begun to be regarded by many as the most plausible mechanism by which inflation could have occurred – would be disfavoured. In the plot above, the Higgs inflation prediction is shown by the orange points at the bottom centre of the figure. So a BICEP2 detection of $r\sim0.2$ as suggested by the rumours would be pretty serious for this model.

On the other hand, a BICEP2 detection of $r\sim0.2$ would also strongly contradict appear to be at odds with the results from the Planck and WMAP satellites. Which probably goes to show that there is not much point believing every rumour ...

We will find out on Monday!

Unnecessary spin

A few people have asked me why I have not blogged about the recent announcement about, and publication of, results from the Alpha Magnetic Spectrometer, which were widely touted as a possible breakthrough in the search for dark matter.

The reason I have not is simply that there are many other better informed commenters who have already done so. In case you have not yet read these accounts, you could do worse than going to Résonaances, or Ethan Siegel, or Stuart Clark in the Guardian, who provide commentary at different levels of technical detail. The simple short summary would be: AMS has not provided evidence about the nature of dark matter, nor is it likely to do so in the near future. The dramatic claims to the contrary are spin, pure and simple. Siegel in fact goes so far as to say "calling it misleading is generous, because I personally believe it is deceitful" (emphasis his own).

So I'm not going to make any more comments about that.

However, since this incident brought it up again, I do want to comment on a related piece of annoying spin, which is the habit of physicists in the business of communicating science to the public of making vastly exaggerated claims about the possible practical applications of fundamental physics. The example that caught my attention this week occurred when Maggie Aderin-Pocock – who is apparently a space science research fellow at UCL – appeared on the BBC's Today programme on Thursday to discuss the significance of the AMS findings.

At one point in the discussion the interviewer John Humphrys asked a slightly tricky question: I understand that dark matter and dark energy are endlessly fascinating, he said, and that learning about the composition of the universe is very exciting. But what practical benefits might it bring? The answer Aderin-Pocock gave was that if we understood what dark matter and dark energy were, we might be able to use them to supply ourselves with energy – dark matter as a fuel source.

I'm sorry, but that is just rubbish.

Unfortunately, it's the kind of rubbish that is increasingly commonly voiced by scientists. You may argue that Aderin-Pocock was simply commenting on something she didn't understand – and if you  listen to the whole interview (available here for a few days; skip to the segment between 1h 23m and 1h 26m), including the cringe-worthy suggestion that dark matter and dark energy are the same thing really (because E=mc², apparently), it's hard to avoid that conclusion. But a few weeks ago I thought I heard Andrew Pontzen and Tom Whyntie suggest something similar about the Higgs boson on BBC Radio 5 (unfortunately this episode is no longer on the iPlayer so I can't check the exact words they used). And here is Jon Butterworth seeming to suggest (in the midst of an otherwise reasonable piece) that the Higgs could be used to power interstellar travel ...

Why do people feel the need to do this? It's patently rubbish, and they know better. Do we as a scientific community feel that continued public support of science is so important that we should mislead or deceive the public in order to guarantee our future access to it? Do we feel that there is no convincing honest case to be made instead? Or are we just too lazy to make the honest case, and so rely on the catchy but inaccurate soundbite instead?

I think the sensible answer to the question John Humphrys posed would go something like this. Discovering the nature dark matter is a fascinating and exciting adventure. Knowing the answer will almost certainly have no practical applications whatsoever. However, on the journey to the answer we will have to develop new technologies and equipment (made of ordinary matter!) which may serendipitously turn out to have spin-off applications that we cannot yet foresee. More importantly, the very fact that the search is fascinating is part of what draws talented and creative young minds to physics – indeed to science – in the first place, from where they go on to enrich our society in a myriad different ways, none of which may later be connected to dark matter at all. I tried to make this case at greater length here in the early days of this blog.

It's a more subtle argument than just throwing empty phrases about "energy source" around, and it might be hard to reduce to a sound-byte. But it is justifiable, and also honest. And since science is after all about careful argumentation, let's have less spin all round please.

Higgs animations

The news recently from the LHC experiments hasn't been very exciting for my colleagues on the particle theory side of things (see for instance here for summaries and discussion). But via the clever chaps at ATLAS we do have a series of very nice gif animations showing how the evidence for the existence of the Higgs changed with time, as they collected more and more data.

