Wednesday, October 31, 2007

Happy Halloween!


Monty, by Jim Meddick, 10/29/2007 (Click to see full version)

Although no astronomer I've met believes in ghosts, that doesn't stop us from having our share of scary stories. After all, when we are observing, we are up all night, quite tired, and walking around in the dark with little or no lighting. While no astronomer has yet been attacked by the Undead, experimented upon by aliens, or had her genes mixed with that of a mutant badger, maybe it is just a matter of time.

I was a graduate student at UC Santa Cruz, and spent many nights at Lick Observatory outside of San Jose, California. Lick Observatory is named after James Lick, who earned a ton of money in real estate during the Gold Rush, and donated the money used to build the observatory that bears his name. Lick himself is buried at the base of the pier of the 36-inch refracting telescope of Lick Observatory.

The refractor where Lick is buried is almost never used for science anymore -- upgrading it for science would destroy a very historical and well-built instrument. The refractor is in a large dome connected by a long, narrow, high-ceiling hallway to a smaller dome, where a modern, 1-meter (40") diameter research telescope is housed. This telescope, the Nickel reflector, is used quite often by many people. I used it many nights -- it is easy to run and works very well. The only problem is that you are alone in this hundred-year-old, cavernous, unlit building where a man has been buried. So it is very spooky. There are tales of the elevator mysteriously going up and down during the night, apparently carrying nobody, scaring the wits out of the poor grad student working at the telescope. To get to the restrooms, the observer has to descend a spiral staircase, pass by that long, creepy hallway connecting the 1-meter to the refractor where Lick is buried, use the facilities, walk past the spooky hallway again, and climb the spiral staircase to the control room.

So, one long, winter's night, I was observing on the one meter telescope. I was especially tired, and the night was long. I took a bathroom break, and it seemed especially spooky that night.

Now, it is little known that James Lick was injured in a carpentry accident, and lost one hand that was replaced by a hook. When I opened the control room door, I found that very hook hanging on the doorknob!

Okay, so that paragraph is a lie. But the rest of the story is true.

I went to use the restroom, and I looked down that long, dark corridor toward the refractor and Lick's Tomb. I thought I saw something move down there, which freaked me out a bit, as I knew I was the only person in the building that night. But I chalked it up to my imagination, and I went on to the facilities.

On my way back, I looked down the hallway again, and I definitely saw something moving. As I stared into the darkness, it was also definitely a human form, and it looked at me and said my name. I nearly fainted! And this story is 100% true (except for the hook bit).

And now, the rest of the story: At this point, I recognized the human form -- it was one of the mountain's resident astronomers, Rem Stone, and a Santa Cruz astronomy professor, Burt Jones. Unbeknownst to me, they were using the refractor telescope that night for one of its few science projects -- taking photographs of star clusters (they were taking pictures of star clusters that the same set-up had looked at decades ago so they can measure how the stars have moved). But, since I didn't know they were there, I was scared out of my wits for a few seconds.

Tuesday, October 30, 2007

Things that go boom in the night

Last night, I took a couple minutes to go out and look for Comet Holmes, the normally-very-faint comet that you can now see with your plain eye. From a parking lot near my place, I could easily see the comet, despite all of the light pollution. So, if you have clear skies, I bet you can see the comet, too. Some charts to help you locate the comet are here. Around 8pm or so, the constellation Cassiopeia is just a bit north of overhead -- it looks like a "W" in the sky. Then look toward the east. The next grouping of stars toward the Eastern Horizon is the constellation Perseus. To me, Perseus looks like the Greek letter pi. Only now, there is an extra star that is just as bright as the brightest stars in Perseus. As I said, I saw it from a well-lit parking lot last night. So, if you go out trick-or-treating tomorrow night, take a long a star chart and try to find the comet!

People in dark skies, away from city lights, can actually see that the comet is not a point, like the stars, but a little fuzzy. The comet is also fairly yellow, in large part because the light coming from it is reflecting the light of our yellow sun. What we are seeing are the dusty remains of some big eruption from the surface of the comet. The dust is slowly expanding away into space, and the dust cloud is currently larger in size than the planet Jupiter! Of course, there is very little dust there, while the planet Jupiter is far more massive than the planet Earth.

