Tuesday, September 30, 2008

Hubble's problem is more like a flat tire than a wreck

A mechanic fixes a flat tire
An astronaut repairs Hubble's broken Side A Data Science Formatter
Image Credit: North Carolina Department of Transportation

My blood pressure went up today when I read headlines saying "Hubble telescope fails" or "Is the Broken Hubble Telescope Worth Saving?" These headlines make it sounds like a horrible calamity has befallen Hubble.

As I said yesterday, Hubble is not dead. Having a problem, yes, but far from "failed" or beyond repair. All that has happened is that Hubble has lost a part necessary for sending its scientific data (pictures) back to Earth. There is a backup that scientists are booting up (this takes a few weeks), and the whole unit (main plus backup) can probably be replaced in a couple of hours by the astronauts when the next Hubble repair mission goes.

I think a good analogy involves car trouble. Suppose you are driving across the west Texas desert, you're about 10 miles from an exit, and you get a flat tire. You have to stop the car, get out the spare, and put the spare on the car. Then you drive to the exit, go to a repair shop, and get the flat patched. Now, you have four good tires, still have a spare, and you're safe to hit the road (which is good, because it's 100 miles to the next town). This is the situation we think Hubble is in. It can't do science right now until the spare electronics are going, but once they are up, Hubble will be good to go until the repair mission shows up in a few months. After that, the broken unit will be replaced, and Hubble will be good to go for another 5-15 years.

Now, suppose you're in the car with a flat tire, and you find that you forgot to keep your spare inflated, so it's flat, too. What happens? You get a little angry, call AAA, and wait for the tow truck, which takes you to the exit, where you get the tire fixed and the spare inflated, and then you're good to go. Yes, you lost some time waiting for the tow truck, but otherwise you're no worse for the wear. If Hubble's spare data electronics package doesn't work, this is the situation Hubble will be in. It will have to wait for the repair mission before it can take data again, but we still think that the repairs would fix everything, and Hubble is again good to go for 5-15 years.

Now suppose you are driving, and you don't have a flat at the exit, so you fill up with gas in the town and start down the road again. Suddenly, 100 miles from anywhere, you get a flat. Now you are in trouble. If your spare is inflated, you can keep going, but you're down to no spare tire. And, if your spare is deflated, you are in serious trouble. That's the situation we would have been in if Hubble's electronics had continued to work until just after the repair mission. Thankfully we aren't there!

Now, think of worst-case scenarios. You're driving across west Texas and have a wreck, or the transmission falls out of the car, or the car catches fire. That's bad. Your car is toast, and now only worth the value of the scrap metal, which isn't much. Hubble is not in this situation. Like a car with a flat tire, Hubble can't operate properly, but it isn't a worthless hunk of scrap metal.

So, I think it completely overstates the problem to say that Hubble has failed, and it gives people the impression that the telescope is just a pile of scrap metal. As I said, that's not the right impression. Part of Hubble, a repairable part that has a spare already on board, quite working. But we think the spare will work. And, if the spare doesn't work, the space shuttle is coming to the rescue soon. We just need to (a) figure out what happened, and (b) train the astronauts how to fix it. Worst case scenario: we have to wait three months for any more pretty pictures from Hubble. And, while it may be annoying, it's no worse than waiting for that tow truck. At least we know it's not far away and it's coming, and we'll all be back in business soon.

Monday, September 29, 2008

Hubble trouble

In the last hour or so, news has come out that the Hubble Telescope stopped sending data, forcing NASA to delay its upcoming repair mission for several months.

Hubble is not dead. What died was the main antenna for sending science data back to Earth. There is a spare, and NASA is trying to get it working. And there are other antennas used for the housekeeping tasks that keep Hubble pointed and the batteries charged and so on. However, the spare is not yet up and running (this could take a few days or weeks), and there are no other spares, so NASA needs to decide if it wants to repair the dead antenna. That means getting parts and procedures ready, when none exist. And it means more training for the astronauts, who rehearse the repairs over and over again. There's just no way to be ready for that in two weeks. So the launch is off until early 2009.

My initial feeling is that we were quite lucky. If the antenna can be repaired, then we'll have both the main antenna and the spare working after the servicing mission. But if the antenna hadn't failed until, say, November, then we'd be down to just the spare for the remainder of Hubble's life. So the timing of the failure was pretty good.

In all likelihood, Hubble will be working again (using its spare science antenna) soon, and it will be virtually brand new after the repair mission next year. It's worth the wait!

Now, if I could just be as positive about my bank...

Friday, September 26, 2008

Mothballs In Space!

Detection of naphthalene in the Interstellar Medium
Image Credit: Gabriel PĂ©rez, Multimedia Service/
IAC

Although we refer to outer space as a "vacuum," it isn't really empty. There are atoms and gas molecules flying around, although they are rare (generally just a few atoms per cubic centimeter, whereas our atmosphere has about 2 x 1019, or 200 million trillion atoms per cubic centimeter). The gas and molecules we find between stars is called the interstellar medium, or ISM.

Around the sun, the ISM is pretty thin, and mostly made of individual atoms. But around the stellar nurseries where new stars are being formed, the ISM gets pretty thick. Not as thick as Earth's atmosphere, but thick enough that atoms are likely to bond together to make molecules. Simple molecules, like carbon monoxide (one carbon atom and one oxygen atom) , have been known for many years. But recently, astronomers have begun to find more and more complex molecules, including alcohol and even amino acids (the building blocks of proteins, and so important ingredients for life)!

This morning, the Astrophysical Institute of the Canary Islands and McDonald Observatory announced the discovery of naphthalene, one of the most complex molecules ever seen in space, in the ISM in a star-forming region in the constellation Perseus.