This example shows the development of one plot, for the Higgs-to-gamma-gamma channel:

That's pretty cool. Also nice to see the gif format being put to better use than endless animations of cats doing silly things! (Though if you are a PhD student, you might find this use of gifs amusing ... )

Here's another one, this time for the decay channel to 4 leptons:

Note that in this case the scale on the y axis is also changing with time! There's a version of this animation with a fixed axis here, and one of the gamma-gamma channel with a floating axis here.

More new physics prizes

The news today in physics, reported by the New York Times and Peter Woit, is that Yuri Milner, the Russian billionaire physics enthusiast, has announced a new set of prizes for fundamental physics. I wrote a little about the previous award of prizes here. These prizes are somewhat less generous than those announced over the summer (which were worth \$3 million each); this time only Stephen Hawking receives that amount, and the others get a smaller share. Woit typically notes that almost all the non-experimental recipients have some connection to string theory.

But the other interesting thing about the new prizes is that in this round, some experimentalists have actually been included. Of course all of them are involved with the LHC at CERN: no surprise there, given Milner's personal interests in physics.

What I do find rather noteworthy, however, is the way in which the prizes have been divided. $1 million is to be divided between the current and former ATLAS spokespersons Fabiola Gianotti and Peter Jenni, and another million between CMS current and ex-spokepersons Joe Incandela, Michel Della Negra and Tejinder Virdee. Now I'm not very knowledgeable about the organisational structure or the division of labour in these experiments, but each experiment has roughly 3000 scientists working on it and everything I had read about them in relation to speculation about a possible Nobel award suggested that there was no real way to single out the contribution of any individuals out of these thousands as being especially more worthy than any other.

It does appear that Milner has found a way to do this though: pick the spokesperson elected by the experiment. Now I wonder what the reaction to this is at ATLAS and CMS. Is this regarded as fair? Do the spokespersons really make a bigger contribution to the discovery of the Higgs? I really don't know but I'd be interested to learn what people think. I know some of the readers of this blog are part of the ATLAS and CMS collaborations — if any of you have an opinion, please do share it through the comment box!

Update: Via Shaun in the comments, there is interesting news about what the current spokespersons intend to do with their money. Also, Tommaso Dorigo gives his opinion on the matter here; I have to say my views are rather more in line with those expressed in the comment by Bernhard on that blog.

Less serious update: An anonymous friend in the ATLAS group says "I can't believe Fabiola has had her choice of font vindicated in this way."

Things to Read, 2nd December

Time for another collection of worthwhile links from elsewhere on the internet.

Science links:

• Jester at Résonaances has been producing a series of very good informative posts from the frontlines of particle physics: particularly worth reading are this summary of the state of play with the "detection" of dark matter by the Fermi telescope, this explanation on what is and isn't contained in the new Higgs analyses from the LHC, including intriguing information on why some data hasn't yet been updated, and this take on the relevance of the LHCb measurements of Bs meson decay for supersymmetry (which has been the subject of a lot of hype in the popular press).
• Speaking of the popular press, Time magazine has seen fit to nominate the Higgs boson as one of the candidates for "person of the year" (you can vote for it if you like). As if that weren't ridiculous enough, the accompanying description must surely qualify as one of the worst pieces of science journalism ever: literally every single sentence is wrong. Worth a look — even if you're not a physicist, you might be able to spot the mistakes.
• I've recently discovered a series of super-slow-motion videos of lightning strikes knocking around on the internet. These are shot at several thousand frames per second, and really show the details of how the charge leaders meander towards the ground before the main secondary stroke follows. Even more interesting are some videos showing lightning travelling upwards, from ground to cloud. Here's a video:
  
  
  and here's a popular-level description of the phenomenon.
• Another particularly cool video I saw some time ago was this one, showing the synchronisation of 32 metronomes placed on a flexible platform:
  
  

Other links:

