Tuesday, June 30, 2009

Preventing Failures In Communication

In our formal education as astronomers, we take courses on physics. We take courses on astronomy. We learn to perform research at the heels of our advisers. We devise and execute a research project. Then we are awarded our doctorate and unleashed on the world, supposedly ready to study the deepest secrets of the universe.

But there are some things we aren't taught or trained in, and yet are expected to be able to do, and be able to do well as professional astronomers. We are expected to be able to share our research with other astronomers in both written and verbal format, and we are expected to be able to teach university classes, which are usually filled with non-scientists who either need to fill a science requirement for graduation or who think the class might be interesting.

It therefore should be no surprise that so many astronomy classes are poorly taught, or that so many astronomy colloquia and seminars are dreadfully dull and unenlightening? Excellent researchers can take exciting topics and produce a lecture so boring that you wish for some minor disaster, like a fire alarm or tornado warning, to come along and give you a reason to flee the lecture hall.

I think that many of us astronomers have come to realize the importance of communications skills in astronomy, but so much of what we do is still just mimicking the teaching, lecturing, and writing styles of our peers and elders. Today I made an effort to try and engage the minds of younger astronomers (grad students and postdocs) on some of these issues. I led a discussion on giving effective scientific presentations.

I'd been thinking about this for a while, but was galvanized into action when one of my friends independently brought up the issue of presentations on the AstroBetter blog. I've been tinkering with my presentation style for some years, ever since stumbling across the Beyond Bullet Points website (a site based on one of many books on how to create better Powerpoint presentations) about 5 years ago. While I am far from an expert on effective communication, I wanted to spark discussion on the topic before we all get too set in our ways to change.

So, about one and a half dozen grad students and postdocs got together this afternoon, and we had some nice discussions on topics that, in retrospect, seem like no-brainers to consider: the audience, the goal of the talk, the venue, and style. I think that the wheels in people's heads started turning. And that was my goal, to get astronomers thinking about more than just their science when they go to prepare a colloquium or other presentation.

Now if we could just get more astronomers interested in learning about advances in education....

Monday, June 29, 2009

Don't put off until tomorrow what you can do today.

In yesterday's post, I presented a (somewhat too heavy, perhaps) parable about a guy who refused to pay the dollar cost of necessary repairs on his favorite car. In the end, his miserliness and pig-headedness not only cost him his car, but took out his friend's beloved car as well.

The analogy I want to draw is with the current debate in the U.S. Congress about the Waxman-Markey bill, the cap-and-trade program designed to reduce emissions of greenhouse gases and to combat global warming.

The Earth's climate is warming, and human activity (specifically, the release of greenhouse gases) is the cause. There is broad consensus among the worldwide scientific community on those two facts. No, it's not unanimous, but it is overwhelming.

Failing to reduce greenhouse gas emissions will have dramatic and, on the whole, very negative impacts on humans. Moreover, the worst effects will descend upon the poorest countries of the world, who are least able to deal with it. And, throughout human history, disease, famine and poverty nearly always lead to social unrest. In the age of the "Global War on Terror," we are deluding ourselves if we think that what happens in sub-Saharan Africa won't impact us in the United States.

The signs of climate change are all around us, and are increasing rapidly. Here in Texas, we've just had a nasty heat wave. The southwestern US is in a prolonged drought. Farmers in Australia are in the midst of a long drought that shows no signs of abating. Individually, none of these events is unprecedented, but the predictions of global climate change are that such wild swings in the weather will become more common. Each of these costs loads of money and costs human lives --- global warming is not just about polar bears and penguins, nor about poor people half a world away.

The Waxman-Markey bill will cost money. It's not cheap. For two decades now we've ignored increasing signs of global warming. Like poor Bob and his car engine in yesterday's story, we've waited too long, and the cost of action and repair is increasing.

Why now? Why not wait until this horrid economy is better? First, there's never an ideal time for change. When times are good, we don't feel the pressure. When times are bad, we naturally and rightly become more conservative. But the bad economy provides a hidden advantage. We have a workforce in need of jobs, and reducing CO2 emissions and increasing the use of green energy provides new jobs. It will cost money to train people, and families that have worked in the oil and coal industries for generations will have to change, too. That's not cheap, and many of those workers are among the most disadvantaged in our society. Again, that's not cheap.

But look at the estimated costs of the cap and trade bill. Estimates on the per-person cost vary wildly, but let's be pessimistic and take an expensive view. Say $1000/family per year, over five times the Congressional Budget Office's estimate. There are roughly 100 million families in the US, that's 100 billion dollars a year. That's a lot of money. But it is similar to the amount of money we are currently spending each year in Afghanistan and Iraq. If, as the majority of scientists, social scientists, and economists believe, global climate change is going to cause an increase in social unrest, then even an expensive cap and trade system will be less expensive than fighting future wars to protect ourselves. Further, most of us in the middle and upper class can easily recoup $1000 a year or more by driving slightly less (cutting our driving mileage by about 20% would do the trick) or by cutting out just a few luxuries -- we're talking less than $3 a day here!

