Friday, June 29, 2007

More preparations

Having managed to take a class to McDonald Observatory and return them safely to Austin, I now am planning to go back again next week. This time, instead of students, I'll be helping to coordinate a continuing education experience for fifteen middle- and high-school teachers from across the nation. I helped out somewhat with this same program last year (see blog entries for July 13-21, 2006; this year I'm contributing even a little more.

This year's program will be led by Kyle Fricke, a newer employee of McDonald Observatory. It's his first program as a coordinator, so he's a bit nervous. But planning is going well, and I think things will run pretty smoothly. In the meantime, we're putting the finishing touches on plans and materials. It should be a lot of fun!

Wednesday, June 27, 2007

An explosion of interest

99 years ago this Saturday, on June 30, 1908, some widely scattered residents near the Tunguska River of Siberia reported seeing and/or hearing a series of flashes and booms. Seismographs across Europe detected a magnitude 5.0 earthquake in Siberia. Atmospheric pressure gauges in Britain picked up a series of pressure disturbances, and the night skies glowed for several days.

Not until 1921 did anybody discover more about what happened. An expedition to the area found a region nearly 30 miles across with trees that were scorched and knocked over, each tree pointing toward the center of that region. But otherwise the region appeared unscathed. What happened?

Many ideas have been proposed as to the cause of the "Tunguska Event," including some very wild ideas (including UFO crashes and "mad scientist" Nikola Tesla's Death Ray), but over time the vast majority of scientists have come to believe that the Tunguska Event was either a small asteroid or comet that exploded at around 30,000 feet above the Siberian forest. The force of the explosion was about 15 megatons of TNT, or a thousand times the power of the atomic bomb dropped on Hiroshima in World War II. Yet other than some dusty particles that seem to come from outer space, no trace of the meteor has been discovered.

This may change by the 100th anniversary of the event. An Italian research team has announced that they suspect a lake near the center of the damaged trees to be a crater formed by a large piece of the original meteor. This lake has been explored before, but seemed to be old due to the amount of mud at its bottom. The problem is, there are no good maps of the region from before the Tunguska Event, so we don't really know if the lake is new or old.

The Italian team of researchers claims to find that the shape of the lake bed and jumbled rock underneath it are strong evidence that the lake is really the missing crater, and they intend to go back to search for any meteorites that may be at the bottom of the lake.

It is not necessarily surprising that we haven't found any trace of the asteroid or comet. If it exploded 5 miles in the air with a force of 15 megatons, most if not all of the body could have vaporized in the extreme heat. Also, we now know that many comets and asteroids are more like piles of rubble than solid rocks, so the meteor may have shattered into component pieces. Since 14 years passed between the Tunguska Event and the first expedition, the surviving fragments may have been buried or disguised as normal rocks by being exposed to wind, rain, snow, and other weather.

Finding a piece of the original meteor would be really important. We could learn, for example, if the meteor was from an asteroid or a comet. We could also lay to rest (for the umpteenth time) many of the wild theories of the Tunguska event. And, perhaps most importantly, we can learn what happens when medium- and large-sized rocks hit the Earth, gaining some valuable data that might help protect the Earth should we ever find another meteor on the way.

Time will tell if the lake that so interests the Italians will have more secrets to reveal, or if the encounter between the Earth and a chunk of rock or ice over Siberia in the summer of 1908 will remain a mysterious event.

Saturday, June 23, 2007

"You may wish to consider closing the dome."

Today was my class's fourth night at McDonald Observatory. Most of the students are now on a night schedule, so they barely woke up in time for our 4pm field trip to see the Hobby-Eberly Telescope, the largest telescope in the continental United States. After that field trip, Casey Deen (pictured above) mugged for a few pictures as we prepared the telescopes for the night.

Our night started well, though we did see thunderstorms on the distant horizon. About 1 in the morning, we stopped due to clouds, but we kept the telescope pointed at the sky in case the clouds blew over. After 20 minutes or so, the telephone rang. Professor David Lambert, Director of the McDonald Observatory, was calling from a neighboring telescope. Professor Lambert very calmly and politely said, "You may wish to consider closing the dome." So, I sent the students to close the dome just as the skies opened and it began to rain. And then we all had a good laugh about the very cordial tone of Professor Lambert in the face of impending disaster.

