a geocentric view

It's Official

2009-03-14T12:45:00.000-04:00

Assumptions: Quote of the Day

2009-03-07T02:57:00.001-05:00

Godel says you have to assume shit; physicists just give an explanation for why it is brown and smelly.

Snow Days are for Lazy Wusses

2009-01-28T12:23:00.001-05:00

President Obama would like for you to all grow up and deal with it. "It" in this case is the weather. Quit being lazy, suck it up, clear your roads and get to work.

... Obama said he wanted to make an unrelated comment to the press. In a slightly amused tone, he noted this his daughters' school, Sidwell Friends, was canceled today because of a snow and ice storm that hit Washington.

The suburban schools systems and many private schools in the region were closed today and the District public schools opted for a delayed opening because of the sleet and freezing rain that made some roads and many sidewalks treacherous.

"Because of what? Because of some ice?" Obama said to laughter around the table. ...

He concluded by saying: " ... I'm saying that when it comes to the weather, folks in Washington don't seem to be able to handle things."

In the meantime, half of the graduate students in my department were here this morning for Coffee. We even talked about science for forty minutes, in a way that didn't resemble Lord of the Flies at all. No one else has shown up yet.

Books about Kitties: Dewey and Cheezburgers

2008-12-08T13:00:00.002-05:00

The Winter Solstice is quickly approaching, so I know you're looking for gifts for the special people in your life. Lots of people like both kitties and books, so here are two book reviews of recently read kitty-themed books.

Dewey: The Small-Town Library Cat Who Touched the World by Vicki Myron:

On a cold winter night in 1988, someone dumped a small kitten into the book slot at the library in Spencer, Iowa. Naturally, the cat was dubbed "Dewey" and subsequently adopted by the library. Dewey: The Small-Town Library Cat Who Touched the World, while nominally the story of this apparently adorable cat, also tells the story of the librarian, Vicki Myron, who was Dewey's principal steward for the next 18 years. OK, I confess, I got this book nearly two months ago, from the publisher for free in exchange for reviewing it, no less. I had it read less than two weeks after finishing it, but I just couldn't review it. I was already having a fairly difficult month (why do you think I haven't been blogging like I used to?), and then here comes this book that I think is going to be chock full of adorable stories about a cute kitty being cute in a library. So I read it. And, sure enough, there are lots of funny stories about Dewey being a kitty, but there is also a lot about what corn-growing Iowa was like in the 1980s and 90s ... and about the ordinary yet difficult life of Myron herself, and how like many pets since humans have started having pets, Dewey somehow made everything a little bit better. The writing is straightforward and unpretentious—it's really just a librarian talking about her cat—but as the book is a quick read (and enjoyable, once you've located your box of tissues), it's sure to be a good gift for anyone who likes stories about cats or libraries.

For something more upbeat, here's a review of I Can Has Cheezburger?: A LOLcat Colleckshun with more words in the review than in the entire book, by probably an order of magnitude:

It's great having a hardcopy of lolcats (years from now this will still be a conversation starter, whether it lives in a bathroom or on a coffee table), and I was majorly looking forward to receiving my solid dose of happiness-in-book-form in the mail. As expected, it is pretty entertaining, but as other reviewers have noted, it seems that somehow the funniest lolcats were not selected for the book. (Of course, there's no selection which would not engender this kind of response from some group of people, but even though I'm one of Those People who check icanhascheezburger.com several times a day [I bought the book, this shouldn't be surprising, OK?], there were several picture/caption combinations in here that made me just go, "wtf? I don't get it. At all.") The bigger complaint that I have with the book, however, is the presentation: it could do with being a tad bigger, and having some space around the pictures. As is, it is sometimes difficult to tell immediately whether or not the two facing pages are one big lolcat or two completely unrelated ones, and the result is a bit of information overload (and not in a good way, unfortunately). There are several pages on which the presentation is really well done; some space around the picture, a cute little (unrelated) drawing. A few pages are "instruction manuals" or "classroom styles," teaching cats what such terms as "invisible" and "in ur" mean. (Though, again, these pages suffer from the page-size issue.) It's nice to see, in these cases, a presentation which isn't merely "paste picture from int0rnet into book."

Regardless of all these complaints, this LOLcat Collekshun is still a book of lolcats, and any fan of the meme will be happy to get a copy for Christmas or a birthday or a "just cuz." Srsly.

Book Review: Autism's False Prophets by Paul Offit

2008-10-01T09:35:00.004-04:00

I recently received and read Autism's False Prophets: Bad Science, Risky Medicine, and The Search for a Cure by Paul Offit through the ScienceBlogs Book Club. Offit first details the history of various attempts at defining the cause of and curing autism, focusing the most on first the MMR vaccine and then thiomersol (which contains mercury), which is contained in many vaccines (though not MMR).