In short, if we do not act and act now, we are only increasing the damage to the climate and drastically increasing the future costs for us and our children. And, not only that, but we are increasing the costs and dangers incurred by our allies who have already started to reduce their own emissions. We won't just hurt ourselves by inaction. We will hurt our friends, and we condemn the poorest of humankind to the worst of the effects. And why? Because we are too ignorant to believe the evidence in our face and too cheap to spend less than three lousy bucks a day to save many times that cost in the future? If that's the case, like Bob we deserve the wreck we are heading for. And, being bad citizens, we'll take everyone else with us.

Or, we can change. It will cost money, and the necessary lifestyle changes won't always be easy. But (to paraphrase the Six Million Dollar Man) gentlemen, we can rebuild our carbon-based economy. We have the technology. We have the capability to build a green economy. Better, stronger, faster, safer. And history will judge us kindly for such an action.

Sunday, June 28, 2009

The Parable of Bob and the UltraMeister 3000

Today I tell a parable, and tomorrow I'll give my meaning behind it.

We're going to follow the adventures of two normal American guys, Clark and Bob. Clark and Bob are good friends, and both have always wanted to own a high-end sports car. They save up their money, and when they have enough, they go to the dealer to buy the newest hot thing. The sports car comes with a new type of German engine, a 24-cylinder platinum-plated, gold-tipped titanium UltraMeister 3000. Both Clark and Bob are very happy, but a good $150k poorer.

When they pick up their Infinity+1s, the dealer admonishes them that the UltraMeister 3000 engine requires a special synthetic oil. "If you use normal 10W30 in this engine, the engine won't last 100,000 miles," the dealer says. "With the synthetic, you are guaranteed at least 200,000 miles. We can do the oil changes for you; it'll cost $99.99, including oil and labor."

Clark and Bob drive off happy until it is time for their first oil change. Clark takes the car to his mechanic, Ed, and asks Ed if he really needs the synthetic oil. After all, Ed routinely changes the oil in Clark's Family Truckster station wagon. The Family Truckster is up to 180,000 miles and uses normal oil, with a typical oil change costing just $24.99.

Ed looks Clark in the eye and says, "I've read all about the UltraMeisters. They really do need that high-end oil. I can change the oil, but it'll cost $79.99."

"Why so much?" Clark asks.

"The oil ain't cheap. And I needed special training on the new engines, and it was expensive. I have to pass the cost on. But I guarantee that the engine will last 200,000 miles."

So, Clark decides to bite the bullet and pay up for the synthetic oil change.

Meanwhile, Bob goes to his mechanic, Gus, and asks about an oil change.

Gus is an honest mechanic who always wants to give his customers good service at the lowest possible cost. Because of this, Gus wasn't able to afford the UltraMeister 3000 training course that Ed went to. "You don't need the synthetic," says Gus.

"Really?" Bob asks.

"Yup," drawls Gus. "I've been working on cars for 20 years, my dad was a mechanic all his life, and my grandfather was the first mechanic in town. Cars come and go, but an engine's an engine. Those dealers just want your money, as do the oil companies. The government's even putting a special tax on those synthetics. Besides, those engines are new, and they just don't have enough data on them yet to show that nothing's wrong. I'll just give you the standard oil for the usual price, $24.99." And so Gus changes Bob's oil.

Later, Bob and Clark are talking. Clark tells Bob that he better use the expensive oil, but Bob reiterates Gus's accusations that the dealers, oil companies, and government are all in it together to get higher profits.

Time goes on. Every 3000 miles, Clark gets an expensive oil change, and Bob gets the cheap one. After about 50,000 miles or so, Bob notices that his engine doesn't sound as smooth as it once did. He wonders if he should get the synthetic oil, but his daughter is about to go to college, and he needs the money for tuition.

Clark also has a daughter in college, and hates having to pay for the oil changes. But then he realizes that if he skips his morning gourmet coffee once a week, he saves enough money to pay for the synthetic oil.

Months later, Bob is watching his favorite car show on TV, Top Gear. The show is reviewing the UltraMeister 3000 engine series, and they are very pleased. But then Hammond intones, "The only thing about this car is that you have to use this special synthetic oil, or you'll ruin the engine in just 100,000 miles."

Bob, feeling spooked, takes his car in to the dealer. The dealer looks at the engine and says that the pistons are showing signs of wear due to his use of the cheap oil. They urge Bob to replace the pistons and to start using the synthetic oil. Price for piston replacement: a cool $15,000.