• This one is part science, part history and part politics. Have you ever wondered what the connection is between prehistoric plankton from the Cretaceous era, and the distribution of votes for Obama? Of course you haven't, but now you can find out anyway. 
• On a more serious note: one of the striking things about the US election was how completely wrong Republicans and the right-wing were in their predictions of the outcome. Especially so since there were so many people who were able, by simple analysis of the available facts, to arrive at predictions that were much better (Nate Silver, for one). There is lots to be said about this, I suppose. One striking observation, which maybe hasn't been made enough of, is the hope that people realise that if the right-wing media can spout such rubbish (not to say lies) about the polls, perhaps the rest of what they say is rubbish too. 
• And following on from that, an interesting article from someone on the right of American politics: The Revenge of the Reality-Based Community.
• It's not just in the US that facts have a well-known anti-right-wing bias of course. And it's not just US right-wing politicians who dislike them. When economist Jonathan Portes of the National Institute for Economic and Social Research appeared before the UK parliament and explained some fairly elementary economics that happens to contradict the ideology of the Conservative Party, he received thinly veiled threats from MP Jesse Norman (watch; transcript). This drives other economists to express their equally thinly veiled contempt. Norman responds, and Wren-Lewis dismisses him again.
• And finally, something more cheery: some time ago I posted the story about the dog who climbed a mountain with me in the Himalayas. I thought that dog was pretty awesome, but then I saw this dog, who seems to have done an even harder climb!
  
  
  
  (She does seem to have a protective harness though, which probably gives her an unfair advantage ...)

Things to Read, 8th September

I have been neglecting this series over the summer, so there are rather a lot of things to highlight today.

Science items:

• The most interesting piece of physics news over the last few months has been that the wealthy Russian investor and physics fan, Yuri Milner, decided to award a 'Fundamental Physics Prize' to 9 theorists he chose himself. The amount of the award is a staggering $3 million each, wired overnight into the physicist's bank accounts — as many people have pointed out, this makes the prize worth far far more than the Nobel Prize. Suddenly being a physicist almost appears to be a lucrative career choice. The lucky physicists were Nima Arkani-Hamed, Alan Guth, Alexei Kitaev, Maxim Kontsevich, Andrei Linde, Juan Maldacena, Nathan Seiberg, Ashoke Sen and Ed Witten. All big names in theoretical physics.
• Unsurprisingly, the award of this prize generated a lot of debate. For one thing, it is a huge amount of money. For another, the prizes were awarded basically on the whim of one man, who is not a physicist himself. But perhaps the most controversial thing was reported in the New York Times:
  

  Unlike the Nobel in physics, the Fundamental Physics Prize can be awarded to scientists whose ideas have not yet been verified by experiments, which often occurs decades later.

  This was picked up on by Peter Woit, who is of course well-known for his dislike of some of the work on string theory that the said physicists are famous for, and was highly critical of the prize, including in an article for an Italian newspaper (English transcript from his blog). I guess most physicists would share his unease with the prize, if perhaps not with string theory itself. It was quite amusing to read Matt Strassler finding himself in a position of agreement with Woit but managing to attack him nevertheless (I get the feeling he really dislikes Woit).
• Motivated by this discussion, Strassler did put up a very interesting and nuanced personal defence of string theory. Whether you have an opinion on 'The String Wars' or not, you will probably have heard strong criticisms of string theory. This piece will provide some balance.
• Among the other worthwhile physics discussions were two guest posts at Cosmic Variance: by Terry Rudolph and Douglas Finkbeiner. Both discuss recent research work (in quantum mechanics and searches for dark matter, respectively) and both include interesting little insights into the world of academic publishing.
• Outside physics, I saw a piece by Dr. Dave Hone in the Guardian science section that includes the lines:

  [...] we have dinosaurs everywhere around us. We have dinosaurs nesting in trees in our gardens, tiny dinosaurs that can hover and fly backwards and feed on nectar, aquatic dinosaurs that live in Antarctica. There are dinosaurs that we eat, we have dinosaurs that can circle the globe without landing, intelligent and puzzle-solving dinosaurs, tall and flightless dinosaurs that can sprint at over 40 miles and hour, and brightly coloured and beautiful dinosaurs almost too numerous to mention.