In general I found this book interesting and educational (all I knew going in was that the "vaccines cause autism" nonsense was both quackery and dangerous), and I recommend it to anyone interested in the so-called controversy—there is no controversy as far as the science is concerned—as well as for the book's interesting discussion on the interaction between science and the public via the media. People distrust science and its authority figures all the time; usually this just leads to ignorance, but in the case of "let's not vaccinate our kids" it can lead to death. Which isn't cool.

Summary: Autism's False Prophets begins by offering a pre-vaccine history of autism and attempts to cure it. A pattern is established: people come up with some desperate theory, put a lot of time and effort and money in trying to "cure" their children, some of the "cures" wind up doing severe damage, parents move to next theory. Then enters the vaccine theory, which is actually two-fold. It begins in England with Andrew Wakefield announcing that the Measles, Mumps, and Rubella (MMR) vaccine increases rates of autism; he's even got an (unsupported) idea as to why this should be the case. (People seemed to not mind that he's had it out against MMR since the 1980s.) Meanwhile, as the MMR-autism link isn't able to be reproduced in independent studies and Wakefield is exposed as a fraud, a panel in the US realizes that the amount of ethylmercury in vaccines (used as a preservative, which makes the vaccine both cheaper and safer to use) is higher than the amount of recommend safe-levels of methylmercury. Spurred on by parents who have decided that their kids got autism after getting their vaccines (most austism symptoms become the most apparent about a year or so of age, right around when kids get many of their vaccines, so the emotional causal link isn't unsurprising), the panel figures that there isn't any harm in being cautious. So they announce that while there isn't any reason to be afraid, they will be looking into the situation. And all hell breaks loose.

Offit traces this aftermath right up to the Omnibus Autism Proceedings, a huge court case of thousands of parents claiming that vaccines caused autism in their children; the court's decision is due out early 2009. Offit then discusses how this controversy is a classic example of fear, scandal, and headlines driving the media narrative more than responsibly informing the public of the facts: the scientific case showing no linkage between vaccines and autism has actually been established for some years now. But, Offit argues, the public equates going online and reading what shows up on a Google search with scientific literacy, and our culture likes to buck authority, and so the result is kids dying of measles. The book closes with a short look into what actually does cause autism (it's genetic), and how a few parents of autistic children who know vaccines weren't the cause—and who don't like having their children referred to as "mad," "damaged," or "soulless"—have been responding to this whole fiasco.

Review: In general, I liked this book and found it easy to read. However, there were several stylistic points which were downright annoying. (I get the impression that while the author did his job, the editor did not.) First, there are several simultaneous storylines weaved throughout the text, yet as the story is not always told chronologically, it's difficult to keep any of the dates and the relative orderings of different "plots" straight. In this same vein, the book is written with the understanding that vaccines do not cause autism, but often the story is told like it is a story, a thriller: the case against vaccines-cause-autism isn't made strongly and irrevocably until well into the book, so someone could easily read halfway and think "zomg! conspiracy!!!" Also, as this is a book talking about how important believing the scientific consensus is, I would have appreciated it if the end notes listed at the back of the book were actually marked in the text itself. The organization of the book is also somewhat shaky, causing some interesting points get a bit buried in the text. For example: if vaccines-cause-autism really is this big conspiracy, then how come the scientists, etc. supposedly perpetuating this conspiracy vaccinate their own kids? Or that kids absorb more methylmercury from breast milk and baby formula than from vaccines in their first few months of life anyhow, a fact which is just mentioned in an off-hand kind of way in the middle of some chapter.

The two chapters towards the end of the book on science and the media and how the general public portrays science were both interesting and elucidating. I can't come up with solutions to these problems, but Offit at least lays out the issues well.

More Outliers from the Mass–Metallicity Relation

2008-09-15T11:38:00.005-04:00

Last week, my second paper on outliers from the mass–metallicity relation showed up on astro-ph. In the first one, which I described here, was on the low-mass high-metallicity outliers from the relation; I described in that first post more about what this so-called "mass–metallicity relation" thing actually is. We concluded in that paper that those galaxies must be running out of star-forming gas, and thus nearing the end of their star formation.

In Paper II, we are looking at the other corner of the mass–metallicity plane: massive low-metallicity galaxies. (Yes, it is easy to get tongue-tied in this game.) Most of the 42 galaxies in our sample look like this:They are very blue and what we astronomers called "disturbed." That's fancy-talk for "they've been playing rough with their neighbors and so their gas and stars have been all moved around so they look morphologically... disturbed." The key here is that simulations have shown that as galaxies interact, gas from really large scales will typically get drained into the centers of the galaxies. As it turns out, this large-scale gas will generically have a much lower metallicity than the gas originally at the galaxy center, so the large-scale gas inflow will effectively dilute the central gas. Relative to the amount of time we can expect for the star-formation to continue, it won't take very long for this new gas to get re-enriched by metals formed during the star formation itself, so we can expect for these luminous low-metallicity galaxies to be relatively rare.

Book Review: Halima Bashir's Tears of the Desert

2008-09-08T20:06:00.002-04:00

Over the weekend I read Tears of the Desert: A Memoir of Survival in Darfur by Halima Bashir.