Bob is worried, but he can't afford new pistons at the moment. The economy is bad and he's worried for his job. Clark convinces Bob to take the car to Clark's mechanic for a second opinion. Ed agrees with the dealer that the pistons need replaced and that Bob should use the synthetic oil. "At least get the synthetic oil, that will slow the damage," Ed urges Bob.

But Bob is still worried about the cost of the synthetic oil, so Bob takes his car back to Gus for a third opinion. Gus says, "Ain't nothing wrong with the pistons; you just need a transmission flush and to use a slightly higher octane of fuel. Those dealers are just out to get you, I'm telling you!"

Bob is uncertain what to do. But Gus is a good mechanic and has never lied to Bob before, so Bob follows Gus's advice. And, with the higher octane fuel, the car does seem to be driving better. Seems that the dealer and Ed were just out to take Bob's money after all.

After about 90,000 miles, Bob's engine really starts acting up. Gus replaces all the gaskets, hoses and valves he can think of, but the engine still isn't running smoothly.

Bob calls in to Car Talk to ask their opinion. Tom and Ray ask, "Have you been using the synthetic oil?" Bob demurs. Tom says, "Bob, I hate to tell you this, but the engines ruined." Ray chimes in, "I fear I agree, Bob. Didn't your mechanic tell you that you should use the synthetic?"

A few thousand miles later, Bob and Clark take their cars for a joyride on a sunny afternoon. Bob is driving alongside Clark on a deserted road when Bob's UltraMeister 3000 finally gives up and freezes. Bob loses control of his car and veers into Clark. Both cars run off the side of the road and are totalled. Bob and Clark survive, but take several weeks to recover from their injuries.

So, who's at fault here? Is it Ed and the dealer for wanting so much money for an oil change? Is it Gus for his well-meaning but misinformed/ignorant views on a subject that should have been his area of expertise? Or is it Bob, who loved his car, who wanted to take care of it, but who kept putting off costly service until it was too late? And what about poor Clark? He took proper care of his car, but due to his friend's miserliness, Clark lost his beloved car, too.

Certainly none of the parties involved intended for Bob to ruin his engine and crash his car. But Bob could have avoided all of the trouble if he'd payed a little extra money and had critically considered the different advice he was given.

Tomorrow, we'll talk about my meaning behind this sad tale.

Tuesday, June 23, 2009

In defense of "wasteful" science

Several times a year, news stories come out about how the government is "wasting" money on science projects that are "stupid." I'll admit, at first glance, these projects can seem silly, and perhaps some of them are. But many aren't. Let's look a little closer.

Last week, news came out on a $423,500 study funded by the National Institutes of Health on "why men don't like to wear condoms." Sounds like a lot of money, and it sounds like a question many people think they know the answer to. So, why should we spend money studying it? Here are a few points I think are relevant and should be considered whenever we feel like railing against specific scientific projects:

Consider a cost-benefit analysis. Sexually-transmitted diseases, NOT including HIV/AIDS, cost Americans $10 billion every year. In comparison, this study costs $0.0004235 billion. If the results of this study can just decrease the incidence of STDs by 0.04%, an insignificant and probably undetectable drop, then it pays for itself. If it can cause a borderline significant drop of a percent, then it pays for itself 25 times over. I've also heard complaints about "wasteful" spending on science like studies of wildflowers and weeds, yet understanding their biology can lead to better (more productive, cheaper, lower-chemical) agriculture; again, this can be a many-fold benefit in cost.

The questions posed in "wasteful" science are often deceptively simple. There are many deeper underlying issues that not only impact public health, but also could impact broader areas of health and behavioral science. Why do people engage in risky behavior? Is it a lack of education about the risks? Is it a misperception by the man about the level of risk? What fraction of people consider the costs (not just health costs, but potential child support costs and other potential costs of the behavior)? And why does the brain so often lead us to overrule significant risks for short term pleasure? I'd argue that none of these questions have easy answers, and yet they all have implications far beyond this study.

Summaries of projects are usually dumbed-down. When we propose for funding from a federal agency, we are supposed to provide a title and short abstract that are understandable to non-specialists. Most of us (myself included) are pretty lousy at writing good abstracts, and overly-simplified descriptions of the experiments are presented, and the important underlying issues being studied are often forgotten or downplayed because we consider them "too complex" do describe in 250 words or less.

People cost money. A lot of money. Most of the costs of a grant go to paying for people (exceptions being grants that are used to pay for labs or equipment; in astronomy these tend to be different pots of money). Let me price out a generic research project, a three-year study of some really cool bit of astronomy.