Other items:

• Of course the big news over the summer has been the Olympics. It's been impossible to miss the outpourings of national pride in British newspapers at Team GB's medal tally and I have heard also of despondency in countries such as Russia and Australia. But what is the benefit to a nation from this arms race for medals? This was discussed, rather provocatively perhaps given the timing, by Ian Johnson in the New York Review of Books. 
• There's been a lot of discussion in the US about the Republican presidential ticket, and in the UK about the dire state of the national economy, now in a longer slump than during the Great Depression. Paul Krugman made the obvious connection, and labelled Chancellor of the Exchequer George Osborne "Britain's Paul Ryan." That post includes a graph that should be shown to everyone who still believes austerity in the recession is the answer to anything:
  
  
  
  One could forgive Krugman for feeling rather frustrated (and perhaps a little smug), because this is pretty much exactly what he predicted back in 2010:
  

  The British government’s plan is bold, say the pundits — and so it is. But it boldly goes in exactly the wrong direction.

  See also here.
• Of course some people might remember the 20 "leading economists" who wrote an open letter to The Sunday Times supporting George Osborne's fiscal plans back before the 2010 election. Well, some time ago the New Statesman had the bright idea to go back and ask them if they still stuck by their advice: 9 of the 20 had changed their minds, 10 refused to comment, and only one still agreed with himself.
• You might wonder what a poor politician is to do: if you have only a degree in History and an ideology as substitutes for genuine competence, you naturally rely on the advice of professional macroeconomists. But when the economists disagree with each other, which ones should you listen to? Jonathan Portes had a post laying out some sensible criteria for judging who to take seriously. Unsurprisingly, people like Krugman, Simon Wren-Lewis and Martin Wolf passed the test, but none of the Sunday Times economists did. Portes notes that not all those who pass his test always agree with each other — but he still always takes them seriously.
• The New York Review of Books carries a review of two books on the current global and American economic mess by Paul Krugman (End This Depression Now!) and Joseph Stiglitz (The Price of Inequality: How Today's Divided Society Endangers Our Future). What particularly interested me here was learning just how radical Stiglitz appears to be.
• Incidentally, for those who were interested in the Niall Ferguson episode featured here, John Cassidy in the New Yorker has a longer look at the arguments, and comes to the same conclusions: Ferguson is a lightweight who is being repeatedly knocked to the canvas, and this "isn't a fair fight".
• And finally, since I'd like to end on an uplifting note, here's a video to cheer us all up.

Things to Read, 28th July

Physics items:

• New results are in from the dark matter search at the XENON100 detector in Gran Sasso in Italy. See here for technical slides, or read the summaries at Quantum Diaries or Cosmic Variance. Basically, they see no dark matter events above the background expectation, so the exclusion limits on WIMP mass and cross-section are extended. As Sean Carroll points out, the results appear to be in some tension with some other experiments, but these things depend on theoretical assumptions about the nature of dark matter.
• In the Guardian, Jon Butterworth muses about the 'impact' of the discovery of the Higgs, and on the usefulness of 'impact' in general as a guide for deciding what scientific research to fund. There are some worthwhile points there, especially about who should get to decide which science has an 'impact' and which not. But I felt on some issues the piece was rather confused — he first seems to suggest that "a sense of progress" and the satisfaction of simply "adding to the body of human knowledge" are sufficient justification for funding fundamental research that may have no other forseeable benefit, but later says he disagrees with the statement that "the acquisition of knowledge is somehow morally or intellectually superior to the application or dissemination of knowledge". So which is it?
  I wrote about my own views on the justification for funding science research that has no obvious economic, medical or social payoff here. I do think it is justifiable, even if one can safely predict that there will never be any direct benefits from such research (serendipitous spin-offs, like the common examples of the internet or MRI, are a separate issue, but cannot be guaranteed). So it annoys me to see people constantly trying to justify studying the Higgs boson in terms of what hypothetical technological advances it might bring. Face it, there won't be any — if you don't believe me, here is Steven Weinberg saying much the same (among other interesting things!), or click here to see just how hard it is to come up with any remotely plausible technological speculations consistent with known physics.
  The point is that there already exist good enough reasons for funding fundamental research, so let's leave out all the rubbish about Higgs-powered spaceflight and so on, shall we?
• Readers may have already seen elsewhere the story of the physicist Paul Frampton, who has been in an Argentine jail for several months, facing charges of drug smuggling. It's a sad and frankly incredible story; I see (via Peter Woit) that Frampton expects he might be released soon (though he's been wrong about this before).