Tears of the Desert details the life of Halima Bashir, a doctor who grew up in Darfur and now lives in the UK. Her story is told in a straightforward manner: how she grew up and how her family and village were important to her, how she went to school and enjoyed it and eventually went on the medical school, how war crept into her life until it became un-ignorable and eventually destroyed her life, her home, her family, and how she finally escaped from Sudan and managed to put together a new life in England. It most places—even the childhood stories—the story is riveting (which, unfortunately, also means that some of the explicit statements of foreboding come across and cheesy and unecessary). The storytelling is also often unexpectedly hilarious; I found myself laughing out loud quite a few times.

As a personal accounting of the history of the Darfur conflict, Tears of the Desert is a powerful story of how innocent lives are completely torn asunder. Bashir has lived through things that most of her readers cannot possibly imagine (yet, of course, as the book is written in the first person, we the readers know that, she at least, has survived). Her story thrusts raw emotion into the too easily glossed-over refugee and death statistics streaming out of the region. However, I found the book almost too insular at times; for example, the only year explicitly stated (aside from in the short epilogue), is the date of Bashir's birth: 1979. I was constantly adding and subtracting to determine approximate dates, and so as an actual history Tears of the Desert unfortunately falls a little short and does not serve well as an introduction to the Darfur crisis, and I fear that in ten to twenty years this fact will make it an even more difficult read. Likewise, no map is offered and only a brief description as to the underlying cause of the conflict and why the UN is doing little to stop it is given in the epilogue.

Regardless, a reader who first spends half an hour reading about the Darfur situation online should have plenty of context in which to set this book, and Tears of the Desert provides a far more personal and accessible accounting than anything the internet (or most anywhere else) has to provide.

Tears of the Desert will be on sale in the US on September 9, 2008.

Book Review: Coming of Age in the Milky Way by Timothy Ferris

2008-09-07T19:40:00.000-04:00

(Two posts in less than a week. I know. Don't get too excited.)

I recently finished reading Timothy Ferris's Coming of Age in the Milky Way. I admit: it was on a recommendation list somewhere and I was intrigued by the title, so when I saw it at a local used bookstore, I snagged it. I have not been disappointed.

Summary: Coming of Age in the Milky Way tells the story of how humankind came to know its place in the universe. Though the book has three distinct themes (Space, Time, and Creation), the main focus is on Space: how did we learn the size of the Earth, the extent of and laws governing the Solar System, that the Milky Way is a "galaxy" and only one of many, and that the universe is giant and expanding? The other two sections expand on this history of revelations. The Time section discusses how we discovered that the Earth (as well as humans as a species and the universe as a whole) are not unchanging, static and infinite, and the Creation section focuses more on the marriage of quantum physics and cosmology: how did the elements and subatomic particles and, indeed, the universe itself come to be?

Review: As an astronomer, none of the actual science here was new to me, but I can say that, unlike many popular treatments of physics, very little of the descriptions made my inner "but that's not really true ..." voice cringe. (There were maybe two pages like this, and one of them may have actually involved something that was believed to be true in the late 1980s.)

Primarily, though, this is a history book, and I found the history fascinating. Ferris paints a detailed and colorful portait of the personalities and worldly changes (politics, well-timed supernovae, etc.) that led to these revelations (and occasional setbacks). The writing is lyrical, poetic even, and yet detailed and straightforward when need be. The book is stock full of quotes, none of which feel out of place or difficult to read (as thousand-year-old quotations are apt to be). The transition of this writing style into the modern age—when quotes were garnered via interviews instead of meticulous combing of however-the-hell people figure these things out—was seemless. Though published in 1988, Coming of Age in the Milky Way is surprisingly not out-of-date 20 years later; as the views of the 1980s are not treated as The Answer, a 21st century reader will only notice that the story seems to stop a little earlier than expected.

I thoroughly enjoyed this book, and I recommend it to anyone interested in the history of science, the process of science, or general astronomy or physics.

Citations and Paper Length

2008-09-05T09:25:00.000-04:00

Interesting paper on astro-ph this morning from Kris Stanek. As it turns out, in general, longer papers tend to get cited more. The exception is that, in astronomy, two of the major journals have a "Letters" section, which limits papers to 4 pages. These Letters do tend to be cited more than other short papers (presumably because they are Really just longer papers squeezed into a shorter format). Thus the graph of number of citations versus page length looks an awful lot like the state of Ohio:
The paper also includes some silliness-tinged career advice.

In Which I Disucss What I Have Been Doing Instead Of Blogging

2008-07-11T22:20:00.000-04:00

The astute reader has pointed out that I have not exactly been "updating" this blog lately, which is to say, I haven't posted anything in basically two months or more.