  • The primary investigator is likely a faculty member; universities tend to pay 9 months of salary, and we have to cover the rest out of grants. Our grants also have to cover our own costs of benefits. Let's say that Professor Y earns $75k over 12 months with a benefits rate of 30%. 3 months of salary is $18750, benefits are $5625; multiply that by the 3-year duration, and the cost comes to $73125.
  • Let's add on a postdoc, who will do most of the research. Let's pay her $45k/year. Over three years, and including 30% benefits, that comes to $175500.
  • Let's pay for a grad student, too. A grad student will make about $25k in salary (I'm going to pay her well over the summer), plus 30% benefits, plus tuition costs (this is a state university, so tuition is roughly $10k/yr, including summer tuition). Total cost, $136500.
  • Ooh, shall we add an undergrad? They're cheap, we only have to pay him summer salary plus benefits. Let's see, $10/hr, 40 hrs a week, 8 weeks of summer, plus benefits comes to $12480 over three years.
  • Okay, now travel and publications. Let's say that the faculty, postdoc, and grad student go to one domestic and one foreign trip each every year. These can be conferences or observing runs. And let's force them to travel dirt cheap. That's about $1500 per domestic trip, and $2500 per foreign trip, so $36k over 3 years. We have to pay to publish our papers. Let's say one paper a year, 10 pages for a paper, at a cost of $125 a page. That's pretty standard. $3750.
  • Subtotal: $437355.
  • Overhead. Universities and research institutes take a cut of every expenditure; this is called overhead; it's like a tax. Typical rates can run from 50% (for every dollar I spend, the University takes $0.50 for their own use) to 100% or even 150%. This money goes to pay administrative salaries, pays for electricity and internet, water, janitorial staff, etc. Overhead is used to help keep tuition down, so it's a necessary evil. Not all costs are charged overhead, but what is charged varies from place to place. To make this easy for me to calculate, let's say overhead is a lower-than-normal 35%, but covers everything. Overhead costs are therefore $437355 x 0.35 = $153074.
  • Grand Total: $590429
In short, a typical, not-too-extravagant three-year research project is going to cost over $500k; this one costs $600k. That's just the way it goes. The condom research project is $430k over two years, akin to $645k over three years. That cost doesn't sound unusual or unreasonable.

Put things in perspective. The president's 2010 budget projects a deficit of $1.258 trillion dollars. If we eliminated this "wasteful" project on male condom use, then the budget deficit would be $1.25799966 trillion. The proposed budget in 2010 for the National Institutes of Health and National Science Foundation is roughly $40 billion. If we fully eliminate the NIH and the NSF from the federal budget, then the deficit will drop to $1.218 trillion. That's a minuscule change.

Funding proposals are generally quite rigorous and almost always thoroughly reviewed. I can't just go to the NSF and give them a 30-second pitch for a half million dollars. Good proposals take months to prepare, are often dozens of pages long, and are reviewed by a committee of experts that are carefully screened to remove friends and colleagues of the proposer. Proposals are judged on their scientific merits and weighed against other proposals form competing teams. Only about a quarter of astronomy proposals get a single penny. I suspect that things are at least as difficult in the medical sciences. In short, I can't come up with any dumb idea and get money thrown at me. I have to convince people that what I want to do is important, likely to succeed, and a good cost value. Yes, it may sometimes be possible to pull the wool over a committee's eyes or make end runs around the process (such as with a Congressional earmark), but this is actually quite rare and frowned upon.

There are things that we scientists need to do better. We must do a better job relating our science to the general public. Many scientists are not great communicators, but there are some excellent educators among us. We should hire them (adding another month's salary to our grant costs) and have them help us with public outreach. The taxpayer has a right to know what we are doing with their money, and deserves a better explanation than what we (myself included) often provide. We also need to make sure that we are keeping costs as low as possible. Many scientists do this; I know several who forgo summer salary or accept reduced salary in order to cut costs, even in good economic times. With some hardships, we can probably cut costs on publishing and travel. But the largest expense in many research grants remains salary, and it is really hard to bring that down. We also need to make our review process as thorough and transparent as we can. I know that the NSF works hard on this point; perhaps we need to spend some money educating the public on how we hold ourselves accountable to strict scientific standards.

So, the next time you see a news story lambasting a scientist for some wasteful-sounding project, think critically about it. Think about the deeper issues the science may actually be addressing. Scientific research is always far more complex than a three-sentence summary that has been digested by the press. This doesn't mean that there isn't waste, and it doesn't mean that every project that receives funding is actually worthwhile. But given the discipline and checks and balances involved in obtaining a grant, the scientist deserves at least a little respect and consideration, certainly more than a fraction of one newspaper column of facts skimmed from an abstract and a couple of 1-sentence quotes from the two sides of the argument.