Other items:

• There is a fantastic super-slow-motion video of a lightning strike, shot at 7207 frames per second, available here, with a nice little explanation of the mechanism of the strike. I'd highly recommend it!
• A Canadian wonders whether the Euro is worth saving at all.
• Is there a magic button for the UK government to press? Do they want to press it?
• On a more cheerful note, some time ago Peter Coles posted Patrick Barrington's lovely comic poem I Had A Hippopotamus. It begins like this:

  I had a hippopotamus; I kept him in a shed
  And fed him upon vitamins and vegetable bread.
  I made him my companion on many cheery walks,
  And had his portrait done by a celebrity in chalks.
  
  His charming eccentricities were known on every side.
  The creature’s popularity was wonderfully wide.
  He frolicked with the Rector in a dozen friendly tussles,
  Who could not but remark on his hippopotamuscles.
  
  [...]

  Barrington's best known poem The Diplomatic Platypus is also great fun (and has a strangely similar theme).

Things To Read, 16th July

When I first decided to start collecting together links to interesting things on the internet and putting them into one blog post per week, I was envisaging something like a less frequent version of this. Instead these posts have become something slightly different: longer, because I like to add short comments on the articles I link to; and perhaps more selective. This meant that these posts were becoming a little too much work! I also don't always find enough physics links to highlight each week.

So I have decided to embrace the change: these posts will remain a regular feature, but no longer necessarily a weekly feature. Instead I shall put them out as and when I have collected enough items I'd like to point out and briefly comment on. The title of the series will also be amended to reflect this.

Anyway, since I have already started writing something for today, I will include a few items:

1. I was particularly interested in this little post by Julianne Dalcanton at Cosmic Variance, about the employment chances for physicists who choose to, or for whatever reason have to, leave the world of academia. The statistics — at least in the US — appear to be relatively encouraging, and somewhat better than for "lab-based" biologists or chemists. Julianne has her speculations as to why this should be so; I suppose they sound quite plausible.
   I think the other point she makes is really important too — students enrolling for physics PhD programmes really ought to be aware that the odds against them ever getting a permanent academic position equivalent to that of their advisor are very small. Say the average professor sees one student through to a PhD every two years. Over a career of 40 years, that's 20 completed PhDs, and yet when that professor retires, only one permanent faculty position becomes available. Odds like that mean that, unlike the UK government, every sensible PhD student should be aware of the need to have a Plan B. This applies also to those of us who have been lucky enough to get a foot on the ladder in the form of a post-doc job (though I don't seem to have taken my own advice yet!).
   
2. Tucked away in the Guardian, I saw this report on the treatment in Pakistan of Nobel-Prize-winning particle theorist Abdus Salam, both before and after his death in 1996.
3. Anyone who has been following the US Presidential elections will know that there has been some amount of kerfuffle recently about who was in charge of which company when. You could see this for a little perspective, or doubtless there are countless other places you could read about it. Anyway, that's not what interests me: I don't have a vote in this election, and if I did, I wouldn't need stories about Bain Capital to know that Romney is a ridiculous candidate.
   Instead, I think the significant occurrence from the last week was this quote from Barack Obama:

[I]f you’re a head of a large private equity firm or hedge fund, your job is to make money. It’s not to create jobs. It’s not even to create a successful business – it’s to make sure that you’re maximizing returns for your investor. Now that’s appropriate. That’s part of the American way. That’s part of the system. But that doesn’t necessarily make you qualified to think about the economy as a whole ...

Phew. At last some politician has come out and said something sensible. I would have thought it was fairly obvious that the analogy between running a country and running a business was completely wrong — after all, I doubt there is a company anywhere in the world that sells its product primarily to its own employees — but still most politicians continue to treat people like idiots. This is not restricted to the US: in Britain the analogy used by the Tories is different — that government budgets are like family budgets, complete with credit cards and tightening belts — but the underlying fallacy is basically the same (which family buys goods and services primarily from itself?). I don't know exactly what rhetorical devices politicians use in Germany, Spain, Greece and the like, but from the utter mess they have made of the Euro, one can surmise that they must be equally stupid. So one-and-a-half cheers for Obama for attempting to right that trend.