Thing is, I haven't really had much to say. I spent a week at the beach (oh, such a perfect beach it was) in June with my family and the significant other. There was sand and ocean and sky and rum and sleep and shrimp boil and sunshine everything was good. I've been reading a lot. In the last two months or so, I've re-read the entire Kushiel series (except for the middle part of Kushiel's Scion since that one isn't really all that good anyhow) in preparation for Kushiel's Mercy, which I got from the library and quickly devoured. This week I read Angelina Jolie's Notes From My Travels, which is essentially a publication of the journal she kept when beginning her work with refugees and the United Nations. (I'm particularly interested in Cambodia, and so her impressions of regions she traveled through some 4 years before me were particularly interesting, though the timing of her trip to Pakistan to see and meet Afghan refugees there in August 2001 is perhaps the trip with the most interesting timing.) I'm about halfway through Obama's Audacity of Hope; having read Al Gore's The Assault on Reason in February (which was actually the inspiration for this post, though I did at the time fully intend for a book review to be forthcoming...), I have decided to try to read more, you know, non-fiction. So far the Audacity of Hope is making me realize why so many people seem to be "in love" with Obama—he uses the word "damask" in the second paragraph of chapter 1 ... how can you not love that?! So far the book seems straightforward and honest, but then, I'm pissed off about his FISA vote and the lame-ass excuses he gave over it. I'll still be voting for him, of course—in the last eight years, McCain has gone from interesting to downright frightening—but it is good to stay informed and realistic. I also started reading Daily Kos—a totally unbiased source of information, I know, but what is? and I like the snark—which has managed to make my morning coffee-and-blogs time erm slightly longer. I also finally finished Freakonomics and The Know-It-All in May ... and I've become totally addictd to LibraryThing and its vast cataloguing and statistics-generating power. While visiting my parents, I also helped them scan in a few hundred of their books; why are such things so immensely interesting?!

Oh, yeah, and I guess I've kind of been working. The first few weeks after the beach were rough (there was a dearth of ocean, rum, and soft breezes in my office, and I'd gotten used to the 10 or more hours of sleep a night), but I had a paper accepted for publication around the end of June. I had gotten around a dozen emails about it after it first showed up on astro-ph—many of which were not just asking me to cite some obscure paper of theirs! So I think this is a case where the paper—and the interpretations—did substantially improve between revisions. So now I'm working on the "sequel" paper: paper #1 was on low-mass high-metallicity outliers from the mass–metallicity relation, so paper #2 is going to be on the high-mass low-metallicity outliers. I convinced myself today that the metallicities I'm measuring for this new sample aren't bogus, so now it's time to start compiling all of the data and building an explanation for why these galaxies are the way they are. The current plan is to present the main results at a conference in August so that some of the helpful back-and-forth that happened after the last paper showed up on astro-ph can perhaps happen before the paper is submitted this time.

I've been working on several other things as well, but getting into all of that would mean *gasp* explaining in part what my so-called "thesis" is about, and we wouldn't want to rush back into this relationship too quickly, now would we? Besides, I have a book to go read.

Solving the World's Problems, One Plot at a Time

2008-05-30T14:45:00.001-04:00

Whereby "the world," I really just mean mine. Some time ago, I stated that the worst part about being a graduate student (in the astronomy department!) at Ohio State is that our offices get stupidly ridiculously hot for several weeks each year. Apparently our department chair, however, finally got the message across to The Powers That Be that 85° offices are not conducive to productivity, and this year we were spared the fortnight-long saunas.

Well, at least the temperatures were fine during the days, but come weekends, or heaven forbid, after dinnertime, the office temperatures would once again climb. The department secretary, who of course is only in the building during "standard" office hours, tried to assure us that this was because "if the AC breaks over the weekend there isn't anyone around to fix it." Then how come, we wondered, every Monday morning at 9am the AC was so quickly "fixed"? One of my officemates was convinced that the patterns we were observing were due to the AC being simply turned off outside of business hours. So, we started recording the date, time, temperature set, and temperature recorded (by the presumably reliable thermostat):

That little peak on the right there corresponds to Memorial Day weekend. On Monday I was clever enough to leave before the office reached 90 (the thermometer on the thermostat, by the way, maxes out at 85°; someone in another office had a real thermometer and mentioned such numbers the following day). Tuesday morning, the temperature decreased dramatically. We sent this nice little plot to the department chair, who then forwarded on to The Powers That Be, who, we found out this morning, used it to unravel the great "mystery": the air conditioning in this building was being automatically turned off at 5pm and turned back on at 8am—and left off for the entirety of any given weekend. We have been assured that this miscalculation of when astronomers work has been remedied.