Speaking of things splitting up in space, I saw a commercial on TV last night that had an alien spaceship blowing up the Earth (and, on one of the tiny bits of Earth left, a man sits surprised in his pickup truck, which was durable enough to survive the explosion). That got me wondering -- how much energy would it take to blow up a planet? I didn't feel like doing the calculation (it is straightforward, but I can be lazy), but thanks to the magic of Google, I found the answer. It would take about 2 times ten to the 32nd power Joules, or the entire energy output by our sun in about one million seconds (11 and one-half days). For comparison, one second of the sun's energy output could supply all the world's current energy needs for roughly one million years. In other words, if we took all of the Earth's energy production (at the current rate) for one trillion years, stored it up somehow, and turned it into a laser beam, we could disintegrate the Earth. Thankfully, I don't see that happening any time soon.

Friday, October 26, 2007

The October Surprise

Often, the most interesting things in astronomy happen unexpectedly. A few days ago, Comet Holmes was an extremely faint comet invisible to all but the largest amateur telescopes, slowly circling the sun between Mars and Jupiter. Then, in the early hours of Wednesday morning, Henriquez Santana in the Canary Islands discovered that the comet had brightened by a factor of nearly 25,000 -- invisible to the eye, but easily visible in even small binoculars. And, within a day, it had brightened further -- to third magnitude -- visible to the naked eye, even in the glare of the full moon. All-in-all, Comet Holmes is a million times brighter than it was a few days ago.

What happened?

First, remember what a comet is -- comets are a few miles across, a loose, "dirty snowball" of dust and ice loosely packed together. Far from the sun, everything remains frozen, and the comets are very faint, because they are small. When comets come close to the sun, they warm up, the ice starts to melt, and the comet jets gas and dust out into space. The gas emits light like a neon lamp, and the dust reflects sunlight, so we can see the comet's typical head and tail from the Earth.

Because comets are so loosely packed, they can split into multiple pieces, shed large chunks, and even completely disintegrate. Usually this happens when the comet is close to the sun (and feeling stressed by the build-up of pressure from melting ice and gas) or when the comet is very near a planet or the sun, when gravity helps to rip it apart. But, sometimes, the comet just spontaneously breaks apart or sheds a lot of matter. This seems to be what happened with Comet Holmes.

Comet Holmes had a similar outburst over 100 years ago, in 1892. So, for some reason, this comet seems to be prone to either breaking apart or suddenly shedding dust. Perhaps, if we can better understand this comet, we can understand how comets formed, and how we might protect ourselves if a comet were ever to be discovered coming this way.

Do you want to see Comet Holmes? First, you need to live in the Northern Hemisphere. For now, you can still see it with your unaided eye, though binoculars will help, especially if you live in a city. The comet is in the constellation Perseus, which is up all night this time of year. Star charts like those found at Sky & Telescope are probably necessary, especially if you don't know where Perseus is. (Don't use the moon in the pictures -- the moon moves a lot from night to night). Probably the comet will be visible to the naked eye at least a few more days. Good luck!

Wednesday, October 24, 2007

Wildfires and statistics

It is awful to watch the disaster unfolding in southern California, where wildfires are threatening major cities and nearly 1 million people have been forced from their homes. It is my sincere hope that the fires quickly abate, and that people are able to work together for a fast recovery. (And, at the same time, maybe we should re-double our efforts to speed the recovery of the Gulf Coast, which is still sputtering along after the devastation from hurricanes Katrina and Rita.)

Unfortunately, disasters such as wildfires, strong hurricanes, heat waves will continue to strike new areas as climate change due to global warming continues. Due to global warming, some areas of the world will feel improved weather, such as warmer winters in Canada, increased rain in currently try climates, and other such "nice" things. But, weather will worsen in other areas. Normally wet areas will dry out, and in the transition, wildfires will occur.

So, then, are the California wildfires a direct cause of global warming? I don't know, and anyone who claims to know is probably wrong. The reason is that extreme weather, such as the droughts in southern California over the last year, or strong hurricanes in the Atlantic, have occurred before. Even without global warming, such weather would eventually occur again. Climate change theory predicts that extreme weather will become more common, but it cannot tell us whether a specific event was due to global warming.

Let's look at another example. Suppose I were a casino owner with a craps table (a dice game). In a normal craps game, getting "snake eyes" (or a "one" on each of the two dice) is typically a very bad roll for the gambler (and therefore good for the casino owner). With a fair set of dice, snake eyes will appear on average once every 36 rolls of the dice. It could be that snake eyes will come up twice in a row, or even a hundred times in a row, but if I were to roll the dice thousands of times, on average snake eyes would appear once in every 36 rolls.