Found the Higgs, not the mermaids

Once again not a long post — in fact I was in the middle of typing a simple congratulatory message when I noticed that Rhys got there before me. The facts to take home from today's presentations can of course be found on many physics blogs: basically, a particle has been found, at a mass of around 125 GeV, it is a boson, so far it behaves as we would expect a Standard Model Higgs to behave (there are some small discrepancies which may or may not be indications of the deviations that all theorists would love to see). So, as Rhys says: congratulations to everyone, and we hope to learn more soon.

In the meantime though, I notice (h/t Rob) that the most popular science articles on the BBC website at the moment are the following:

We've found the Higgs, but not the mermaids.

Which suggests that although science marches on, science education still has some way to go.

What is the Higgs, and why is tomorrow's announcement important?

Although the title suggests this will be a long, detailed post full of explanations of particle physics, it actually won't. This is partly because I haven't the time or inspiration to write one, but mostly because it has been done much better elsewhere. Instead I'd like to draw your attention to a few excellent background pieces so that you can be well-prepared for what promises to be a very important press conference tomorrow (indeed Peter Woit now suggests that ATLAS and CMS will each present nearly-5-sigma evidence).

The first of these is a new post by Shaun at partner blog The Trenches of Discovery, which provides a nice layman-level overview of why discovering the Higgs would be cool, but theorists hope it isn't just the Higgs. A similar theme was discussed by Jester (Adam Falkowski) at Résonaances. He has also got a series of countdown posts, each explaining some aspect of Higgs physics, but these posts are all at a more technical level than Shaun's. At Cosmic Variance, John Conway has reprised an old Higgs overview post (from 2007) which is again aimed at the non-expert. There are other pieces I won't link to now, because these cover most of the bases for anyone interested.

LftW: 2nd July

Physics links:

• The important physics event of the next week will be the CERN press conference on the Higgs search analyses coming up on Wednesday at 9 am CEST. Peter Woit provides a preview, summarising what we might expect to hear. At Quantum Diaries, Aidan Randle-Conde explains why we might not want to combine the significances of detection obtained from ATLAS and CMS in order to obtain the magical "5 sigma" standard for detection. The official results probably won't provide a combined significance for this reason, but doubtless various bloggers and others will do so.
• On the day itself, this blog will not be the best place to get your news. Instead, you might wish to go here, or to one of the other links down the right-hand panel.
• On Friday, there was an intriguing paper uploaded to the arXiv, proposing a new type of dark matter detector made out of gold foils and single-stranded DNA. I don't know what to make of this paper: it sounds a little crazy, but then I don't know much about the molecular biology of using ssDNA. Two of the physicist authors — Katherine Freese and David Spergel — are well-known, serious scientists. I presume the other authors are biologists.
• Peter Coles put up a nice set of "order-of-magnitude" physics problems to have a go at, including for instance "How much brighter is sunlight than moonlight?"

Other links:

• David Bromwich is very disappointed with Obama.
• On the other hand, Obama won a victory in the US Supreme Court last week on his healthcare reforms. Who benefits? Ask Paul Krugman.
• Other big news this week was that Germany finally conceded a little ground to Spain and Italy in Eurozone rescue talks. How significant was this? Some opinions here, here, and — interestingly, just before the concession occurred — here.
• Martin Wolf: What was Spain supposed to have done? (See also here.)
• Mark Thoma: Laughing at the Laffer Curve (and follow-up)
• A Manifesto for Economic Sense (that's behind a paywall, so you can read it here instead)
• 'Science' Without Falsification: Noah Smith and others
• This response to a New York Times op-ed piece is one of the funniest things I read all week. I think Americans might call it a "smack-down".
• And finally, something I missed out last week: for Paul McCartney's 70^th birthday on the 18^th of June, the Guardian ran a nice interactive feature with original reports from important moments in his life. I thought the most interesting one was this report from 1969, with a story of how fans from the US kept ringing a "magic telephone number" in England in order to speak to Mr. Billy Shears ...

Victor Keegan's Guardian report on mysterious phone calls from the US ... 

LftW: 25th June

Sorry about the relative lack of posting, this will be rectified soon. Here are some of the things I noticed last week.

Physics links:

• As you will no doubt already have heard from elsewhere, there is a press conference scheduled at CERN for the 4th of July, in which updates on the status of the searches for the Higgs boson at the ATLAS and CMS detectors will be provided. You've probably also heard the rumours that the results will feature higher statistical significance than the previous results from last December, and possibly even an official announcement of "discovery".
  