Movie Review: Indiana Jones and the Kingdom of the Crystal Skull

2008-05-18T17:40:00.002-04:00

So this afternoon, the significant other and I decided we needed to see a movie. I voted Indiana Jones and the Kingdom of the Crystal Skull. I was told this is not actually out in theaters yet (I don't really follow these things, but I finally saw a trailer for it for the first time last night, which made me want to go see it immediately). So we settled on a 1:50pm showing of Prince Caspian. We get to the theater and pay for our tickets, but my credit card got double charged. So I had to wait at the little desk for a bit to get my card reimbursed. As this is happening, a group of people (carrying legal pads!) comes in, looking mildly confused, and the lady helping me asks, "Indiana Jones?" My head does several 180s; she explains it's a press showing. "I have a blog! I can write a movie review!!" I go join the SO, who is standing in line to buy some popcorn. I do a recap, and a man in the next line over explains to us that it's in Theatre 15, and they aren't asking for credentials, only a name and affiliation. We decide we're too nervous (and maybe too moral) to try for it, and it's about five minutes before Prince Caspian is supposed to start, so no go. Well, actually, Prince Capsian wasn't finished yet, so we went and sat on a bench for a while, whereupon we realized that if we didn't try to see Indiana Jones—it's Indiana Jones !!!—then we would regret it. So we walked over to Theatre 15 with our popcorn and I told them we were from an Ohio State newspaper, and we walked right in.

Now, I promised a review, but, first, there's a slight problem, a dilemma if you will. See, I hate spoilers. I abhor them. I think people who spoil movies or TV shows without fair and ample warning should be drawn and quartered, or at least stripped of their right to enjoy any entertainment ever again. I don't read movie reviews because, if I know I want to see a movie ahead of time, why would I want to know what someone else has to say about it before I go see it?? I'll make up my own mind. And if I don't want to go see a movie, then why the hell would I be caring enough about it to read reviews?? It's just not logical. (And, no, I don't think that the first new Indiana Jones movie in 19 years will qualify for many under the third case of "and if I haven't heard about a film...")

As it happens, however, I happen to be dating someone who, while also having a strong aversion to spoilers, does not hold the same reservations towards movie reviews as I do. So the SO will be doing the actual review:

Indiana Jones and the Kingdom of the Crystal Skull is the first Indiana Jones movie to exist in the history created by the earlier films. I mean, did Indy ever talk about the stuff he'd already done before? The movies are pretty stand alone, right? There is, I believe, one little blink-and-you'll-miss-it reference to Raiders in Last Crusade, but that's it. The Indy we meet here, however, has done everything. He found the Ark of the Covenant. He found the whatever-they're-called stones. He found the Holy Grail. And he's done 20 more years worth of stuff that we didn't get to see. He fought in World War II, one way or another. He's done all this, and he's no longer afraid to talk about it. He's a guy starting to see the end of the tunnel and has learned that he likes telling his lifetime's worth of stories. This is not the Indiana Jones we met before, nor should it be. He's lived 20 more years, grown, maybe even learned a little bit since we saw him last.

This means, of course, that the movie takes place in the 50s, and if you manage to forget this fact, you'll be reminded as the film traverses every archetype (or should I say stereotype?) of the nostalgia decade before the end of the first reel. Shia LaBeouf does a reasonably good job of inhabiting one of those ----types. But not as good as Cate Blanchett, who, in her unending streak of impressing me more than I expect her to, may very well have crafted the best Indiana Jones villain ever from what is really an underwritten role. She's a wonder to behold, and she and her minions never quite manage to fall into the incompetent villain class, despite being constantly outsmarted by the heroes.

Now, I have to say something about the title. When I first heard it, my response was something like "'Crystal skull'? Really? I mean, seriously?" It really didn't seem like a sufficiently substantial object, particularly compared to the Ark or the Grail. But the movie sold me. It totally sold me. I don't want to say how exactly it does this for fear of spoilers, but it does.

My biggest complaint is that the movie sometimes seemed too eager to underdevelop a character or a dramatic situation in order to get back to another in a very long line of witty action sequences. I think that if you go in expecting the Second Coming of Spielberg, you'll be disappointed. This is not really an important film. It won't change the face of cinema as we know it like Raiders did, and it won't take Indiana Jones to a place he's never been before or will again like the Last Crusade did. All it will do is give us a few more events in the unusual life of Henry Jones, Jr. I suspect that nothing that occurs in Indy 4 is really so spectacular for him, which makes this new (older) Indy different, but it is fun to spend a few days walking around underneath his hat again.

An Engineer's Guide to Kitties

2008-04-25T14:06:00.002-04:00

To ensure it doesn't get too serious around here, here's some Friday afternoon fun:

Personally, I prefer the phrase "snuggle attack" to "corporal cuddling," though the alliteration in the latter is appealing. And, for the record, δ Carina is about 18 inches by at most 5 inches, for an aspect ratio of about 3.6; this is why she has graduated from "furball" to "furslinky."

Paper Summary: Metal-Rich Dwarf Galaxies

2008-04-22T12:50:00.000-04:00

Towards the last week of January, when I was hugely absorbed in trying to figure out a thesis proposal thing, a professor came into my office and started talking about the mass–metallicity relation. I knew about it, of course, but here was a new, simple idea: are the extreme outliers from this locus of galaxies real? In the spirit of a short "one month" project, it's now about three months later, and we've "finally" got a paper on said outliers on astro-ph. (I think this is a great example of: if anyone ever offers you a great idea, take it and run with it.)