It continued to storm and rain all night, and at 4am, after several games of Scrabble, we called it a night. And so here I sit, writing and trying to stay up just a little longer and keep on the night schedule. So now you know what astronomers do when it rains -- wait up as late as possible to see if it is going to clear off. And, if not, we stay up later just to stay on our schedule.

Friday, June 22, 2007

A night of troubles

Some nights at the telescope make me age prematurely. Tonight has been one of those nights!

My observing class is using two different telescopes during our week here at McDonald Observatory. Tonight we had a new camera put on one telescope (to do different types of science), and we started our second night on the other telescope.

I started the night showing the students how to use the new camera on the larger telescope. Things worked fairly well until we went to look at our first object on the sky, when we discovered that we could not get our object in the camera. After struggling with that for a while, we solved the problem (an important part had not clicked into place).

After this, I went to the other telescope to check on the students there. First, we couldn't get the telescope in focus. The computer that is supposed to help us focus the telescope was claiming that it was adjusting the focus, but really nothing was happening. After that, the telescope lost track of the filter (colored glass we use to study stars and galaxies of different colors) it was using, so we had to do some work to figure out which filter was in place. Then, when we went to look at a galaxy, we couldn't find it. We checked the telescope's pointing by looking at a bright star (which was there). So, we went back to the galaxy, and finally found it -- it was much fainter than we expected.

So, finally, three hours after dark, my students were able to get started on their projects. This is the way things go, sometimes. And hopefully everyone learned a little bit about patience and troubleshooting. And hopefully we won't have to learn these lessons again!

Thursday, June 21, 2007

Doing the tourist thing

As I mentioned yesterday, I have my summer observing class at McDonald Observatory in west Texas for the next week. Since many of the students have not been here before, I am taking the students around to many of the telescopes here at the observatory. Today we visited the 2.7-meter telescope, where astronomer Gary Hill took time to show off his baby, a spectrograph called VIRUS-p.

VIRUS-p is an instrument that is a prototype for a new camera being designed for the Hobby-Eberly Telescope. This camera will take spectroscopic images of over a million galaxies in just a few years of operation, and allow astronomers to map out the universe and, hopefully, understand a little bit about "Dark Energy," the mysterious force that is causing the Universe to expand at ever-increasing speeds.

In order to get information on millions of galaxies in a short amount of time, lots of new technology is being used, so we want to test it before spending 35 million dollars on an unproven concept. And VIRUS-p is working extraordinarily well.

Today we also survived several thunderstorms with a lot of lightning. It's always a little scary to be on top of a mountain during a thunderstorm. Lightning likes to hit the tallest thing around, and when we are in a large metal building on top of a mountain, we're that tallest object! But the thunderstorms passed, and now it is a very clear night for the students to gather data.

Tuesday, June 19, 2007

Road trip!

Yesterday, I drove eight hours from Austin to McDonald Observatory, located in western Texas near the town of Fort Davis. My reason for coming out here is to bring the graduate student class I am teaching to the observatory for a week of time on the telescopes. The class is on their way out today, but I came out last night so that I could learn to use a new camera on one of the telescopes before I try and show the students how to use it.

This should be a lot of fun. I'll have my hands full the first couple of nights, but hopefully after that the students will know how to use each telescope, and will be able to take their own data. Then I'll be able to step back from teaching and just supervise.

Over the coming days, I'll take some pictures to share; hopefully one of them won't be a tangled mass of metal that used to be a telescope.

Friday, June 15, 2007

CSI: Universe --- Who set off that explosion?


Image credit: Jon Morse (University of Colorado) and NASA

In 2004, astronomers reported a possible supernova (the explosion of a dying star) in the galaxy UGC 4904, a barred spiral galaxy about 75 million light-years away. However, the apparent explosion was awfully faint for a supernova, and it faded away too quickly for a supernova. And so, the "transient" (as such events are called) was forgotten.

