Wednesday, August 31, 2011

The Future of Astronomy?

Let me start off by saying that I had a really, really bad day.

I started off by making a major mistake. After I made sure my program was still chugging along, I surfed the web for current outlooks on the astronomy job market. Yes, I'm an f-ing genius. It was, as so many post docs say, positively depressing. Too many PhDs, too little money, too little opportunities... etc.

Post docs spend the majority of their time stressing about the number of papers they publish. It's considered that any less than 1-2 papers a year is a death sentence for getting a faculty job, no matter how good their papers may be. Despite what most people say, in astronomy, quantity trumps quality.

Then, in a quirky twist of fate, I went to Science Coffee, where we briefly discussed a paper on applying economic principles to astronomy. The gist of the paper was about how the scientific community could gauge the "value" of a theory (though I assume this applies to most research projects in general). The value of a theory could be determined by such factors as growth rate in the field, number of faculty jobs, number of cited papers, etc. With this in mind, appropriate projects could be pursued, and grant money would be allocated to the projects deemed most valuable. Now, this paper in and of itself may not have much lasting impact. Most people in the room kind of snickered at it or dismissed it entirely, but it made me angry.

No. It made me really, really angry.

My idealized, rose-colored vision of how astronomy functions is quickly diminishing, and this paper is a symptom of it. With all this focus on publication rates, it's no wonder arXiv papers have become so boring. Nobody can tell me why their research is important, because nobody wants to do a risky project. Nobody wants to do a project that will take longer than 1-2 years to complete. That could impact publication rates! No, it's much better to choose a safe, non-threatening project that can be done will minimal effort. Plus, if it's safe, it's much easier to get that research grant approved.

This, in my opinion, has only one effect. It breeds conservatism and stagnation within the field.

Once upon a time, I thought scientists were the heroic people who did science for the love of science. In reality, scientists are forced to do science for the publications. I understand that research will always be impacted by what money-granting institution thinks is in vogue, but that's no reason to buy into it entirely. Yes, some major discoveries were intentional, but the vast majority of major discoveries came by accident. If we all knew where to look, don't you think we would have done it already?

Discoveries are built upon surprises and the unexplained. They are built upon innovation, creativity, and a healthy heap of luck. How can you put a number of publications on that? How do you define if this risk is good or bad?

I was once told that the hard work science demanded was rewarded when you got to be the first person in the world to understand something. Think about that feeling for a second. I wonder how much it happens anymore.

A part of me understands that astronomy is a field in contraction. The competition is so fierce for so few academic job openings, that nobody will dare go against the status quo. That would be career suicide. But some part of me wistfully thinks back to Agent Fox Mulder of the X-Files, who always pushed his wild theories because he knew he was onto something. It didn't matter what the people around him said, or how much he jeopardized his career. He was going to try and collect the proof he needed.

Corny, I know, but I think the spirit of it is beautiful.

Wednesday, August 24, 2011

Why Intrinsic Ability Does Not Matter

I'll let you in on a secret.

I am not naturally good at math. I am not naturally intelligent. If you were to put me on a distribution of general "smartness", I would be smack dab in the middle.

This is not easy for me to say.

In third grade, I remember being tested for the Gifted Program, which was just a group dedicated to teaching the best and brightest kids at an accelerated rate. Though I scored extremely high on the reading portion, I tested two grades below on mathematics. Needless to say, I did not get in.

I remember when I was told of my deficiency in math. At that time, I didn't want to be a scientist. I didn't want to be anything. To tell you the truth, I would have been perfectly happy to spend all my days reading. But, for some reason, my lack of mathematical ability bothered me. It truly, truly made me upset - not at the teachers, but at myself. So I went home and told my mother that I had to learn the subject, and that I would be willing to devote my entire summer to it if I had to.

I kept true to my word.

In high school, I consistently scored perfectly on anything written or literature based. I always scored consistently lower on math. It was a great source of shame for me, because by that time, I knew I wanted to go into science. What scientist isn't good at math? I knew that if I didn't understand math, the framework for how the universe works fundamentally, then my understanding of how the world works would be severely impaired. So I kept trying, and enrolled in the highest level math classes I could. By the time I graduated high school, I had taken two years of Calculus. Not shabby for someone who used to be two grades behind.