So to back up a bit. What's this "mass–metallicity relation"? The short version is that a correlation exists between galaxy mass and metallicity such that the more massive a galaxy is, the more likely it is to be "metal rich." Originally this was the luminosity–metallicity relation, since how bright a galaxy is is much easier to measure than how massive it is, so on the right here I've plotted metallicity versus "absolute magnitude" in small grey points for a large sample of star-forming galaxies (remember: magnitudes are silly, so the right-hand side is brighter than the left-hand side, even though the numbers don't increase in that direction). Our outliers are, well, the larger red and green outliers from this relation; the different colors simply denote slightly different ways of selecting different subsamples. Astronomers being astronomers and not material scientists, when we say "metals" what we really mean is "any element which could not have been made in the Big Bang, i.e., basically anything not Hydrogen or Helium (or maybe Lithium but there's so little of that we'll completely ignore it)." There is of course a nice slew of caveats. The first is that the easiest way to measure the metallicity of galaxies is to limit ourselves to star-forming galaxies; all of those nice new young stars heat up the gas around them, and then as this gas cools it gives off emission lines. We can then look at the spectra of these galaxies and by measuring the how how strong various lines are relative to one another and combining it with some black magic (a.k.a. "spectral synthesis codes") we can measure the ratio of oxygen to hydrogen in a star-forming galaxy's gas. So I (and others!) basically use "metallicity" and "oxygen abundance" interchangeably, and, more precisely, I basically always mean "gas phase" abundance.

One of the interesting interchanges between theory and observation is that sometimes there will be some interesting observation (such as the obervation that galaxy mass and metallicity are correlated). So theorists will come up with a bunch of reasons why this is the case, and a few will even attempt to give explanations fo the scatter about the observed relation. A robust theory will also be able to explain seemingly strange galaxies: if a theory is able to explain why low mass galaxies have such low metallicities, then it should also be able to predict in what ways a low mass galaxy with high metallicity is different from its more mundane cousins. I spend a lot of the paper exploring various explanations (and then eliminating them) for why these galaxies could be so "weird," but I eventually hit upon one explanation which, in retrospect, is blindingly obvious.

The idea is that low mass galaxies have low metal abundances because they have low star formation rates and relatively high gas fractions (i.e., the fraction of their mass that is in gas rather than stars is large). An easy way to think of this is like so: stars turn hydrogen and helium into more massive elements (metals). As stars are formed, they the most massive ones die quickly, throwing their metal-rich selves back into the surrounding gas, thereby raising the metallicity of that gas. But a low star formation rate in a high gas fraction environment will not be making enough metals in order to fully pollute the gas around it, and so the fraction of metals in the gas will be relatively low. (This argument only really works for low-mass galaxies, but since those are the ones we're interested in, I'll ignore that subtlety for now.)

So how do you get high-metallicity low-mass galaxies? Well, presumably the galaxy would need either a very high star formation rate (so the massive stars can actually pollute the gas) or a very low gas fraction (so each supernova has a higher impact on the gas). We find that these outliers don't have unusually high star formation rates, so we conclude that they must have rather low gas fractions. But this is the same gas the stars are forming out of! So the star formation must not have very long left to go. A nice bit of supporting evidence for this scenario is the occasional mention in the literature that so-called "transition" dwarf galaxies tend to have low gas masses and higher-than-expected gas-phase metallicities; these galaxies are known as "transition" objects because they are between regular star-forming dwarfs and quiescent non-starforming dwarf galaxies. The especially neat part is that several of these galaxies have the star formation limited to their centers (like this galaxy to the left: blue in a galaxy is a sign of lots of young, recently formed stars). One way to interpret this is that star formation used to occur on all scales in this galaxy, but the gas has since been extinguished (or blown out of the galaxy) at the larger scales.

Passover

2008-04-20T14:48:00.002-04:00

I'm in San Francisco this weekend for my first celebration of Passover. As I've never observed a religious holiday in a purely secular setting (and, no, Christmas doesn't count), this should be fairly fun and educational. Growing up, I always thought Easter and Passover occured around roughly the same time of year, but of course this isn't strictly the case. This year Easter was really early: it falls on the first Sunday after the first full moon after the first day of Spring, which this year all happened to make Easter three days after the Vernal Equinox. And, of course, leave it to an astronomer to explain all of the intricate calendar calculations and relations between Easter, Orthodox Easter, Passover, and Rosh Hoshanah. Basically, the confusing arises when the Vernal Equinox is approximated to be (as opposed to basing these holidays on when the Vernal Equinox actually is).

2nd Blogiversary

2008-04-16T18:41:00.001-04:00

Today is apparently this blog's 2nd birthday. I'm too out of it right now to do anything special, mostly because I finally submitted the paper I've been working on for the last few months to ApJ (i.e., a journal) and the arXiv (it'll be up Thursday night and I'll probably write something real about it this weekend), and I've still go this "thesis proposal" thing to prepare for Friday. So, in the meantime, here is a word count breakdown of the paper. Your job is to guess the subject matter.