  I believe these rumours originated from Peter Woit's blog (see here and here), and they have caused a bit of a kerfuffle in the blogosphere. Matt Strassler rather bad-temperedly complained about "non-particle-physicist bloggers" spreading rumours, and Jon Butterworth also seemed a little upset, claiming spoilers would be "bad for science". Personally, I don't see how that argument works. Sure, I understand any scientist only wants to make an official statement in a professional capacity when they're sure they've got the analysis correct. And a large collaboration has to have rules to govern behaviour of individuals, so they're well within their rights to want to avoid leaks. But I don't see how, if the leak is made, publishing a blog post clearly marked as "rumours" is bad for science. If anything, it simply ensures that more people tune in to the press conference to check whether the rumours are actually true. (I suppose this makes it slightly more likely that the servers providing live streams from CERN will fail.)

• Still on the topic of the Higgs, Matt Strassler also got rather annoyed with a New York Times article on the topic: here and followed up here. Again, it's not something that bothered me too much, but at least in this case I do recognise the feeling of seeing some arcane aspect of your field slightly misrepresented in a summary in the popular press and getting worked up about it. (If the rumours above turn out to be true then this principled objection will be even less relevant!)

• On a completely different note, here is an amusing little game that incorporates special relativity (hat tip to Shaun). 

Other links:

• In the UK, the Education Secretary Michael Gove apparently wants to do away with GCSE qualifications for 14-16 year-old students and go back to the old O-level exams. I don't have any sensible comments to make about the advisability or otherwise of such a plan, but I did see Peter Coles had posted a link to a GCSE Science paper from 2006. It is absolutely astonishing. Question 3 is a particular classic.

• Two weeks ago Jonathan Portes caught George Osborne implicitly admitting his economic policy had been wrong for the last two years. Last week he caught the G20 admitting they'd been wrong too.

• I recently learned about the confluence of the Rio Negro and the Solimões river (which later becomes the Amazon) in Brazil, where the waters of the two rivers, which are very different colours, flow side-by-side for nearly 6 kilometres without mixing (because they are at different temperatures, and flow at different speeds). This makes for nice dramatic photographs, and I couldn't resist including one here:

Confluence of Rio Negro and the Solimoes.

Interregnum

I'm going on holiday for a week, and will be avoiding the internet as much as possible. So no new blog postings until I'm back. Instead I'll leave you with a fun CERN video from 1967, pointed out to me in the comments on this post by my friend Rob. As he noted, the bit around 9 minutes in when the scientists attempt to explain on a blackboard what they are trying to do at CERN is quite funny!

Links for the week - dark matter special

A longer blog posting should ready by the weekend, but is proving a little harder to write than I had hoped. In the meantime, here is a collection of interesting things to read elsewhere. I will make this sort of a roundup of worthwhile links a weekly feature on this blog, though it will make more sense to put it out at the weekend next time. Anyway, here you go:

Physics links:

• Dark matter detection experiments have been in the news a lot recently. A couple of pre-prints have claimed to have seen some tentative evidence for a dark matter annihilation signal in gamma-ray data from the Large Area Telescope on the Fermi satellite, that somehow wasn't seen by the Fermi guys themselves. Matt Strassler discusses the first of these papers here. Rhys provides a nice short summary of both; you may also want to read a more bombastic discussion on Lubos Motl's blog.
• The Cryogenic Dark Matter Search (CDMS) detection experiment earlier this year found no evidence for an annual modulation of dark matter interaction events in its detector, apparently contradicting earlier experiments DAMA and COGENT. A new pre-print from two members of COGENT claims CDMS mis-analysed their own data and there isn't a contradiction. (I'm not sure what to make of this: the argument seems pretty straightforward but I'm no expert so I might be missing some elementary things. Comments welcome!)
• To make the story murkier still, this paper accepted by the Astrophysical Journal claims to find no evidence for dark matter in the solar neighbourhood based on the dynamics of stars in our galaxy, which would presumably rule out the possibility of direct detection. There are a number of caveats, so caution is advised: see here and Matt Strassler's post above. But then this paper, accompanied by this press release, makes an even more inflammatory claim about the non-existence of dark matter. Peter Coles provides a sceptical review (and entertaining arguments in the comments section!).
• In case you are now thoroughly confused by the status of evidence for dark matter, Sean Carroll at Cosmic Variance gives us the transcript of a debate that sums up the main cosmological issues.