Since so many complex molecules have been found in the ISM, it may not seem exceptionally newsworthy to add another to the list. But, like amino acids, naphthalene is a molecule that is useful for life. The presence of naphthalene and amino acids in space means that many of the complex chemicals needed for life are actually quite common in the Universe. Any new planets forming around the baby stars in this part of the sky will have a nice supply of organic molecules incorporated into them. Given just the right conditions, perhaps life could even form. As the astronomers involved in this work are continuing to look for even more complex organic molecules, don't be surprised to hear of similar discoveries in the coming years.

When I heard the announcement of the discovery of naphthalene, the first thing I thought of was mothballs. Naphthalene is the main active ingredients in mothballs. And that got me to thinking, maybe the naphthalene is not native to the ISM. Maybe aliens in Perseus have seen the movie "Starship Troopers" and, not knowing it was just a movie, have decided to protect themselves with giant floating mothballs. Or, perhaps, Starship Troopers is real, and we'd better get to work building our own space-borne mothballs. Or maybe not.

Thursday, September 25, 2008

Texas state science standards

Texas is revising its state science curriculum as part of its periodic reconsideration of educational standards. Yesterday, there seemed to be a small victory for science education, as the Texas Education Agency (which makes official recommendations for curriculum revision) recommended changes that remove ideas "based upon purported forces outside of nature" from the science curriculum. While the language being removed sounds innocuous (I mean, we should be teaching students how to evaluate the "strengths and weaknesses" of hypotheses), this language is coded language for the teaching of Young Earth Creationism (or parts thereof) in the science classroom.

But this victory is likely only fleeting. The revised standards must gain approval by a 15-member state education board, seven of whose members have publically supported the language that is being removed; two of the remaining are undecided. And, last year the state education board showed it was unafraid to completely ignore carefully-constructed education standards when they threw out years of studies on revising an English curriculum and passed a new curriculum that most of the board had only seen for a few hours, and hadn't had time to even read. The same could easily happen (and, alas, is likely to happen) with science standards.

Why should you be concerned about Texas education standards? Texas and California are the nation's two largest markets for text books, so most text books, even those sold in other states, are edited to conform to the standards of those states. In other words, we push your state around when it comes to education, like it or not. Whether it be science, English, or history, chances are good that students in your state will be affected by decisions that Texas and California make regarding curriculum.

So, here's to one minor victory for science education.

Mythbusters: The Early Years.

Dr Bunsen Honeydew and Beaker

Some mornings, it's nice to start off with a laugh. And that's what the above image gave me this morning.

I also had two high school science teachers who reminded me very much of these two characters. Those same teachers do not remind me of the Mythbusters in the least.

Tuesday, September 23, 2008

Ready to go fix Hubble

Image Credit: NASA

The above scene is one you'll never see again: two space shuttles on the launch pad, ready to launch. The closer shuttle is Atlantis, which is scheduled to launch on October 10 on the final mission to upgrade and repair the Hubble Space Telescope. The background shuttle is Endeavour, which is being readied to be able to launch on an emergency rescue mission, should it be needed. (If Atlantis is damaged during launch, like Columbia was, Endeavour will launch to pick up the astronauts and bring them home.) If it is not needed, Endeavour will move to the other launch pad and prepare to launch on a mission to the space station.

These days, it's easy to forget how much of a failure Hubble seemed to be when it was first launched. Because of its mis-shapen primary mirror, it was no better than a ground-based telescope, and at several times the price! But, thanks to astronauts, engineers, and the foresight to make Hubble easily repairable, Hubble has become one of the most successful astronomical instruments ever. And, if this mission succeeds, Hubble should be able to operate for at least another 5 years, perhaps much longer! We all owe the astronauts from all of the Hubble missions a giant debt of gratitude.

And, speaking of the possibility of astronaut rescues, anyone ever remember seeing drawings of the astronaut rescue ball? When I was a kid and just getting interested in space (the space shuttle program was just starting then), I remember seeing drawings of this thing (usually with some sort of orangish-pink coloring) everywhere. It's probably a good thing that this particular idea was dropped.

Monday, September 22, 2008

Participating in Science 2.0

A few months ago, I read an article from Scientific American on a new concept in science, known as Science 2.0.

In an overly-diluted nutshell, the idea of "Science 2.0" is to make use of new tools on the internet, such as wikis and blogs and the like, to allow a freer exchange of information in science. Scientists can write about their experiences, experiments, and results on-the-fly, in addition to (or instead of) waiting and boiling it down into a single journal article that can take years to produce. The result: more shared information (scientists believe that free access to information is almost always good), which results in better science.

My first reaction to this was, "fat chance." A small but very serious problem that we don't talk about very much is academic dishonesty. There are some people out there who are not above taking other people's ideas or data and running with them, trying to publish a paper before the originator can. In some cases this may be almost justifiable, such as if the original author is taking an inordinately long time (though there may be good reason!) to work on an interesting problem. But I've seen several cases where things were pretty blatant -- a grad student mentioned her/his work to a more senior person at another institution, and within a month, that senior person announced the "discovery" of that very thing. Or Hubble data, which only the proposing scientist has access to for the first year, somehow finds its way into the hands of a competitor, who does an analysis that clearly takes six months and submits a paper the very day that the data become public, while the proposer is left feeling "scooped." It happens, though rarely.

So, I asked myself, why would I want to share the details of my work with the world, especially if I am getting an interesting result and don't want to get scooped? Especially when I'm at a critical time in my career, trying to make a name for myself. So, at the time, it seemed to me like an idea doomed to fail.

This weekend, I spent most of the weekend working on a wiki for an instrument at McDonald Observatory. For those who don't know, a wiki is just a series of web pages that any reader (or selected readers) can freely edit. Wikipedia is one example. Wikis have their problems; Wikipedia pages are routinely filled with wrong information, deleted by vandals, or even changed to include intentional misinformation. Such changes can be undone, once they are caught, but, in the meantime, who knows what innocent reader was lead astray. There are ways around this. Pages can be set so they can only be edited by select people, automated programs can be written to look for vandalism, and so on.