Monday, June 22, 2009

More Citizen Science in the news: The Central Texas Astronomical Society

As I've mentioned before, the white dwarf research group of which I'm a member collaborates with local citizen scientists, primarily the Central Texas Astronomical Society, CTAS. Their current president, Dean Chandler, has helped us through some thorny instrumental problems, and many of their members (including Dean and Willie Strickland) have helped us with observing, both at our McDonald 2.1-meter Struve Telescope and with their own Paul and Jane Meyer Observatory outside of Temple, TX. (CTAS members, if you've helped us with some observing, feel free to write your names in the comments section or to send me an angry email lambasting me for not mentioning you. You deserve credit for the research and service that you do.)

Anyway, CTAS has finally received some press attention for the work that they've done. A couple of weeks ago, the Waco Tribune wrote an article talking about CTAS and their participation in professional astronomy research; the story was picked up by Austin's News 8 channel and included on their telecast last Friday; you can watch the video of that news story from the News 8 story.

In addition to their help with our white dwarf research, CTAS also works with many middle- and high-school students on science projects. In 2008, one of their middle schools students, Zane Foster, won first place in the Physics and Astronomy Junior (i.e., middle school) Division of the Texas Science and Engineering Fair for a research project on extrasolar planets that he did with the CTAS telescopes and their mentoring.

Way to go, CTAS!

Saturday, June 20, 2009

Speaking of teenagers...

I listen to several different podcasts as I'm commuting to and from work, and when I'm driving around town. Normally I am only half-listening; there's only so many discussions of the economy I can stand before I'm irrecoverably melancholy.

But today, on my way back from taking the recycling in (my apartment complex doesn't recycle anything), I heard something to the effect of, "When you think supernova, do you think early 1970s Chevy, maybe with the carburetor bored out and flames on the front quarter panels? Or do you think white dwarf? If you know enough about this stuff to know that what I just said about the dwarf isn't offensive... stick around." Well, of course I was going to stick around. Supernovae and white dwarfs are my job! I was thinking I might hear the voice of one of my friends on national TV. Wouldn't that be cool?

But I heard something better than one of my friends. I heard an interview with Caroline Moore, a New York teenager who, acting as a citizen scientist, discovered a supernova. And not just any supernova, but a really weird one. I'd read stories of Moore's discovery over the past couple of weeks, but since I was vacationing, I didn't blog about it. I've embedded the interview below.

What I find compelling about this story is not just that a weird supernova was discovered, and not just that it was discovered by a citizen scientist, and not just that it was discovered by a teenager, and not just that the teenager is, unsurprisingly, well-adjusted and not some stereotypical geek. It's the combination of all of these things. It shows that any committed person can contribute important observations to astronomy without having to becoming a hermit who spends every night squirreled away in a remote observatory and every day polishing his next mirror. And it shows that you, too, can help contribute to astronomy, even without training in solving partial differential equations and a knack for general relativity. So, if you have an interest in astronomy, get off your duff and pitch in! We've got the perfect opportunity coming up soon, as well as many, many ongoing efforts.

Way to go, Caroline! Here's hoping that whatever you go on to do in life, you keep looking up. We need the help.


Thursday, June 18, 2009

Hubble Space Telecope's new computer is acting up

A few minutes ago, the Hubble Space Telescope's Public Affairs Office tweeted that a mystifying problem has arisen with the Hubble's new Science Instrument Command and Data Handler (SI C&DH) that was installed during last month's repair mission. For the gory details, you can read their press release here.

But, in short, the SI C&DH is a computer that runs the science cameras; it controls the cameras and formats the science data for return to Earth. The original SI C&DH failed last September, leading to the 6+ month delay in the repair mission. In the meantime, the backup SI C&DH was booted up and did the job just fine. During the repair mission, a new SI C&DH (actually a spare that had been on Earth and was rebuilt for use in space) replaced the failed one.

Since the Hubble repair mission, the telescope has not been taking science pictures. It has been slowly running through checks of all the new instruments. This is taking a long but not unexpected amount of time. Virtually every camera was replaced or repaired, the new SI C&DH was installed, the new batteries needed to be charged up, and new insulation changed the thermal properties of the telescope, so the checkout has been deliberately slow and methodical.

The problem with the SI C&DH is that it unexpectedly started returning zeroes for all data. The SI C&DH claimed that it had placed all the instruments into safe mode (a protective mode for when something goes wrong), but Hubble's main computer showed that the instruments were not in safe mode. NASA rebooted the SI C&DH, which then seemed to be working, but to be cautious all of the instruments have been put into safe mode manually until the computer problem can be tracked down.

To me it sounds like the SI C&DH went into teenager mode. I can just hear Hubble's main computer talking to the SI C&DH:

Hubble: What'd you do today?

SI C&DH: Nothing.

Hubble: Did the Imaging Spectrograph leave any data for me?

SI C&DH: No.

Hubble: What'd you learn from the Advanced Camera for Surveys?

SI C&DH: Nothing.

Hubble: Did you place COS in safe mode like I asked?

SI C&DH: Uh-huh.