My friends at the time told me they admired my natural math ability. They said they couldn't ever do math because they weren't wired for it. They claimed people had to be born with the ability, because it couldn't be taught. I tried to tell them how wrong they were.

I now have a minor in Mathematics. I have more training in math than most people in the world. The thing is, I'm not naturally "wired" to do it. I just did it.

Now, I don't want to claim that intrinsic ability doesn't matter at all. It does. I will always have to work twice as hard to learn concepts or complete research. I positively suck at programming. I probably won't ever stand a chance getting a job in academia, because truly talented people work just as hard as I do. But you know what? I've made my peace with that. I went into a hard field because I like it and because I needed to at least try.

There comes a time in most people's lives when they realize that life isn't fair. Some people are born with it all - whether it be beauty, intelligence, charisma, or all these things. I don't know what separated me from my old friends, the ones who were content to throw their hands up in the air. I don't know why I was spurred into action, when so many people around me passively accepted their "inabilities". I don't know why knowledge, for it's own sake, was so important to me, but not necessarily to others. I usually give up pretty easily, to tell you the truth. Today, I could learn a lot from my younger self.

I don't know if there's a point to this, other than nothing should hamper your ability to learn. Don't believe for a second that anything is above your understanding - not math, not physics, not anything. Don't let other people make up your mind for you. It all comes down to what skills you actively pursue.

And though it may be above my level to be the best scientist, I can certainly become a good one. That counts for something.

Monday, August 15, 2011

If I’m So Smart, Why Did I Wear Pants Today?

Aaaaaaah . . . the start of a new semester is in a week. I feel strange now that I’m a second year grad student. I’m also a bit sad that once classes start, I’ll have to put a hold on watching the X-Files while eating rainbow sherbet.

It occurs to me that I haven’t written about actually being a grad student. It also occurs to me that this might be because it’s not really that interesting. But, unfortunately for you, this is what I’m going to attempt to do. So ha!

I wake up and it’s always hot. Really, really hot. . . . and humid sometimes. I decide today to wear pants instead of shorts, because I’m not really a shorts kind of person. I actually hate wearing shorts and flip-flops, but summers in Tucson are like the death throes of Sylvia Plath – you feel like your head is in an oven, frying your brain until you go slightly crazy with each passing day. So, I usually make due with the least amount of clothes I can live with. If I make it to my air-conditioned car before death, I can watch fried people on the street do stupid things. For instance, I saw a woman screaming to herself on campus today. Some may call her crazy, but I call her a “Native Tucsonian”.

When I make it to my office, I prove (like I always do) that I’m not as smart as I think I am. I volunteer to give two talks during the semester over email. Why? Because I can. Was that a smart thing to do? Absolutely not. Nonetheless, I notice that my email must be controlled by a secret government project, because the next time I look at the clock, it’s time for a meeting with my advisor.

Advisor meetings always go the same. They go something like this:
Advisor: Hello. How’s it going?
Me: I made progress! See?! See?! Please believe me . . . LOOK AT MY PLOTS!
Advisor: They look a little funny. Did you think of [insert easily foreseeable problem].
Me: Oh. Yes. I should have thought of that.
Advisor: Ok. See you later.
This takes 3 minutes (ok, I may be exaggerating a little here. It takes around 5 minutes).

After I get direction, the real work begins. It starts with me looking sadly at my iraf script (iraf is a computer language I use to do some of my work). Then I open up lots of internet browsers in search of something to fix my code. I get a headache within 20 minutes. However, it’s ok, because now it’s lunch time!

I walk through the scorching desert heat in search of food. I wish I had worn shorts instead of pants.

I get back into the office. I’m uncomfortable because my pants are now sticking to my legs. Ugh…. I hate that feeling. Now, where was I? Oh yes, trying to understand iraf… I get my headache back again. I curse and scream because iraf uses different parsers for the command line and its scripts. So, even though I find something that works on the command line, it doesn’t work in the script. After a couple of hours, I find out the weird little problem that kept my script from working. It was something about assigning structures before strings? Heck if I know . . .

I get tired of working. I visit another person’s office, steal their wheelie chair, and push myself in circles for half an hour. I make a lame joke and laugh for way too hard, way too long. It is at this insane moment that I decide I can tackle iraf again.

I run my program again. It doesn’t work, even though I changed nothing. I finally realize that iraf was made by the Devil . . . er, no . . . Astronomers . . . what’s the difference? I laugh out loud. I decide to go home. I walk to my car.