Wikis have two great advantages: they are easy to edit (people who don't know web coding like HTML can just type away), and they can be changed by multiple people, so if someone has useful information to add, they can do so.

And this is what, in my opinion, makes wikis great for writing instruction manuals for astronomical observations. At any observatory, instruments are constantly changing due to upgrades and repairs and modifications, but instrument manuals (often written by people who no longer work on that instrument) are slow to change. And, the people who know the true capabilities of an instrument often are not the builders of the instrument, but the users of the instrument. So, why not have a page that a sleep-deprived astronomer can edit at four in the morning to describe how they fixed some weird problem that cropped up?

So, anyway, this weekend I was taking an existing written instrument manual and wikifying it, at the same time adding in my own personal opinions and updates. And then it hit me -- that is what Science 2.0 should be -- an online version of walking down the hall and asking a collaborator, "How do you do this?" Or, "what do you make of this weird object I found?" Or, "I hear that the telescope doesn't point right, do you know anything about this?"

And I went back and re-read the Scientific American Article on Science 2.0, and I realized that my thoughts were very similar to what the authors were conveying. I hadn't read and considered the story deeply enough to appreciate the point that their concept of "Science 2.0" is much more than just sharing results or some sort of world-wide research team, especially since it is the sharing of detailed ideas and results is where a lot of the problems with academic dishonesty can come in. Their idea of Science 2.0 is essentially making an online version of the typical research department, where scientists can come together and talk through problems and work on forming ideas and learning what techniques do and don't work. And then we can all go off by ourselves to work on our detailed research using what we learned. And by increasing the size of the community beyond the bounds of the typical University campus, we increase the overall brain pool on which we can draw that crucial piece of knowledge that was keeping us from finishing a project.

And the more I thought about it, the more I realized that astronomy is already evolving rapidly in the direction of this "Science 2.0" concept. We have online wikis, discussion forums, software user groups, blogs, publishing sites, and so on. Most of us have just never tried to lump this into a single, pretentious-sounding term like "Astronomy 2.0". Instead, the rapid evolution of online tools and online community has just become part of our science. And, while the problems of academic dishonesty are still present, they are no worse than they have been.

So, I was wrong. "Science 2.0" not only is a good idea, but an existing, functioning, and constantly-evolving tool of modern astronomy. A tool that I was participating in, without even knowing it.

Sorry for the technical glitches, and, update your bookmarks!

Over the weekend, I made some (hopefully mostly transparent) changes to the main website and old blog site after a weird file system meltdown at my (former) website hosting company. For some reason I was only able to edit backup versions of files, which doesn't help when trying to correct errors in HTML code that were sending some blog visitors to horrid error pages. And the "guaranteed 24-hour response" help team hadn't responded to two week's worth of queries. So, I quickly moved to a new hosting company, where hopefully things will work better. But if you received error messages this weekend, I apologize. That should be behind us now.

For those of you who haven't done so, please update your bookmarks to the "new" blog web address: blog.professorastronomy.com. You may also need to update your RSS feeds (if this post isn't in your news aggregator, you need to fix it). Use the links on the right side of the page. The old pages are both hosted here and on the old blog, and will exist there indefinitely, so any links you have will still work.

We apologize for the inconvenience.

Thursday, September 18, 2008

We underestimated the power of the Dark Side

A Segway, Galaxy Segue 1, and Marla Geha
It's Segue 1, not Segway 1.
Image Credits (clockwise, starting top left): Segway, Inc., Yale, M. Geha, SDSS

The smallest galaxies that we know about are incredibly wimpy. Take the newly-discovered Segue 1 (named after the SEGUE survey, not the personal transportation sensation that has revolutionized travel, at least for tourists in certain large cities). Segue 1 was discovered last year by astronomer Vasily Belokurov and collaborators. It is faint. Darn faint. Adding up all the light from all the stars in Segue 1, the whole galaxy is about 350 times brighter than the sun. Think about that. The Milky Way is about 10 billion times brighter than the sun. But Segue 1 is only 350 times brighter than the sun. The whole friggin' galaxy is just three hundred times brighter than the sun. There are open star clusters, loose collections of stars, in the Milky Way brighter than that. The lower left picture above shows a picture of Segue 1. Can you see a faint galaxy there? I can't. But it is indeed real, as we'll find out.

But light isn't everything. We have known for some time that a lot of small galaxies seem to be made of a lot of dark matter. We know this from measuring the speed with which stars move through a galaxy; this speed is closely related to how strong the pull of gravity is, and the pull of gravity is directly related to how much matter there is. If we measure the speed of stars, we can get how much matter is there.

A team of astronomers headed by one of my grad school classmates, Marla Geha (that's her picture up above), went to the Keck Observatory and measured how fast the stars in the direction of Segue 1 were moving. First, they found that most of the stars in that direction are not related to Segue 1. This was an important finding. The lower-right picture above is really just a map of the stars that Marla and her collaborators found to be true members of Segue 1. With that picture, you can see that Segue 1 kinda looks like a typical dwarf galaxy -- scattered stars, concentrated toward the middle, oval-shaped, and faint (which we already new).

This finding also disproved one theory that Segue 1 was a clump of stars that had been ripped out of the Sagittarius Dwarf Galaxy, a moderate-sized galaxy that our big Milky Way is currently shredding apart. Streams of stars ripped from the Sagittarius dwarf galaxy cross the entire sky. We know they come from the Sagittarius Dwarf because they all move in the same direction in the dwarf galaxy's orbit, like marathon runners that are falling behind the main pack. The stars in Segue 1 are moving in a different direction, so we now know for certain that this is its own galaxy.