Hubble looks and sees COS blinking and whirring on the shelf.

Hubble: Did you really?

SI C&DH: Yeah.

COS continues to blink and emits a little chime.

Hubble: No you didn't! Now I'm going to have to reboot you in the rear. And you are grounded until NASA calls home and we can figure out what to do about you! Those astronauts risked their life and limb to make you happy and comfortable, and all you can do is mope around and complain about how miserable you are. Well, you'd better shape up or else we're going to shut you down and put the spare data handler in charge. And... Don't you dare glare at me like that!

In short, I'm not worried. Yet. Some analysis, some new software, and maybe the SI C&DH will grow up into a fine young data handler.

Tuesday, June 16, 2009

Participate in astronomical science this fall!

One of the great things about astronomy is how interested the public is in what we do. Whether it be pretty Hubble pictures, the Big Bang, black holes, or aliens, it seems that just about everyone always has lots of questions to ask.

What many people don't realize is that you don't need a space telescope or a PhD to participate in astronomy research. "Citizen scientists" (often called amateur astronomers) study variable stars, find new comets, discover supernovae, and look for extrasolar planets all the time. They help in the search for extraterrestrial intelligence and in classifying galaxies. They've even help us professional astronomers with our instrumentation. So much science wouldn't get done without the citizen science.

As part of the International Year of Astronomy 2009, a large observing campaign is being developed to monitor a strange variable star: epsilon Aurigae. Every one of you are invited and encouraged to help us study this strange star!

Epsilon Aurigae is a third-magnitude (moderately-bright) star in the constellation Auriga, the charioteer. Its name means that the stellar cartographer Johann Bayer considered it the 5th brightest star in the constellation (alpha Aurigae being the brightest, beta Aurigae the second-brightest, and so on.) Every 27 years, the star dims for about 650 days due to an eclipse.

Many stars dim regularly due to eclipses. Binary stars sometimes pass in front of each other (the star Algol in Perseus is one of the most famous examples), and many extrasolar planets were discovered by their eclipsing of a parent star. So, why are astronomers interested in epsilon Aurigae?

This star's eclipses are weird. Most eclipses last a few hours to a few days, but a 650-day eclipse is odd. In fact, the size of the object causing the eclipse in epsilon Aurigae would have to be much larger than any known star! Also, the shape of the eclipse is funny. Here's a plot of the brightness of the star NN Serpentis, a white dwarf star eclipsed regularly by a red dwarf star:

Light curve of NN Serpentis

Image credit: European Southern Observatory

The brightness of the star drops pretty rapidly, hits a flat bottom, and then bounces back up to the starting level (the little up-and-down fluctuations you see are all errors in the measurements, not variations in the star itself). This is because the bright star is eclipsed by a fainter star; during the eclipse, we only see the fainter star. Now the light curves of eclipsing binary stars aren't always this dramatic, but they all look about the same: a smooth drop to minimum light, a flat or rounded bottom, and a smooth rise to the starting level. And, even more importantly, every eclipse is the same. Now, look at the light curve of epsilon Aurigae:

epsilon Aurigae eclipses

Image Credit: Citizensky.org

It has a long, jagged drop to minimum light, then gets a little brighter, then gets a little fainter, and then slowly and jaggedly gets bright again. And these jagged appearances aren't errors; they're real. Also, the length of the eclipse is changing, and has been getting shorter. Stars and planets alone can't make those variations! Something else is going on.

There are many ideas as to what is happening here, but with only one chance to get data every 27 years, these mysteries are slow to clear up. So, that's where you all come in. Starting in early August, epsilon Aurigae will begin to go into eclipse again. With careful observation, you should be able to notice the dimming of this star over several months with your own eye; if you have a telescope with a digital camera, this dimming should be easy to measure. AND, epsilon Aurigae is too bright to observe with most professional telescopes. In other words, citizen scientists can make just as much headway in understanding this star as professional astronomers can. And, even if you don't have a telescope, you can still use your own eye to see this mysterious star's eclipse. So, anybody can participate! AND, even better, since the eclipse takes hundreds of days, you won't miss much, even if you have cloudy skies for a week or two.

To learn more about epsilon Aurigae and how you can watch the eclipse and even contribute to scientific observations, go to www.citizensky.org, read up on the project, and register to help!

Monday, June 15, 2009

Building Planets, Part 2

I am returning tomorrow from vacation. In the meantime, here's a continuation of guest author Joel Green's discussion on his work in star and planet formation. Joel will be writing more in the future as his time allows.

Anyone familiar with the beautiful artist conceptions of the Milky Way might picture our galaxy as a spinning ceiling fan of stars, with the outer edges of the arms trailing off behind. This picture seems a little strange upon consideration: why are there no stars in between the arms?