Word	Count
the	417
galaxy, galaxies	164
mass, masses, massive	105
metal, metallicity, metallicities	98
sample	78
we	76
star, star-forming, stellar	75
low	59
gas	41
correlation, relation	39
abundance, abundances	37
dwarf	30
relative, relatively	27
outlier	26
oxygen	22
less, more	22
e.g., i.e., vs.	20
seventeen, 17	18
therefore, thus, hence	17
effective, effectively	10
spurious, spuriously	6
pathological	2

Definitely a Link Dump

2008-04-07T20:59:00.001-04:00

I'm tired, and therefore you're not going to get a real blog post out of me. So here are some interesting and/or funny things I've seen on the internet lately.

Class and National Service as well as Social Class and Educational Access tackled at Uncertain Principles

And then there's Sean at Cosmic Variance discussing even more evidence for why funding and curriculum standards for public schools should be nationalized.

From Freshome we have a house that looks like a toilet and a sideboard with a glowy full moon

Are Homophobes Aroused by Homoeroticism? from Dispatches from the Culture Wars

a funny kitty:

A delightful discussion of typography and political campaigns, via Deadly Mantis

Hat tip to Blake for pointing me to the Relativity Song from everyone's favorite Max Tegmark and 8.033:

And finally, via the Friendly Atheist, a nice explanation of how Jesus and Tetris are really the same thing.

Brunch Review: Spagio's in Columbus, OH

2008-04-06T11:17:00.000-04:00

My brother was in town last weekend, and being inspired by my previous two brunch reviews, decided that some "Is it breakfast, or is it lunch?"-y goodness was in order. So last Sunday morning we went over to Spagio's in Grandview, the closest thing I have to a "default" brunch place in Columbus, and this Sunday morning (after visiting for a second weekend in a row!) he has reminded me that I never got around to writing up what I think of brunch at Spagio's.

First off, Spagio's is one of my favorite restaurants in Columbus. It is one of the default places several people in the astronomy department take visitors (colloquium speakers, prospective graduate students, and the like); I unequivocally recommend it for dinner. The restaurant is attached to a decent wine store, so the wine selection is understandably good (and unlike many restaurants, they have a decent list of wines they serve by the glass). The decor is kind of random: there are hammocks hanging from the ceiling (which certainly hundreds of people who have dined there never noticed), random art hanging on the walls (including a weird wooden sculpture of a pig's head and a napkin one of the restaurant's owner's [or the chef's?] friends spilled some wine on and then went to town on turning into Art), and generally just an eclectic collection of decorations which somehow jive together into a neat atmosphere. Pretty much everything I've tried there for dinner I've enjoyed, so it was a natural choice for a first attempt at brunch in Columbus.

So, brunch. Spagio's is a few doors down from Columbus's Stauf's Coffee, and so that is what they serve. Delicious. Unfortunately, this is Ohio, and so no alcohol can be served before 1pm. So much for a bloody Mary for my brother. My normal fare is the croissant French toast with maple cream cheese; oh gods it's so good. Last week I decided to try to jump out of my comfort zone, and I tried the steak and eggs. The steak was fine, but the eggs were kind of flaky and weird and I didn't end up eating them. My brother at least enjoyed his eggs a la maison ("it was food"), but generally I was unimpressed last week. But hey, if someone else is willing to pay for it, I wouldn't turn it down. Just stick to the French toast.

Another Peanut Star: This One's Yellow!

2008-04-02T10:26:00.001-04:00

This was actually discovered a few months ago, but now there's a press release and even a movie: a peanut-shaped binary star system has been discovered (with the LBT!) in the dwarf galaxy Holmberg IX, a companion to the beautiful spiral galaxy, M81:

And, yes, despite the unfortunate date chosen for the press release, this is a real star, and it is actually exciting. And I take full credit for the term "peanut star." Just please ignore the fact that the movie makes the stars look like they're being externally illuminated instead of, you know, generating their own light.

Proposing a Thesis Thing, Part the First

2008-03-28T20:25:00.000-04:00

Sometime in November or December I started writing a blog post (most of which is included in this one, with the tenses slightly changed) on how I have to do a thesis proposal this year and what all that entails. So this is going to be a roughly five month saga compressed into a multi-post few week funfest, seeing as how there's been this Date set for April 18 or somesuch.

As I alluded to at the time, I spent several days just after Thanksgiving at a conference in Tucson. One of the ironic aspects of attending a conference on galaxy and black hole evolution is that I have done very little work which could be construed as directly relating to most of the topics discussed those three days. And yet I kept being drawn to galaxy evolution and I kept saying it is what I want to work on... The idea, I supposed, was to actually get around to doing just that.