When Marla Geha's team measured the speed of the stars in Segue 1, they found that the stars were moving about with speeds of around 4 kilometers per second (2.5 miles per second). This is very pokey by astronomy terms; stars in big galaxies move 50 times faster than this. It's even slower than the star speeds in globular star clusters, tight conglomerations of hundreds of thousands of stars that are part of the Milky Way galaxy. So, some thought that Segue 1 must just be a wimpy globular cluster.

However, Geha's team next determined how much matter was needed to make enough gravity to move the stars around at these speeds. The answer was about 450,000 times the mass of the sun. This is still not very much matter, by astronomical standards. But look more closely at the numbers. The galaxy is only 350 times brighter than the sun, but is 450,000 times more massive than the sun!

Astronomers like to use a measure called the "mass-to-light" ratio. This is simply how much matter there is in a group of stars divided by the total amount of light from the group of stars. By definition, the sun has a mass-to-light ratio of 1: it has the mass of one sun divided by the light of one sun. (Even I can do that math.) Let's look at globular clusters. The globular cluster Omega Centauri is about 1.2 million times brighter than the sun, and its mass (measured from the speed at which its stars are moving due to gravity) is about 2.5 million times the mass of the sun. So, Omega Centauri's mass-to-light ratio is 2.5 million / 1.2 million = about 2. In other words, Omega Centauri has about two Sun's worth of matter for every single Sun's worth of light it puts out. That's to be expected, because globular clusters are mainly made out of lots of stars that are a little bit less massive than the sun but a lot fainter. (A star with 80% the mass of the sun puts out only about 1/4th the light of the sun.) Most star clusters and bright galaxies have mass-to-light ratios between 1 and 10; these ratios can be explained by different mixtures of normal stars and gas.

Okay, so let's move way out and look at clusters of galaxies. These clusters can contain tens or hundreds of galaxies the size of the Milky Way. All of the light in a big cluster of galaxies adds up to about 1 trillion times that of the sun. But when we measure the amount of matter due to gravity, we get one hundred trillion times the mass of the sun. So the mass-to-light ratio of a cluster of galaxies is 100 trillion / 1 trillion = 100. That's ten times bigger than we can explain by adding up all of the mass of stars and dust and gas and other "normal" matter. Some other type of matter that we can't see has to be there -- we call this matter "dark" matter. We think that about 80% of the matter in the Universe is dark matter and about 20% is normal matter (a note for you purists out there, I'm excluding dark energy here.

Now, back to Segue 1. It has the light of 350 times that of the sun, but a mass 450 thousand times the mass of the sun. So, its mass-to-light ratio is 450 thousand / 350 = 1,285. That's 13 times larger than clusters of galaxies and 130 times larger than ordinary matter can explain! In other words, this galaxy is about 98% dark matter, and only 2% normal matter! Segue 1 is a galaxy that has truly gone over to the dark side.

We think that most of the Universe started off with a pretty standard mix of 80% dark matter and 20% normal matter. How did Segue 1 lose so much of its normal matter?

We think there are many reasons Segue 1 lost its ordinary matter, but probably the most important reason is something called "supernova blowout." When galaxies form stars, they make a wide range of stars. A bit of star formation will get you a lot of tiny red dwarf stars, several sun-like stars, and a few whopping big stars. You'll also have a lot of leftover gas that didn't go into making stars. In a normal galaxy, like the Milky Way, that gas is used over the ensuing billions of years to continually make new stars.

Big stars live fast and furious lives, ending in tremendous supernova explosions. In these explosions, huge blast waves are sent into space. These blast waves sweep up a lot of the gas and accelerate it outwards at tremendous speeds, perhaps tens or hundreds of kilometers per second.

Now remember, the stars in Segue 1 move about due to gravity at a measly 4 kilometers a second. If they were moving much faster, gravity wouldn't be able to hold onto them. So, imagine what happens to the poor galaxy when, shortly after spending a lot of effort to make a few big stars, those stars explode. The blast waves accelerate all of Segue 1's gas to speeds ten times faster than gravity can hold on to. Whoosh! The gas is gone forever. No more star formation. And, since Segue 1 hadn't had much time to make a lot of stars yet, most of its normal matter is in the form of gas. All gone, forever.

But dark matter isn't affected by blast waves, because dark matter is only affected by gravity. And blast waves, while they have a lot of energy, don't have much gravity. So the dark matter stays behind in Segue 1. And, voila! You have a galaxy with a ton of dark matter, and almost no ordinary matter. No one knew that a galaxy could have this little ordinary matter. But there it is!

By the time you get to big galaxies, like the Milky Way, the supernova blast waves are moving slower than the galaxy's escape speed, so the Milky Way can hold onto all of its gas and make stars constantly for billions of years. So the Milky Way still has a pretty normal ratio of normal and dark matter. And, for galaxies with masses in between that of Segue 1 and the Milky Way, the supernova blast waves are strong enough to push the gas around quite a bit, but not get rid of it all together. When we look at these galaxies, we see that they tend to make stars in little bursts. They'll make some stars, the supernovae go off and push the gas around, causing the star formation to stop. But, over time, gravity can pull the gas back in and make another burst of stars, more supernovae happen, and the gas gets pushed out again, only to eventually be brought back in to make yet more stars.

In short, Segue 1 is a really cool galaxy. Marla Geha's team has made some extraordinary discoveries about Segue 1, showing us how close this galaxy is to not existing at all. Congrats!

Wednesday, September 17, 2008

Please help with hurricane disaster relief

As you well know, Hurricane Ike ravaged the Texas coast five days ago. While clean-up is well underway, conditions are actually getting worse for many people in the Houston and Galveston area. People are quickly running through their savings, just trying to survive. Refugees are returning home to find now power and few supplies. Government relief is around, but we all know how well that works. And the devastation is quite sobering. Check out the pictures from the Austin American-Statesman of the damage and recovery. There is also a lot of information, pictures and video from the Houston Chronicle.