It’s really hot outside.

When I get home, I put the X-Files on. I change into my pajamas, eating rainbow sherbet. I write this blog. I’ll repeat this day tomorrow, and perhaps the day after that, but one thing will be different: I’m going to wear shorts instead of pants.

Tuesday, August 9, 2011

Thick Disk Formation and Finding Missing Baryons

I read a recent paper some days ago, entitled “Thick Disks of Edge-On Galaxies Seen Through the Spitzer Survey of Stellar Structure in Galaxies (S4G): Lair of Missing Baryons?” by Comeron et al. I decided to read this paper mainly because the authors were using the S4G survey, which is the same survey I'm using. The S4G survey is an infrared survey using 3.6 micron and 4.5 micron data from IRAC. These wavelengths are sensitive to older stellar populations and have reduced contamination from dust and star formation.

These authors looked at 46 edge on galaxies, to determine properties of the thick and thin disks. A thick disk in a galaxy is characterized as having a larger scale height (or, roughly, thicker cross section) than its flatter thin disk. The thick disk also tends to have older stars and a lower surface density (7% of that of the thin disk for the Milky Way). It's been a bit of a puzzle why these two disk populations exist, but an understanding of how the two disk components are related to galaxy formation will help us unravel clues to the processes that drive galactic evolution (hmmm... seems to be my favorite subject, but too bad! It's my blog!).

There are a couple of interesting things these authors found. First, they claim that thick disks may have a larger stellar population than previously thought, and second, they claim to have a better understanding of how thick disks formed.

Most of the paper is on the specifics of their model, which is way too complicated for a blog post. If you're interested in their modeling techniques, I suggest you read their paper. Long story short, the authors fit two stellar populations together to represent the thick and thin disks, Then, after they decided on what to assume for the numbers of small stars formed vs massive stars, they generated a mathematical description of how the luminosity of these galaxies should look like. They generated multiple models, assuming different stellar populations in the disks. Then, they simply compared those luminosity models to the actual data.

What they found was that the best fit to their models was a thick disk comprised of ¾ to as much as 3 times what we had previously thought, depending on which model was used. Of course, this may be highly model dependent, but all the models agreed that there is a higher stellar population in the thick disk. Now, why is this important? It's important because we haven't been able to account for all the universe's baryons. There was some speculation that the missing baryons were driven into the intergalactic medium from supernova feedback, but that scenario can't account for all the missing baryons. Perhaps this is the missing reservoir (hence the title of their paper!).

Also, the authors propose a formation scenario for thick disks. There are four different models for thick disk formation, which I'll abbreviate here:

Model 1: The clumpiness of galaxies can create overdensities that may perturb stellar orbits. These overdensities may come from spiral arms or molecular clouds. Astronomers do believe that young galaxies may have had a clumpier structure, but this model has difficulty describing the highest velocity stars.

Model 2: The young galaxies could have passed through dark matter clouds or other galaxies. This scenario, though, cannot produce a a thick enough thick disk when large quantities of gas is present. Also, these interactions usually produce a flared disk, which is not seen in the galaxies in this survey.

Model 3: Thick disk formation could have been a result of in situ star formation. The best candidate for this is . . . surprise . . . galactic mergers. The gas forming the thick disk would be dynamically hot from the merger, which could produce a thicker disk. The only problem with this model is that the accretion of external gas shrinks the disk, making it virtually indistinguishable from the thin disk. However, if you increase the mass in the thick disk, the net shrinkage would not be such a problem.

Model 4: Interactions with other galaxies may have donated stars via tidal stripping. However, this mechanism can't produce a large enough stellar population at present.

The authors suggest, in light of their observations, a thick disk formation scenario favoring in situ star formation. They believe that young protogalctic clusters may have merged, producing a hot disk of stars. Since they detected a higher population of thick disk stars, the later accretion of external material did not shrink the size of the thick disk by much. Then, once the galaxy aged and accreted cold gas, the thin disk was formed.

I was pleasantly surprised by this paper. I initially thought it would have nothing to do with my research, but in the end, it may. The conclusions seem to support galactic mergers as an important mechanism for galactic evolution, which is something I'm looking for. It would be interesting to see if thick disks vary depending on cluster environment, and, if so (or if not!), why that would be the case.