Artists Conception of the Milky Way seen from above

Image Credit: NASA/JPL-Caltech/R. Hurt

The answer is that there are stars there. Spiral arms represent compression waves – shocks of great magnitude orbiting the bulge of our galaxy. The arms are illuminated by star formation as the great windmilling shock brushes the gas and causes compression and expansion, stirring up the material. The Galactic Ceiling Fan turns once 500 million years or so; the Milky Way is about 20 orbits old. In Galactic years, we are in our infancy!

This compression cascades down from the largest size scales through clusters and associations down to individual star-forming regions known as molecular clouds – so named for their abundance of molecular hydrogen (H2) gas. There are other less abundant elements in these regions as well, cast out by dying stars of earlier generations, and interstellar dust in a pristine state. These clouds are the sites of star birth in groups of a few to a few thousand at a time.

The Orion Nebula as seen by the Hubble Space Telescope

The Orion Nebula as observed by the Hubble Space Telescope.

When instabilities, shocks, or turbulence stir up a quiescent cloud, some small parcel of the gas will be forced closer together. Because gravity is always an attractive force and gets stronger the closer things come together, an initial clump of gas and dust will continue to compress and draw in all the nearby material as it spirals into a more solid core that will eventually yield a star and, in all likelihood, a planetary system.

As the material spirals inward, it spins up faster. This is the same reason that dancers can suddenly spin faster if they pull their extended arms back to their body – the same amount of angular momentum transported to a tighter ring around the center leads to a faster orbit. So any particle with even the tiniest initial angular at large distances from the core will orbit very quickly when it is close to the star, and if there is a slightly preferred direction, then the core will begin to spin under all the impacts of these particles raining down on it. If the core were to absorb all of this energy without any release, it would spin so quickly and violently that it would blow itself apart, and star formation would be impossible. Instead, much of the momentum is carried off in the form of laser-like columns of jets shot out from the north and south pole of the spinning core, blasting into the environment.

Hubble Space Telescope image of Herbig-Haro 47

A Hubble Space Telescope image of HH 47. The source protostar is veiled in the center of the two symmetric flows.
Image Credit: STSci / NASA

Let’s pause for a moment in our slow zoom to the protostar, and back up to that initial clump. How did it get compressed? We have already seen that large-scale movement on the galactic scale can cause galaxy-wide compression, but how does this occur in an individual cloud? Judging from recent studies, it would seem that the causes of these clumps are actually TOO numerous. It is suspected that just by existing, molecular clouds have enough inherent turbulence to trigger star formation (usually referred to as “spontaneous” star formation). But there are smaller scale triggers, and we can actually observe these in action. For my thesis, I used the Spitzer Space Telescope to study a particularly hot and violent jet launched by a protostar, and traced its path through the Cepheus A molecular cloud, a mere 2000 light years from our doorstep.

To be continued...

Monday, June 08, 2009

Building Planets

Artist's conception of star formation around EX Lupi
Artist’s conception: EX Lupi builds its planetary system out of its cirumstellar disk.
Note: I'm away on vacation right now. This blog post was authored by my friend and colleague Joel Green, a postdoc at the University of Texas at Austin.

I’m in planet construction.

When I’m out at a bar, I see that people in the real world have business cards. I’m now designing a business card with a hardhat on it. This might prove very handy should I ever run into Slartibartfast or anyone else from Magrathea.

But in practical terms – remember, this is practical for an astronomer -- what I study is the assembly of solar systems, born out of gas and dust inside of a giant stellar nursery, alongside a new generation.

Stars form in clusters; the light from star formation in other galaxies can be picked up en masse by our telescopes. Except for some new studies of the very nearest of our satellite galaxies (in particular the Large and Small Magellanic Clouds), we can infer very broad properties from these observations. And these large-scale questions are very interesting: what is the general rate of star formation? How is it distributed around a galaxy? Does star formation occur spontaneously (via some sort of small-scale turbulence) where gas clusters, or does it require a triggering event like a giant supernova or a local shockwave?

Spitzer image of star formation in the constellation Serpens
Spitzer-IRAC image of a cluster of stars forming in Serpens.
Image credit:

But I don’t pay attention to other galaxies; I like to see the individual stars, and watch them develop. Of course I won’t live long enough to see an individual star go through its life cycle over millions or billions of years (in fact, some stars are so small that they can survive to several times the current age of the Universe). So rather than watching a single star, I collect data on thousands of stars that are in different stages of their life cycle, focusing principally on stars that are in their infancy -- less than about 25 million years old, all the way down to stars that are in their first 10,000 years. Some of these are hardly even definable as stars, rather as slowly compressing agglomerations of gas and dust surrounded by slowly spiraling and infalling material.