The people affected by Ike could really use your help. The best way to help is by donating money to a respectable charity (I prefer the American Red Cross due to their proven track record). Although donations of food and clothing and building supplies can be useful, money is the most useful.

Proposal season

For many observational astronomers, the next few weeks are one of the busiest times of the year. Several observatories, including the National Optical Astronomy Observatory (they run Kitt Peak, Gemini on Mauna Kea, and some Chilean telescopes, and pay for some nights at other facilities), McDonald Observatory, Steward Observatory, Lick Observatory and Keck Observatory (to name just a few), all have deadlines for telescope proposals between now and the first week of October.

Telescope proposals are when astronomers put forward our ideas for what we would like to look at with a telescope over the next 4-6 months. We have to write a fairly short but detailed document explaining what science we want to do, how the particular telescope we are asking to use can do that science, why no other telescope is better, how much time we need to do the science, and why we are the best astronomer(s) to do that science. All of that in just 4-6 pages!

Most telescopes will get requests for 2 or 3 times more telescope time than is actually available. It's a lot worse for some telescopes, like the Keck telescopes or the Hubble telescopes, where astronomers tend to ask for 5 to 10 times more time than possible. It is up to the Time Allocation Committee, or TAC, to decide which proposals get time. This task starts with a ranking of the best science, but it also includes intense discussion of feasibility of projects and how to resolve conflicts (perhaps two astronomers want to look at the same target for the same reason, or perhaps everybody wants time in April and nobody wants time in June). Being a TAC member is a lot like being a referee in sports. You do the best you can; often you do an excellent job, sometimes you have to make close calls without all the information, and sometimes you screw up. In the end, everyone complains about the TACs and how they messed up. But few people are willing to serve on TACs, because you have to read through dozens of proposals that are often poorly written or missing crucial information, and then you have to sit in a small room for 1 or two days arguing with other TAC members over proposals. It's a thankless task. So, I will be focusing in the next few weeks on writing several proposals that try to give the TAC what they need to fall in love with my science. It's no fun, but it's part of the job.

Tuesday, September 16, 2008

Get ready for the International Year of Astronomy 2009!

video
Video credit: International Year of Astronomy 2009, IAU and UNESCO
Click here for additional versions of the video and additional credits.

There's a touch of fall in the air here in Austin, a none-too-subtle reminder that another year is starting to wane. Looming on the horizon is one of the biggest coordinated astronomy events ever, the International Year of Astronomy 2009 (IYA 2009). The goals of the IYA 2009 are "to help the citizens of the world rediscover their place in the Universe through the day- and night-time sky, and thereby engage a personal sense of wonder and discovery. " That's a pretty lofty goal, and we need your help to make it happen.

Next year, there will be numerous astronomy events around the world and throughout the year, and I and my fellow astronomers will be advertising these events in the coming months. But now is the time to get connected and organized; this is difficult in a world that contains over 6 billion people and only about 20,000 professional astronomers. So, I'm asking for your help. How can you contribute?

  • If you teach science at any school level, or if you know someone who teaches science: The IYA 2009 is preparing many special events for all educational levels. In the USA, we are further working on ensuring that these events meet state and federal science education standards (so teachers don't need to feel guilty about talking about astronomy in school). Many of these programs are still in the planning stages, and not too much information is available (to our chagrin). But if you are a teacher, please get connected (see below) and stay in touch for details! Also, if you are a teacher, even if you don't teach science, please encourage your colleagues throughout your district to get involved. Even if you aren't a teacher, chances are you know several, especially if you have kids in school. If you know a teacher, please encourage them to learn about the IYA 2009, to get connected, and to use the IYA 2009 in their curriculum! Now is the time to get networked! (It's been a little disappointing how few teachers know about the IYA 2009...)
  • If you are an amateur astronomer: Chances are good you've heard about the IYA 2009. But if you haven't, get connected (see below). We'll need you and your clubs to be outreach, especially to areas where professional astronomers are few and far between. Special observing nights are being planned, and we'd like you to pull out your telescopes and let members of the public take a peak! Also, we encourage you to encourage your friends and colleagues to get connected as well.
  • If you are a professional astronomer: get your department involved, look into AAS-sponsored activities, stay in touch, and HELP GET PEOPLE NETWORKED! There's no excuse for any professional astronomer not to be working their tail off for IYA 2009. None whatsoever. Professional astronomers not helping out deserve scorn and derision and tenure revocation and a pox upon them and their students. Plus, when you need to fill out that EPO section on your next NSF or NASA grant, IYA 2009 may give you some ideas....
  • If you are a leader of a community or organization: Get connected (again, see below)! In addition to the science, the IYA 2009 provides opportunities for outreach to underprivileged parts of the country and the globe. The IYA 2009 is a chance to introduce people of all ages to science and technology education.
  • If you don't fit into these categories: Get connected! If you are reading this blog, you clearly have some interest in science and astronomy. And, chances are pretty darn good that you know other people who fit one of the above categories -- help us by getting them connected, too! Finally, when IYA 2009 activities and opportunities come to your community, you can help us by convincing family and friends to attend and learn about the Universe in which we live!
So, how do you get connected?
  • First, see the IYA 2009 web sites and read about all of the activities that are being planned. The primary websites are: astronomy2009.us (for people in the United States) and astronomy2009.org (for everyone throughout the world). Each country also has their own National Node; visit their website or get in touch with that office (see astronomy2009.org for contact information).
  • Stay connected. Bookmark the main websites and any specific activities, and check them regularly. Read astronomy blogs for updates. If you are involved in social networking, most major networks have IYA 2009 links, such as Facebook, MySpace, and Twitter.
  • Donate money. Alas, none of this is free. The US National Node lists specific areas where financial aid is needed, such as the Galileoscope program, which intends to provide low- and no-cost telescope kits to classrooms across the globe.
  • Volunteer! The US Node website is keeping track of ways you can volunteer to help. Whether you only want to help for an hour at a star party, or if you want to get deeply involved, your help is needed.