On the night of October 9, 2006, amateur astronomers in Japan detected another transient in the same galaxy, a transient that was confirmed as a supernova several nights later. Not only that, but the supernova seemed to be coming from the same part of the galaxy as the first transient. What was going on? And just recently, European astronomers were able to do a careful alignment of the images of both events, which confirms that they are coming from the same spot. What's going on?

Very massive stars, those nearly 100 times the mass of the sun, live short and violent lives. These stars live their lives on the brink between gravity holding the star together and the radiation from the nuclear reactions at the star's center ripping the star apart. Sometimes these very massive stars become unstable, and can rapidly lose large amounts of material, many times our sun's mass. As that material flies off in a massive eruption, the star can get significantly brighter -- just like the first transient in UGC 4904. Typically, these stars seem to settle back down after the eruption, just like a little burp can make you feel better after you've eaten too much. And we think (or thought) that these stars would go on to live for another 200,000 years or more.

But the supernova throws that into question. Did the same star that erupted a few years ago then go supernova, meaning it had used up all of its nuclear fuel much faster than astronomers thought?

Maybe, maybe not. Massive stars tend to be born in clusters of stars, with many other very massive stars around. And many of these massive stars have companion stars in tight orbits. Because we don't have pictures of this galaxy taken with the Hubble Telescope, we can't see individual stars in this galaxy, so we can't know if the eruption of the star in 2004 and the explosion of a star in 2006 came from the same star. Based on the coincidence and the close timing, it would make sense that they are related. But maybe this just was two separate stars, and the timing was a coincidence.

If eruptions of material from massive stars often results in a supernova shortly thereafter, we should see this occurrence more often. It's only been in the last decade that astronomers have been diligently searching nearby galaxies for supernovae, so more time is needed before the book can be closed on this case.

But maybe we don't have to look too far away. In the southern hemisphere, the star Eta Carina is a massive star, 120 times the mass of the sun. In 1843, the star temporarily became the brightest star in our sky after the sun, despite being 8000 light-years away. Then the star rapidly became fainter than the human eye can see, and it has slowly gotten a little brighter since. This is thought to be the same type of eruption that was seen in UGC 4904 in 2004. The picture above shows a Hubble Space Telescope picture of Eta Carina -- the star is buried in the middle of two giant, expanding bubbles of material. Those bubbles were probably created in the eruption 160 years ago. So, will Eta Carina go supernova soon? 160 years seems a lot longer than 2 years, but in astronomical terms, they are both almost instantaneous. But maybe we will have to wait 200,000 years to see Eta Carina explode. If Eta Carina were to explode in the next several decades, then we would have to re-think these massive eruptions.

Thursday, June 14, 2007

Farewell to Mr. Wizard

It was with a tinge of sadness that I read in yesterday's newspaper that Don Herbert, a.k.a. Mr. Wizard, died Tuesday at the age of 89. When I was a wee lad, I watched Mr. Wizard's World, a series of short science segments on the Nickelodeon TV channel in the 1980s. I enjoyed watching a bunch of science experiments I could do at home, though I suspect my parents wished I wouldn't try those experiments myself.

At the time I didn't know that Mr. Wizard had been around in the early 1960's, when my parents were kids; back then he also inspired many young people to think about science.

One question that continually arises among scientists is how we can inspire more young children to be interested in science. Back in the 1960s, the Cold War resulted in a large push for science education. These days, people acknowledge that science and scientific research are a vital part of our technological society. But these same people view science as a very esoteric and hard-to-understand subject, something best left to brainiacs or other people.

An interest in science does not mean that it becomes somebody's career, or even their hobby. It just means a desire to learn something about it, a desire to keep up on current events. How much time does the average person spend each day catching up on how their baseball team is doing, or how Paris Hilton is faring in jail? If only a fraction of that time were spent reading up on a bit of science news, that would make many of us happy.

The need for some interest in science is based in our democratic society. Science research costs money, but often doesn't generate money for years down the road, so business is slow to invest in science research. That means government funding is necessary. And government funding is distributed by politicians, who need to keep an eye on what is popular and will give them an edge in the election. If even a small fraction of Americans asked their representatives to increase science funding, you can bet it would be done.