I study star formation that occurs in the local region, within a mere kiloparsec of our Sun. A kiloparsec is 3260 light years, or 19,000 trillion miles. I realize this sounds like a long way, but consider that our galaxy is perhaps 25,000 light years across. Our local group of galaxies is perhaps 2 million light years in extent. The observable Universe is 14 billion light years across. So really we are talking about a stone’s throw away; a kiloparsec hardly even gets us out of our local spiral arm, the Orion Arm, and its nearest neighbors.

So really this is just our backyard. Yet within this region we see stars of all ages and masses, of differing compositions and in a wide variety of local environments. All of these factors contribute to the development of a solar system; we survey these systems to disentangle these factors, much as doctors do in pharmaceutical studies.

The reason why we look at nearby stars, rather than surveying the galaxy, is simple. We want to be able to see them! Telescope time is precious, and we want to have as large of a sample size as possible. The instrument that we used to obtain this data, the Spitzer Space Telescope, just completed its 5 and a half year mission on May 15th, 2009. There is no instrument currently planned that will be able to examine the inner portions of solar systems to the extent that Spitzer could, and now we are left with a grand archive on which to conduct our studies.

Spitzer being assembled in 2003
Spitzer being assembled before launch in August 2003.
Image Credit:
Russ Underwood, Lockheed Martin Space Systems

Astrophotography Contest!

Discover Magazine and Celestron are sponsoring Capture the Universe, an astrophotography contest; Phil Plait, a.k.a. the Bad Astronomer, is the judge of this venture. The main rules: your images must be taken on Celestron equipment, and the due date is June 30 (of course there are more). Prizes include new telescopes!

More details and links to the full rules, prize list, and entry forms can be found here and on the main contest website.

Too bad I can't enter my Hubble pictures.

Wednesday, June 03, 2009

The need for critical thinking

This past weekend, I was working on a telescope proposal at a nearby coffeehouse, and a couple of young folks (high school, I think) were at the next table over, working together on a research project. I won't mention the topic, because that isn't important and would be distracting, but it was science-related, and I have some knowledge of the area.

I overheard much of their work, because they were fairly loud, and the discussion quickly grabbed my attention. These people were looking up a topic on the internet. After a short time one of the kids exclaimed, "All of these experts agree on the answer, but it doesn't make sense to me. How could so many experts be wrong?"

Now I realize that there are a lot of "experts" on the internet who can agree on the answer to a problem and yet be wrong, and I don't know which "experts" these students were reading. In this case, the experts were expressing the prevailing wisdom on the topic. Yet the students immediately jumped to the conclusion that everyone else was wrong, and they were right. They didn't even ask each other why the experts held the opinions that they did. To these two students, the fact that they did not understand the line of reasoning was proof that everyone else was wrong.

In graduate school, I made this mistake once. I was reading a paper on galaxy dynamics, and the authors were using an analysis technique I'd never heard of. In fact, it seemed almost magical. So I thought that it was poor science, and I expressed this opinion to a postdoc over coffee. The postdoc told me that the paper was actually excellent work, and that I should think about what the authors were doing. So, I went back to first principles, thought through the issue, and quickly came to realize that the technique was simple, elegant, and very powerful. I was the one who was guilty of poor science, not the authors.

That experience was an important lesson for me: just because I don't understand an argument doesn't mean that the argument is wrong. Maybe I have holes in my knowledge, maybe the argument was not well-made. On the converse side, a fallacious argument can often seem reasonable and very eloquent. Only by critically considering an argument and its supporting facts can we develop a well-informed opinion on a subject.

Critical reasoning is crucial to the continued success and viability of our society. Our gut feelings and initial impressions are often wrong and can lead us to make poor decisions. Blindly believing what we hear, even if it is a statement by a very smart person, also leads us astray. (For example, Einstein struggled with the concepts of quantum mechanics for much of his life; if everyone had followed his initial impressions that quantum mechanics was wrong, we wouldn't have much of today's technology.)

Poor reasoning and logic skills are dangerous. Lack of critical thinking has led us into wars. It leads us to inadvertently place others and our loved ones in mortal peril. It all-too-often costs us our own lives.

Reasoning and logic needs to be taught; it is not a natural skill for most people. I think it is often left out of school curricula, because a discussion of the fallacies of the straw-man argument does not, at face value, seem as important as reading, writing, and arithmetic (even though logic underlies all three!). But being able to recognize fallacious reasoning, being able to filter the flood of information around us, and being open to new ideas we've never considered before is as crucial as any of the topics covered in these courses. And, based on my experience at the coffee house, it is a skill lacking in society.

Tuesday, June 02, 2009


I'm off today for two weeks of vacation in the great American West. It's my first real vacation (i.e., not visiting extended family) in about two years, and a much-needed respite.

Blogging will be spotty until mid-June. I'm trying to round up a few guest articles, and will post some pictures now and then as time and internet access allow.

In the meantime, keep looking up!