Now, suppose I am a bit of a cheat, and I replace the dice with loaded dice (dice with tiny weights in them) such that snake eyes appear once every 24 rolls. It's still rare enough that most people wouldn't notice the change, but, over time, the casino would win much more often than in a fair game. Now, suppose a gambler rolls snake eyes. Is this one set of snake eyes due to the loaded dice? Maybe, maybe not. It may be that, with fair dice, she would have rolled snake eyes anyway. Then she rolls snake eyes on a second roll. Again, is it due to the loaded dice?

Again, we could not be sure. Such is the funny nature of statistics. With completely fair dice, it is possible to roll snake eyes four times in a row --- it's a one-in-a-million chance, but remember that millions of people play craps each year! The next gambler may roll 100 times with loaded dice and not see snake eyes (a 1 in 100 chance with my loaded dice). It would only be after many, many games that we could figure out whether or not the dice were fair or loaded.

So, it is the same way with strange weather. It may be that, even in the absence of global warming, Katrina and Rita would have both hit the Gulf Coast in the same year, and that a drought would hit California this year. It is only over time that we can build up enough statistics to say that more storms and droughts are occurring. Likewise, a year without a strong hurricane doesn't mean that the danger has passed (ask the folks in Central America whose homes were destroyed by hurricane Felix last month). Even a string of lucky years doesn't mean the danger hasn't increased.

What's the take-home point of my ramblings? It is that you cannot say whether one specific weather event is due to global warming or not. What we can say is that, if we do not change the human impact on the environment, strong hurricanes and severe droughts will become more common in places that rarely had trouble before.

Tuesday, October 23, 2007

Building the space station

If the weather cooperates, in one hour the space shuttle Discovery will launch for yet another construction mission to the International Space Station (anyone else remember when President Reagan announced that it would be called Space Station Freedom?)

This shuttle mission will finally (nine years after the first part was launched!) move the space station toward fulfilling it's stated mission: science. The Harmony module, which will be added during this flight, is where science laboratories from the European Space Agency and from Japan will be attached, with the European Lab being launched on the next shuttle flight in December. The new module also adds three more sleeping berths, allowing up to six astronauts, cosmonauts, taikonauts, and whoever else to stay on the space station.

The space station is a great engineering feat, and the astronauts who have risked their lives to build it have my deepest respect. But it has been a long, expensive, and painful process, and I find myself wondering if the science that will come out of the space station will be worth the cost. I really don't know. And, I don't know how long the ISS will be operational -- the Soviet/Russian Mir Space Station operated for 15 years, and it was getting harrowing toward the end.

At any rate, my best wishes go with the men and women onboard Discovery, and I wish them a safe and productive journey.

Monday, October 22, 2007

How big is the moon?

This week (Thursday), another full moon will rise as the sun sets. And, since the nights are getting dark so early now, the moon will rise pretty high in the sky before the typical person goes to sleep. So, this month is an ideal time (as is any winter month), to explore the moon illusion.

The moon illusion is quite simple to notice. When the moon is rising, it looks really big. When the moon is high in the sky, it looks smaller. But if you use some measurement technique (say, comparing the moon to the size of your thumb held at arm's length), you'll find that the moon is really the same size at both places! This also means that the moon illusion is not due to the atmosphere, but to something in our heads.

The reason for the moon illusion is controversial; several theories are discussed in the Wikipedia article on the subject. And, every so often, I hear of a new hypothesis explaining the moon illusion. To some degree, all of the ideas make sense, but I am not a psychiatrist or medical expert, and so I don't have the expertise I would need to weigh in with a learned opinion. But, since our distant ancestors rarely had to worry about trouble coming from the skies (a lion is far more dangerous to us than a hawk or an eagle), it makes sense to me that our brains cannot properly interpret sizes of objects in the sky.

The thing that does amaze me is how many people insist that the moon is actually bigger when it is near the horizon than when it is overhead. As I said, you can easily measure the size of the moon by using your own fingertips held at arms' length. But most people never bother to try. In some ways it is similar to the story about the famous Greek philosopher Aristotle, who claimed that men had more teeth than women. However, if he'd ever bothered to count teeth, he would have seen that the numbers are the same. (Of course, there is probably more to the story than that.)

Friday, October 19, 2007

Even smart scientists can be stupid

A few days ago, Nobel-prize winning biologist James Watson made some pretty racist comments (which he has since tried to retract). Watson is one of the co-discoverers of the structure of DNA, and deserves the accolades he's received for that achievement. But his remarks are inexcusable and non-scientific.