I'll be blogging much more about the IYA 2009 in the future. For now, Get Connected!

Monday, September 15, 2008

Trying to reason with hurricane season

Hurricane Ike
Hurricane Ike covers Cuba in this picture from the International Space Station
Image Credit: NASA

This weekend, Hurricane Ike barreled into the Gulf Coast of Texas, causing extensive damage to Houston, Beaumont, and Galveston. Here in Austin, just 160 miles from the landfall point, we had winds of about 10-15 miles per hour, and no rain (there were some sprinkles on my car windshield at one point, but not enough to even need the wipers).

I did, however, have an unpleasant run-in with FEMA. I was driving my recycling downtown when I passed a FEMA convoy. The wind was a little gusty at the moment (not TOO bad, the official wind gusts were all under 25 miles per hour), and a couple of the FEMA trucks towing trailers started getting blown all over the place, taking up a good lane-and-a-half. I thought, "Great. I survived the non-disaster, and FEMA still will manage to find a way to kill me."

What surprised me the most, though, was local panic in places on Friday night. It had been clear since Thursday afternoon that Austin was not going to see much of the storm. So, although I had food at home, I decided to stop in the supermarket to get a frozen pizza and some chicken for the grill. The store was a zoo. Bread was flying off of the shelves, as was water. There was plenty of milk. People were irritable and in a foul mood. When I checked out, the clerk told me that several of the local gas stations had run out of gas (I didn't bother to try and verify this, since I had plenty of gas anyway).

I'll admit, I was a bit surprised. There are three full-time weather stations on cable TV (the Weather Channel and two local variants). The National Hurricane Center has a website with detailed and well-presented updates every few hours. Many local people have weather radios. There are at least a jillion local and national weather websites. And, of course, there are normal weather reports on TV and radio. All were saying we were in for some light to moderate winds, a chance of rain, and that was it. Yet people were panicking! So much for living in the Information Age.

I don't mean to belittle the need for caution. Certainly, the people of Houston, Beaumont and Galveston needed to take precautions and get to safety, and for good reason. (It amazes me that some people didn't take appropriate precautions.) But there was no lack of information telling Austinites that the worst we would have is some rain and some wind, maybe a power outage or two if a tree blew over.

I'm sure there are interesting studies in psychology, herd mentality, information processing, and education in there somewhere. But, that's not my field. Time to go back to looking up.

To the people of the Texas Coast, my heart and thoughts are with you.

To the rest of you, please consider donating money to relief efforts, such as the American Red Cross. The storm is gone, but relief efforts take years. Just ask the people of New Orleans.

Wednesday, September 10, 2008

It's the end of the world as we know it (but I feel fine)

Today, the world's largest particle accelerator started. Contrary to fears, the world hasn't been swallowed by a black hole or changed into a lump of strange particles yet. Of course, the accelerator is just in the shakedown phase; the main experiments will start later. But, as I've said before, I'm not worried in the slightest.

What are my thoughts on this?

  • Hats off to the Europeans, who forked over the money to see this project through. We gave up on ours years ago.
  • "The God Particle" is a dumb moniker for what the Large Hadron Collider is looking for. For most people, the term "God particle" brings up images of its properties that are far from reality. Besides, "Higgs boson" is more fun to say.
  • The LHC is not recreating the Big Bang. It will recreate conditions that were similar to those present shortly after the Big Bang, but we aren't going to be creating baby universes in Europe.
  • There is ZERO (0) chance that the LHC will destroy the Earth.
  • If you doubt me on that last point, check http://hasthelargehadroncolliderdestroyedtheworldyet.com for up-to-the-minute updates.
  • If you'd like to read/watch all about a mad scientist making a mini black hole that threatens the Earth, look into The Krone Experiment. It was written by an astronomer. A darn good astronomer, too, though you can feel free to debate his literary talents. Note that the book is classified as science fiction.
  • One part of The Krone Experiment reminds me of a favorite Carnac the Magnificent segment, when "sis boom bah" is revealed to describe the sound an exploding sheep makes.

Monday, September 08, 2008

Space Shuttle At Risk From Space Junk?

Space junk circles the Earth
Image Credit: NASA

The graphic above shows the space debris that NASA follows around the Earth. Most of this is just junk, pieces of spacecraft and satellites that have disintegrated (or that have been purposefully destroyed, including by the United States). The stuff closest to the Earth is gradually slowed by the tenuous outer reaches of our atmosphere, and it falls back to Earth and burns up. A lot of the meteors you see at night are actually human junk following back to Earth. But the higher stuff can last for decades or hundreds of years, because the atmosphere gets even thinner the higher you go.

Space debris is dangerous stuff. All the debris in the picture above is large enough that we can detect it with radar. But there is a lot more debris that is quite small -- flakes of metal or chips of paint or pieces of bolts and nuts and rivets -- and we can't detect it from the Earth. This junk can be moving at very high speeds relative to other satellites (hundreds or thousands of miles per hour), so if it hits a satellite, it can cause a lot of damage. And if that other satellite happens to be a space shuttle or space station, a single, undetected screw could puncture a pressure hull, exposing the astronauts to the vacuum of space, likely killing them.

For every space shuttle flight, NASA calculates the risk that the shuttle will be catastrophically lost due to space debris. As long as that risk is less than 1-in-200, then the launch can go forward. If the chance is higher than 1-in-200, then the flight is reviewed.

A news story about the upcoming Hubble Telescope repair mission announced that the chance that the shuttle Atlantis could be lost to space debris is 1-in-185, or too high for NASA regulations. So, NASA is going to have to review the risk and see if it is too dangerous for our astronauts.