Phew, what a lot of dark matter. I realise some of the links above are not very recent — this blog is new and has some catching up to do! Now for other stuff.

Other links:

• In the Guardian, Barney Ronay has a brilliant piece recalling an inspiring Olympic moment: Michael Johnson breaking the 200 m world record at Atlanta '96. If, like me, you watched the race at the time, you will have it forever seared in your memory. If not, here's a video:

• Jonathan Portes uses charts and figures to illustrate why the UK government's economic policy is the opposite of sensible. See also here.
• Paul Krugman gets zapped by evil aliens.
• Peter Woit reviews a philosophical book on physics, and gives it a thumbs up. 
• Gary Wills on The Myth of Marriage.
• Private Eye lists some of the things Rupert Murdoch might have forgotten during his testimony to the Leveson inquiry.

Steven Weinberg: The Crisis of Big Science

A few weeks ago, via Peter Woit's excellent blog, I was alerted to a recent article in The New York Review of Books by Steven Weinberg, titled The Crisis of Big Science. Woit added his own thoughts on the article, and there are many interesting opinions expressed in the comments section there. However, I felt that a very important question was not satisfactorily answered, as I will try to discuss here.

Weinberg provides a brief and personal overview of the development of particle physics experiments, starting from Rutherford's pioneering gold foil experiment in 1911 (the "experimental team consisted of one postdoc and one undergraduate [...] supported by a grant of just £70 from the Royal Society of London"), through the invention of cyclotrons, the postwar development of accelerators and the construction of dedicated accelerator facilities at Fermilab and CERN, to the current multi-billion dollar Large Hadron Collider (LHC) which (we hope) will confirm a detection of the Higgs boson later this year, and might yet — if we are lucky — provide exciting clues about the correct particle physics theory at higher energy scales than we have yet probed.

One of the obvious themes in this short history is the enormous and growing cost of building the experimental facilities required to increase our knowledge about particle physics. Obtaining the money for these facilities is always difficult, and sometimes impossible. Weinberg reflects in particular on the cancellation in the 1990s of the Superconducting Super Collider (SSC):

Then in 1992 the House of Representatives canceled funding for the SSC. Funding was restored by a House–Senate conference committee, but the next year the same happened again, and this time the House would not go along with the recommendation of the conference committee. After the expenditure of almost two billion dollars and thousands of man-years, the SSC was dead.  

One thing that killed the SSC was an undeserved reputation for over-spending. There was even nonsense in the press about spending on potted plants for the corridors of the administration building. Projected costs did increase, but the main reason was that, year by year, Congress never supplied sufficient funds to keep to the planned rate of spending. This stretched out the time and hence the cost to complete the project. Even so, the SSC met all technical challenges, and could have been completed for about what has been spent on the LHC, and completed a decade earlier.

(The claim that projected costs only increased because of insufficient spending every year is interesting, and something I hadn't heard before. I don't know whether it is true, but it sounds plausible.)

This is not simply a problem for particle physics. The same pattern holds — though at a somewhat lower cost level — for my own field of astrophysics and cosmology. Recently, the US Congress decided to scrap funding for NASA's James Webb Space Telescope and the US has also decided to terminate the IXO (X-ray) and LISA (gravitational waves) projects, which caused the European Space Agency to choose to fund a mission to explore Jupiter's moons (known as JUICE) over projects that would have been more relevant to cosmology.

In the end, the point is that the political support for a such massive science experiments is hard to obtain. Weinberg says

During the debate over the SSC, I was on the Larry King radio show with a congressman who opposed  it. He said that he wasn't against spending on science, but that we had to set priorities. I explained that the SSC  was going to help us learn the laws of nature, and I asked if that didn't deserve a high priority. I remember every word of his answer. It was "No."

Now this is the question I'd like to focus on. Let's leave aside for now the question of whether a convincing science case can in fact be made for an SSC-like accelerator or JWST-like space mission (Peter Woit's post discusses this for a new particle accelerator); I will assume that the proposed experiment, whatever it may be, will indeed help us "learn the laws of Nature." Is this justification enough for vast government funding?