So, how should we inspire interest in science? That is a subject of much debate, and probably requires multiple methods. Press releases on exciting research is one way. Outreach programs to send scientists to schools or to bring field trips to laboratories is another way. And television programming is yet another way. To that end, Mr. Wizard contributed a lot, for which we scientists are grateful.

Tuesday, June 12, 2007

It's quiet

Summer brings a big change to astronomy departments across the nation. During the school year, departments bustle with activity. Students wander the halls in search of classes and homework help, research talks and seminars occur almost every day, and most everybody is around every day.

In the summer, things fall quiet. The students leave, making for a much quieter building (and opening up lots of parking). Seminars go on hiatus. Astronomy meetings are held across the globe, so many researchers and graduate students begin globetrotting. The net result is a very quiet building.

We often joke that summer is the time that all the astronomy gets done. Distractions are gone, and we can sit for weeks without interruption and crank out research paper after research paper. Of course, this isn't exactly true. Yes, most people do get more research time in the summer (because they aren't teaching classes, although since I am teaching a summer course, I don't get this benefit). But, with all of the running around to meetings, family vacations, etc., I think most people find their summers just as distracting as the rest of the year. As for me, I'm happy just to have the easy parking and not having to share the elevator with 20 students riding for only one or two floors. As for the work, it'll get done eventually.

Friday, June 08, 2007

Hubble, here we come!

Tonight, if all goes well, the space shuttle Atlantis will launch on a visit to the International Space Station. Since the last shuttle launch, NASA's suffered through a series of bizarre events, including a tabloid-worthy love triangle, a hail storm resulting in an ugly-looking fuel tank, and a train carrying booster parts that derailed twice on its way across the country. With a successful and safe mission, hopefully NASA can put these odd events behind it.

In even better news (in my humble opinion), NASA also announced a launch date of September 10, 2008, for the next and final Hubble Telescope repair mission. Servicing Mission 4 (which is actually the fifth repair mission -- typical government counting, since Servicing Mission 3 was actually two visits) will install two new cameras, repair one existing camera (hopefully), replace the rechargeable batteries, replace broken gyroscopes, add new pointing sensors, and repair some insulation and other minor damage.

Personally, I question the usefulness of the International Space Station. It's horrendously expensive, and hasn't been able to do the promised science because of budget cutbacks. But we've agreed to build it, and we might as well use it (if we can find useful things to do). And, each passing shuttle launch brings us closer to both the Hubble repair and the end of the space shuttle program.

So, if you haven't watched a shuttle launch in a while, why not take some time to watch? Launch is scheduled for 7:38pm EDT. If you don't have access to cable TV, you can always watch NASA TV online. The launch has to happen in a 10 minute time frame for the shuttle to be able to meet the space station; otherwise, they'll have to try again another day.

Wednesday, June 06, 2007

It's a tough job, but somebody's gotta do it.

I've always had great respect for teachers. My mom has been a professional teacher for much of her life, as have several members of my extended family. And I've always enjoyed learning, so I've appreciated anybody willing to dish out knowledge and wisdom.

I've dabbled on the borders of teaching. Certainly the outreach that I do, such as this blog, or talking to people about astronomy, or helping with workshops all involve some elements of teaching. I also was a teaching assistant many times when I was earning my PhD, helping professors to teach classes (usually by grading homework and leading discussion sections). But I've never formally taught a class.

That is changing this summer, as I am teaching a class for graduate students. And while I knew that it would be a lot of work, it is even more work than I was prepared for. And it is quite a draining experience -- after talking for an hour or more, my voice is shot, I'm tired, and just mentally and physically drained.

So, I am gaining a new appreciation for those who make a career of teaching. And I am also gaining respect for college professors who teach three or four classes per semester. I suppose with a little experience things get easier, but certainly never easy!

Monday, June 04, 2007

Congratulations, Fergal!

Image Credit: McDonald Observatory

Today another graduate student has earned a doctoral degree in astronomy. Today's lucky winner is Fergal Mullally, an Irishman here at the University of Texas. Fergal, like myself, studies white dwarfs, the ashes of stars that have burned all of their nuclear fuel.