See, I was supposed to present a "thesis proposal" in February, as the next step in this whole getting a PhD thing (the previous step being the candidacy exam last summer). (Or so was the case at the time. April is the new February, apparently.) The thought of choosing a thesis topic somewhat terrifies me, mostly because of the stereotype that choosing a thesis topic is equivalent to choosing what I'll be working on for the rest of my life. My aversion to such a decision stems from the same aversion I have to say, traditional marriage: it's not that I can't see myself working on something for the rest of my life, it's that I wouldn't want to work on one thing to the exclusion of all else.

Luckily, real life isn't a pure manifestation of stereotypes, and what a "thesis" (or, more relevantly, a "thesis proposal") should be varies from advisor to advisor. If all goes as planned, I'm essentially halfway through graduate school (or at least I was in December), which means that I will be applying for jobs in (eep!) about a year and a half. My advisor seems to think that the thesis proposal should basically be a default plan for how I am going to write enough interesting papers in that year and a half so that people will want to give me a job. In other words, it's not so much what I will be doing, but what I can do if nothing else more interesting comes along. Yet, despite the seemingly nebulous nature of said proposal, I was still somewhat freaked out over the whole thing back in November. And December. And January. Then in February and March I just kind of ignored the problem, hoping it would go away ...

DoorKitty

2008-03-24T21:05:00.000-04:00

δ Carina recently figured out how to get on top of the bathroom door. I haven't seen her actually get onto the door, but she's pretty funny and proud of herself once she's up there. For your lolcat captioning pleasure...:

Brunch Review: L'Antibes in Columbus, OH

2008-03-23T14:05:00.001-04:00

This morning we tried out brunch at the fairly new French restaurant, L'Antibes, in the Short North. We were clever and realized yesterday that today is apparently a holiday on which lots of people like to have brunch out, so we even had reservations this morning. The restaurante is on the small side, but the atmosphere was pleasant and comfortable. The brunch menu price is fixed at $18 per person; this includes drinks (I recommend the orange juice even though it was very pulpy and I do not usually care for pulp; the coffee was also delicious). The meal itself consists for two courses; for the first course the choices are toast with fresh cream, butter, and jam (what I got), a cheese sampler, and a small salad (what the significant other got). For the second course, you have a choice of poached eggs, quiche (my selection), lobster potato gratin (what the SO got), and stuffed French toast. I was pleasantly surprised with the quiche, mostly because I don't think I've ever actually had quiche before; people have the tendancy to fill it up with ingredients I consider nasty. This was just eggs, cheese (asiago and goat), and boar bacon; simple yet light and fluffy and filling. The lobster potato gratin (a soupy mixture with a sunnyside up egg on top) was apparently a disappointment, unremarkable and "not that good" (but the entire thing was eaten).

The CMH Gourmand has also weighed in (despite a sore lack of brunch reviews over there), if you would like a more professional sounding review. The pictures are from a review by the Restaurant Widow; we cleverly forgot to snap some photos ourselves.

The Subprime Primer

2008-03-17T18:04:00.000-04:00

Your questions (and mine) about the subprime mortgage crisis answered...

Paper Writing

2008-03-13T11:56:00.001-04:00

The Sunday before last, I finally got to the point on my current ~~distraction~~ project where I could begin writing it up as a nice paper. That evening I started coughing, no big deal, but by Monday afternoon I was completely overcome with the flu. As it turned out, over half of the graduate students succumbed to the same flu ... and essentially all of us fell sick within 24 ours of each other. As we explained to the prospective graduate students visiting Thursday and Friday, one of the great things about the department here is the high degree of interconnectivity... so that everyone is put out by the plague simultaneously. So last week became an utter waste, but by Friday I was beginning to feel like myself again. Then between Friday morning and Saturday night, central Ohio was visited by about 20 inches of snow—the most snow in one storm here ever. I managed to dig myself out and get into the office on Sunday. And so for the last few days I've been trying to remember how to write a paper.

The quote of the week, I think, comes from Tuesday when I told a professor (with whom I have co-authored a paper) that I can't remember how to write papers. I said I was in my "wandering the halls" phase. The response? "No, no, you seem to be remembering just fine ... this is how you've done it before, if I recall." I couldn't argue with that.

Then Wednesday morning a link was sent my way, and I had no choice but to rearrange the books on my shelf.I discovered that a large fraction the textbooks I own are black or blue; apparently I am not a mathematician (because, as everyone knows, all math books are yellow). I don't know how long I will be able to keep the books like this; normally I sort by genre and then by size within genre (I think I'd need at least an order of magnitude more books before I considered sorting by author, which is apparently how God intended).

The amazing thing is that I'm actually making vague progress writing the paper; I'm almost finished filling everything in—including figures and tables—so soon I'll officially be at the "revision" stage... when I go back and redo everything so that it is at a quality level where I am not embarrassed to show the manuscript to my coauthors. Whee fun.

A Kitten's Decision Tree

2008-03-03T14:28:00.002-05:00

How δ Carina decides whether or not to attack something:
Basically, she wouldn't have attacked Iraq unless she was feeling hyper that day, and I'm not 100% looking forward to flipflop season.