Ted Bunn’s Blog

Governor Schwarzenegger sent a letter to the California assembly along with his veto of a recent bill.  The first letters of each line of the message spell out a certain vulgar phrase.  The Governor’s office says it’s a coincidence, but apparently lots of people don’t believe them.

This has a lot in common with the subject of a colloquium I gave here at the Université Paris last week.  (If you really want to, you can see the slides for this talk.)  My talk was about several unexpected patterns that have been observed in maps of the microwave background: there are a number of things that should, according to the standard theory, be random but that look non-random.  There’s a lot of controversy over whether these patterns are significant.  The problem is that after you’ve noticed a pattern, it’s very hard to quantify just how unlikely that pattern is, and hence whether it demands an explanation.

Human beings are really good at pattern-finding.  Maybe what we’re seeing is a chance fluctuation, and we’re just fooling ourselves into thinking it’s a pattern with an underlying cause.

The probability of this particular phrase being spelled out in this particular way in Schwarzenegger’s letter are something like one in a trillion.  But if you want to decide whether you think an explanation is required (i.e., that someone did it on purpose), that one-in-a-trillion number isn’t the right one to use: you should  try to figure the probability of something like this happening, rather than the probability of this particular thing happening.

Suppose that you read in the paper that Mary Jones won the lottery.  You’re not likely to be astonished by that fact, even though the probability of this particular person winning the lottery is very small. The reason is simple: the probability of someone winning the lottery is quite large.

So in the cases of both the microwave background and the vulgar acrostic, we should ask how unlikely is it that some similarly unusual pattern would show up.  The problem is that it’s very hard to phrase that question precisely enough that it has a meaningful answer.

So what should we do?  In Schwarzenegger’s case, we should get whatever juvenile amusement we can out of the situation, then decide that it just doesn’t matter and move on.  In the case of the microwave background, things are a bit different: if these patterns are real, then they may be telling us something scientifically very important.  So we should try to figure out new data sets that will shed light on the question.  Unfortunately, that’s hard to do.

Ken Ganga, a member of the Planck satellite collaboration, has some nice pictures of the launch on his blog.  (Not exactly breaking news, but I just found out about these pictures.)  There’s also a story about a potentially fatal problem with the satellite that was caught just barely before launch.

By the way, in addition to his Planck blog, Ken has a personal blog, mostly about funny things he’s found while living as an American expatriate in Paris.

My colleague Jerry Gilfoyle and I were just awarded an NSF grant to buy a new computing cluster.  In the past, my students and I have mostly worked on problems that could be attacked with ordinary desktop computers.  This grant means that we’ll be able to go after more computationally intensive problems.  It also means I’ll have to learn about supercomputing techniques.  Fortunately, Jerry’s very experienced at this.

This has been a good funding year for me: I submitted three NSF proposals, and all three were funded. That’s at least partly due to the federal stimulus bill: only one of the three is officially stimulus money, but no doubt all the stimulus money washing around freed up more non-stimulus money for other grants.

Correction: Actually, two out of the three, including the computing cluster, are stimulus funds.  I’m nothing if not shovel-ready.

 Our local public radio station aired a short interview with me about an NSF grant I was awarded recently.

I don’t know whether the interviewer is aware of what I wrote about a previous piece he did; I hope not.  Needless to say, I like the piece about me better.

Successful launch yesterday.

Like most academics, I obsessively keep track of who’s citing my work.  As a result, this paper caught my eye today.  (If that link doesn’t work, try this one.)  The lead author is a UR alumnus and winner of both of the physics departments main awards in his senior year.  During my first year here, I taught him in an independent study course on relativity.  He went off to graduate school in mathematics, but he later saw the light and came back to physics.

I haven’t read the paper in detail yet, but from the abstract it looks like a very nice piece of work (in addition to having the good taste to cite me). Congratulations, Andrew!

My paper with Hogg on the interpretation of the cosmological redshift has been officially accepted by the American Journal of Physics.  Here’s the final version.  It’s changed in a bunch of small ways from the previous versions, but the basic argument is still the same.

Two papers I submitted a while ago were accepted for publication by the American Journal of Physics this week, within minutes of each other as a matter of fact.  To be precise, they were “conditionally accepted,” meaning that they’ve successfully passed the review by external referees and the science content been deemed acceptable.  There’s a further review by the editors for style, clarity, etc., before they’re  finally accepted.  Because AJP is a journal with a pedagogical slant, they place a heavy emphasis on clarity, which is probably why they have this “conditional acceptance” stage.

Both of these are less technical than the usual research paper: they’re intended for readers who know some physics but are not necessarily specialists in any particular field.  The first one requires a bit of knowledge of relativity (students who took my Physics 479 course should be fine) , and the second one requires just undergraduate-level thermodynamics and statistical mechanics.

The first article is on the correct interpretation to place on the observed redshifts of galaxies in the expanding Universe.  I blogged about it when we originally submitted it.  These redshifts are usually described as being due to the “stretching of space,” but David Hogg and I argue that this conceptual model is misleading.  We claim that, contrary to what you often see in introductory textbooks,  it’s correct to think of the redshift as being due to a plain old Doppler shift.

Here’s the revised version of the paper.  It  doesn’t differ all that much from the one we originally submitted, although some aspects of the argument are expanded and clarified a bit in response to the referees’ comments.

The second article is on the relationship between entropy and the second law of thermodynamics.  It’s a response to a very nice paper by Daniel Styer, which attempts to show quantitatively that the entropy production due to sunlight is more than enough to account for the entropy reduction required for biological evolution (contrary to claims often made by creationists).  The original article had a serious gap in it: it depended on an assumption that was unjustified and, I argue, almost certainly wrong.  My paper presents an argument that doesn’t depend on that assumption.  The new argument shows quite rigorously that there is no conflict between evolution and the second law.

I blogged about the original Styer article and about my response a while back.  Here’s the revised version of the paper.  Thanks to the referees, I think the new version is much clearer than the original.  It’s also much longer.  I was thinking of the original as just a comment on Styer’s earlier paper, but the new version reads more like a stand-alone article.

The Planck Surveyor, the European Space Agency’s satellite-borne microwave background telescope, is preparing for launch on April 16.  Andrew Jaffe has some pictures of the preparations.

Planck will map the microwave background with finer resolution than NASA’s WMAP satellite.  It’ll also cover a considerably broader range of frequencies.  This is helpful in separating the microwave background from other, more local sources of radiation.

I think I’m still officially a member of the Planck team in some sense, although I haven’t done any real work on it.

The paper that I coauthored with Brent Follin (UR undergraduate) and Peter Hyland (Wisconsin grad student turned McGill postdoc) has officially been accepted for publication in Monthly Notices of the Royal Astronomical Society.  I thought it would be, but it’s still nice to make it official.  Congratulations to Brent especially, for becoming a published scientist.

Unlike the last one I posted about, this is a “real” refereed paper.  We decided to submit it to Monthly Notices, not Astronomy and Astrophysics as I wrote in my earlier post, for reasons that aren’t at all interesting.  Monthly Notices is a very good journal, and it has a way cooler name than A&A.