Fergal has spent the last several years looking for planets around white dwarfs. Due to complex physics that is not well understood, white dwarfs of very specific temperatures "pulsate," getting brighter and fainter as the atmosphere sloshes around. This sloshing is very steady, however, and is almost as steady as the most accurate atomic clocks on Earth.

If a pulsating white dwarfs has a planet around it, the planet's gravity will pull on the white dwarf, causing it to move in its own small orbit. Our sun slowly moves in such an orbit due to the pull of the planet Jupiter. As the white dwarf moves, sometimes it will be a little closer to us, and sometimes it will be a little further away. The light that it emits will then take either a little shorter or a little longer time to get to us. So, if we see the white dwarf's pulses arriving a little early or a little late, and this happens in a very regular fashion, there might be a planet there!

Fergal's results are very interesting. Most white dwarfs don't show any evidence of a planet, but one is very interesting. Fergal still needs a little more data to tell what's going on. And once he knows, I'll let you know.

So, congratulations, Fergal! Fergal will be leaving Texas this summer to take a job as a postdoctoral researcher at Princeton, helping out with some massive amounts of astronomical pictures they've been taking.

Friday, June 01, 2007

Asking the right question

I was reading a story on CNN.com this afternoon about a new video of the "Loch Ness Monster," when I saw this poll asking if I believe there is a Loch Ness Monster. I didn't like the poll's request for a "yes" or "no" answer, though. My answer would be, yes, I think there is a phenomenon in Loch Ness commonly called the "monster," but no, I don't think it is some exotic creature unknown to science or long thought extinct. In other words, I don't think the question is well-phrased, as it ignores important nuances.

The same is true when people ask me if I believe in UFOs. Yes, I think that people see things in the sky that cannot be identified. But, no, I don't think these are aliens come to visit the Earth.

The phrasing of questions, especially scientific questions, is a very important skill that most people (myself included) don't think about often enough. We like questions that can be answered from a simple choice; we don't like nuances. When we ask our politicians, "Do you support or oppose X," we don't want to listen to qualifications. Sometimes it is because the politician doesn't want to answer the question, but often it is because the question we are asking isn't a fair "yes" or "no" question.

I heard a more scientific version of careful posing of questions in this story on NPR's All Things Considered program yesterday regarding the issue of global warming. NASA Administrator Michael Griffen was quoted as saying that it was arrogant to suppose that we have the right to decide what an "optimal" climate is; in other words, it is arrogant to claim we can answer the question, "Is global warming good or bad?" And I think that, to a degree, Griffen is correct. A warmer or colder climate will benefit some creatures and people to the detriment of other creatures and people. Who is to say which creatures/people should or should not benefit from a certain climate change? But I think the problem is that "Is global warming good or bad or neutral" is not a scientifically valid question; science cannot address these issues.

In the NPR interview, Penn State professor Richard Alley states that the question that has been put to scientists is much more clearly defined: "Are the actions of humanity now, in changing the atmosphere by burning fossil fuels, pushing us in a direction that will hurt us or help us?" After all, asking "Is global warming good or bad" covers up a lot of issues -- people suffering through a winter blizzard would benefit from a few degrees warmer temperature, but people living along the equator or polar bears living on the Arctic ice cap would not benefit from it. It just isn't possible to answer the question "is global warming good or bad" with either "good" or "bad." There are a zillion qualifications. Yet when it comes to the more well-defined question Richard Alley poses, the answer is scientifically clear: human activities are pushing in a direction that will cause humankind more harm than good.

A recurring theme in the science fiction/humor world of "The Hitchhiker's Guide to the Galaxy" is the Ultimate Question of Life, the Universe, and Everything. Since beings from across the Universe always wanted to know the answer, they built a computer to determine the answer. And the answer is, "42." When everyone got mad, the computer pointed out that nobody really knew what the Ultimate Question of Life, the Universe, and Everything actually was.

When we ask questions of science, we need to be careful to fully phrase what we want to know. Science is good at answering specific questions. How long ago was the Big Bang? What gene causes people to have blue eyes? What medicine will cure acute viral nasopharyngitis (the common cold)? Is human action causing global climate change? What will these changes be? These are all fairly well-posed questions. Ask me one of those. And leave "are you for or against immigration reform" to the politicians.