Now, something in that risk doesn't quite add up to me. The mission lasts 11 days, and it has a 0.5% chance of being destroyed by space debris. If those odds are constant for any satellite in that orbit, then the Hubble Space Telescope (launched in 1990) has had a 95% chance of being destroyed by space debris over its lifetime. But obviously it hasn't been destroyed (knock on wood). So, it seems likely that the odds of space debris destruction are too high.

There are problems with my analysis. Hubble is smaller than the space shuttle, so that reduces its likelihood of being hit. The Hubble may be capable of surviving hits that would puncture the space shuttle. And the likelihood of debris impact may be going up, as both the U.S. and China have recently practiced shooting down satellites, which created a lot of new debris, raising the chances of a hit.

Space debris is an important concern for any satellite, whether manned or not. We need to work to ameliorate the problem, by means such as building satellites that can be de-orbited and by not destroying satellites for military purposes. However, the space shuttle has larger safety concerns than space debris. It is good and right for NASA to be concerned and alert about space debris, but it would be a little overkill to cancel a mission over a 1-in-185 worry, when the shuttles have roughly a 1-in-70 chance of other fatal mishaps. Let's go fix Hubble!

Friday, September 05, 2008

I lied

Looks like I lied when I said I'd be talking more about what we found. My collaborators want it kept under wraps for now. So, all I can say is, we found something interesting, but we aren't sure it is what we were looking for.

Breaking News: We found one!

We found a variable white dwarf in the Kepler field! Our European collaborators found it, and we obtained confirmation data here in Texas. There's still more follow-up needed, but we got our needle in the haystack. I'm amazed, frankly.

Why I Went to the Mountains, Part 3

Variations in the brightness of a white dwarf
Image Credit: K. Williams/T. Jones/McDonald Observatory

Over the past couple of days, I've slowly been telling the story of my observing run. I hope you'll forgive the length, but I thought it needed some background. Anyway, in my first post I described the Kepler mission, and in the second post, I described asteroseismology and how Kepler may be a useful tool for exploring the interior of stars.

So, enough background. Now for my story. I study white dwarfs, the remains of stars that have completed their life cycles. For most of a star's life, it shines by nuclear fusion. First it fuses hydrogen into helium, and, toward the end, it fuses helium into carbon and oxygen. For most stars, that's it, as their gravity isn't strong enough to do any further nuclear reactions. The star's outer layers puff off in a planetary nebula, laying bare the hot ashes of the dead star's nuclear furnace. This we call a white dwarf, because it is white hot, and because it is tiny (the mass of the sun squeezed into a ball the size of the Earth).

There are many things we don't understand about white dwarfs. For example, while we know that they are mostly made of carbon and oxygen, we don't know how much of each is present. We also don't know how well mixed these elements are in the star. White dwarfs tend to have atmospheres of hydrogen or helium (or, in rare cases, carbon), but we don't know how thick these atmospheres are, or if the thickness varies from star to star. To answer these and other mysteries about white dwarfs, we'd like to be able to probe the interior of these stars. Only we have to do it from dozens of light-years away.

White dwarfs don't make any of their own energy, they simply radiate away the heat they gained back when their parent star was still alive and happily fusing elements. So, over hundreds of millions of years, the white-hot white dwarf will slowly cool off, just like a hot poker withdrawn from a blacksmith's fire will cool from white to orange to red. And, in a specific range of temperatures (about 19,000-21,000 degrees Fahrenheit for white dwarfs with hydrogen atmospheres), the atmospheres become unstable and start to slosh around. That sloshing makes sound waves that penetrate the star, so we can do asteroseismology!

The plot at the top of this post shows the variations in the light from a white dwarf due to this sloshing. Where the atmosphere piles up, it gets hotter, which causes it to glow more brightly. Where the atmosphere is thinning out, it gets cooler and fainter. So, we can "watch" the sloshing of the star by measuring its brightness.

Astronomers have been using this sloshing (which we give the more elegant name of pulsations) to study the interiors of white dwarfs for 25 years. But, like with the sun, our data will become far better and far more useful if we can use a satellite to stare at the same star for years at a time. And that's just what Kepler aims to do!

So, all we have to do is find a pulsating white dwarf in the field of stars that Kepler will be looking at. And that's easier said than done. The Kepler field is full of stars, about 12 million of them! And our best estimates are that there are 2 or 3 pulsating white dwarfs in the Kepler field. Those aren't good odds. But the Kepler people have put a lot of work into cataloging all of those 12 million stars, and our collaborators around the world have used detailed selection criteria to pick out the best candidates. So, our European collaborators have been looking at these stars at their telescopes in the Canary Islands, and I've been sitting in the fog trying to help out from here. Now we just need to cross our fingers and hope to find that needle in the haystack.

Wednesday, September 03, 2008

Why I Went to the Mountains (Part 2)

The sun rings like a bell
Image Credit: NOAO / NSO

Yesterday I blogged about the Kepler Mission and how it will be looking for Earth-like planets around sun-like stars. But, as I said, Kepler can do more than find planets. It can look at any star and return precision data on exactly how bright that star is as a function of time.

Many stars vary in brightness for many reasons. Our own sun varies its brightness over a period of about a month (the length of time it takes the sun to rotate), as sunspots come into view, rotate across the sun, move out of view behind the sun, and then rotate into view again. The sun also slowly changes brightness over its entire 11 year sunspot cycle. And, sometimes the sun flares, producing extra light from a magnetic storm for a matter of a few seconds or minutes. Other stars also show changes in brightness due to rotation or due to flares and other activity, and Kepler will watch several stars for these variations.

Perhaps the most interesting variations in the sun's brightness, though, take place on five-minute time scales. These variations are the "ringing" of the sun due to sound waves moving around the sun. Because these sound waves can penetrate down into the sun, we can use them to probe the interior of the sun , just like geologists can use seismic waves from earthquakes to study the interior of the Earth. (The picture at the top of this post is a cartoon of sound waves penetrating the sun.) The use of these sound waves is called helioseismology.

If you want to study the interior of the sun using sound waves, you have to be constantly watching the sun. Helioseismologists, the astronomers studying the interior of the sun from these sound waves, have set up a collection of solar telescopes around the Earth (called GONG) to watch the sun as much as possible. But the biggest breakthroughs have come from satellites like SOHO, which watch the sun 24/7. Through a careful study of the tiny variations in the sun's brightness from studies like GONG and SOHO, helioseismologists have been able to confirm many theories about the structure of the sun.

Other stars also change their brightness due to sound waves, just like the sun. Although we can't study them in the same detail as the sun, we can still measure the variations. And, just like the sun, we learn more if we can watch stars for as long as possible. So, a satellite like Kepler is perfect for trying to do seismology of other stars (called asteroseismology).

Tomorrow, I'll talk about the type of asteroseismology my collaborators and I are trying to do with Kepler, and why I need McDonald Observatory now, when we'll have a satellite next year!

Woohoo!

Finally, I'm getting decent-quality data. I only had to wait 5 nights.

Finally, a clear night

Sunset at McDonald Observatory

For the first time since my arrival here last Thursday, I was able to see sunset. I took this picture (actually a montage of two pictures) this evening. You can see the crepuscular rays (the sun rays) emanating from the horizon, the moon, and the planet Venus (the "star" just to the left of the weather mast; click on the image to get the larger view). Venus is just emerging into the evening sky, and will slowly rise and dominate the western evening sky for the next several months. (Venus is also one of the most commonly reported UFOs, and we'll see a definite increase in UFO sightings in the next few months.)

Alas, we are not observing yet. One last cloud enveloped the mountain right after I took this picture, and while it is gone, everything is wet with condensation. It all has to be dry before we can observe! Things are drying; with a little luck, I'll be working within a half hour.

I've had some bad luck this year at McDonald. I've been observing a total of 13 nights this year (not counting tonight), and I've only gotten about 1 1/3 nights of useful data. That's just barely over 10%, which is a lousy batting average.

Tuesday, September 02, 2008

Why I Went to the Mountains (Part 1)

The Kepler Mission
Image Credit: Jon Lomberg / NASA

I went to the mountains because I wished to observe deliberately, to front only the essential facts of astronomy, to see if I could not learn what the stars had to teach. (Okay, I'll stop channeling my inner Thoreau.) But what would drive a person to travel 400 miles to sit on a mountain top in the fog and rain and thunder, drinking copious quantities of coffee, and forgo most sleep for a week?

The answer is different every time. But my current observing run is a nice, straightforward project.

Our project originates with NASA's upcoming Kepler Mission. Kepler is a satellite that will be launched next spring; it's primary purpose is to look for Earth-sized planets around other stars.

There are many ways to find planets around other stars. To date, most of the planets that have been found are by the Doppler Effect. The gravity of a planet pulls on its parent star, causing it to wobble a little bit as the planet orbits around. This method is best at finding big planets, because the bigger a planet is, the stronger its gravity, and the more its parent star wobbles. It just isn't possible with current technology to detect the pull of an Earth-sized planet on a sun-sized star.

Another way to find planets is to look for the fading of a star when the planet passes between us and the star. This event, called a transit, requires pretty special geometry to see, so from Earth we can see transits in only about 1% of solar systems. Big planets, like Jupiter, will block 1% of the light from their parent stars. This is pretty easy to see -- people have even seen planet transits with telescopes in their backyards!

But seeing small planets, like the Earth, is a tall order. If we were to look for an Earth-like planet around another star, we'd have to be able to detect a one-ten thousandth drop in the light of a star, and that drop would only happen once a year, and would last only part of a day. And, to make it harder, we don't know which star to look at or when to look!

That's where the Kepler mission comes in. Kepler will stare at 100,000 stars for three and a half years, looking for tiny dips in light that occur at least twice (and preferably three times) at precise intervals -- the signature of an orbiting planet. It's a tall order, but Kepler should be up to the task.

Alas, I'm not looking for planets. (I should be, these days people seem just to want to hire astronomers who look for planets.) But there is other science, besides planets, that Kepler can do, because it will be watching stars for tiny changes in brightnesses for over three years! Any science that involves watching stars change brightnesses can benefit from Kepler. And that's where my work comes in.

Tomorrow, I'll explain how changes in the brightnesses of a certain type of star can tell us a lot about that star, and how that ties in with both Kepler and my nights at the telescope.

Walking around in a fog

Since Thursday evening, I've been at McDonald Observatory in west Texas. And, since Thursday, it has been raining, foggy, cloudy, and generally miserable. Not much optical astronomy can be done in fog, so I've had to find other pursuits to occupy my time.

Some of my time was spent finishing revisions on a paper I've submitted for publication in one of our professional journals. This afternoon I put the final touches on my edits and sent it in to the Astrophysical Journal. Now I have to wait for a few weeks for the peer reviewer to look at the paper, make yet more suggestions, and return it to me. I've been working on these particular revisions for a few months, so it is nice to send the paper back out.

Some more of my time has been spent working on revisions to the format of this blog. I write my articles through Blogger, and they have some neat new modules (like the blog roll, better syndication, and some other cool stuff that I need to figure out how to work). I still need to set up forwarding on the old blog and do some site redesign on my main web site. But late nights are good for that sort of thing.

As for astronomical observing, all is not lost. Despite the night starting off with rain and fog, tonight has dried out fairly well, and there are holes in the clouds. So, I have the telescope pointed, and I'm waiting for one of those holes to cross my targets. Such is the life of an astronomer in bad weather.