Like any human, we scientists are full of our own biases and opinions. When we are working on our science, we must set those biases aside (as much as is possible), but I've never met any scientists who have been able to rid themselves of biases and opinions. It's part of being human, and it's also a driving force behind the advancement of science. If we didn't hold opinions, fight for them, and feel driven to search for evidence supporting our ideas (or against someone else's ideas), then science would go nowhere.

Often, too, as scientists succeed and become secure in our jobs, we tend to explore a little more of the fringes of science. I've seen physicists exploring ESP, an astronomer who thinks he's discovered evidence of extraterrestrial civilizations, and other such things. I think it is okay to explores such issues if one feels like they can shed new light on a topic, but typically the evidence is no stronger than supposition and tying together facts that don't really mesh. As one friend once said to me, "There's a little bit of crackpot in each of us."

None of this excuses Watson's remarks, and hopefully outbursts like his can show that racism continues to linger in places where many would claim it has been abolished. However, it is important to stress that his remarks are those of Watson, the human, not Watson, the Nobel-winning scientist.

Thursday, October 18, 2007

Webcast tomorrow on exploding stars (supernovae)

Friday, October 19th, at 7pm Central Daylight Time, there will be a webcast titled "Exploding Stars in an Accelerating Universe." This webcast will be given by Craig Wheeler, a professor of astronomy here at the University of Texas. Professor Wheeler is also the current president of the American Astronomical Society, the largest organization of professional astronomers in the United States.

To view the webcast, you need to download a special plugin for your browser. Details on how to view the webcast and about the topic can be found here.

Go, Hubble, Go!

This week, while our big symposium was underway here at Texas, the Hubble Space Telescope was also working on my behalf. This week, over a period of 7 days, Hubble is collecting the data for my approved project. It's about halfway done, and everything seems to be working so far! Although, to be honest, I haven't seen any of the data yet.

Getting pictures from orbiting telescopes is much different from getting pictures here on Earth. On the ground, we astronomers go to a mountain, operate the telescope, put our images on computer disks, and then take them back home.

But space is different. Of course, we can't go to the telescope and control its every move (that would be fun, but rather expensive). But there are other constraints, too. Hubble is not in constant contact with the ground -- we can only get its data when it passes over ground-based radio antennas. As I type this, Hubble is over the South Pacific, east-southeast of Kiribati, so there aren't many radio antennas there. Also, Hubble is constrained to keep within a certain angle of the sun in order to get solar power, so there are only certain times when my object is visible. In between those times, Hubble wanders to other parts of the sky to work on other projects. And, because Hubble has an old computer, all the observations must be planned weeks in advance. Even if I were to have my laptop attached to the radio antenna receiving Hubble data, I would not be able to make changes if there were problems with the data.

So, I have to be patient. My data will be downloaded as time permits, checked for egregious errors, processed through basic steps, and then sent to me. Only then, probably some time in the next week or two, will I know how good or bad my pictures are!

Wednesday, October 17, 2007

The Frank Bash Symposium


Image credit: University of Texas/McDonald Observatory

The last two days saw the third Frank Bash Symposium at the University of Texas, titled "New Horizons in Astronomy." The symposium is unique in astronomy, in that it is organized by, for, and features postdoctoral researchers (astronomers who, like myself, have completed their doctorate degrees but have not yet obtained a permanent professorship). It honors retired astronomer Frank Bash (pictured above), who was director of McDonald Observatory for 14 years, and who has always encouraged young people in science, whether undergraduates, graduate students, or postdocs.

I was one of the organizers of this year's event. I was co-chair of the Scientific Organizing Committee, the committee responsible for selecting the 13 speakers and responsible for getting people to attend the conference. My co-chair, Justyn Maund, probably did 3/4 of the work in this regard, but there was more than enough work to do! I also helped with the Local Organizing Committee, the group that takes care of logistics like finding a room, making sure there is coffee for 100 astronomers, finding accommodations for our speakers, and so on. The chair of that committee, Stuart Barnes, and our primary administrative assistant, Monica Kidd, did a phenomenal job in that regard. Everything went quite smoothly! But I think we are all exhausted after three full days of final preparations and execution of the event.

So, fresh of this experience, I now need to plunge into organizing another conference that will be here in Austin in January. This time I'll be the local organizer, as I'm the only local person in the group.

Friday, October 12, 2007

When to keep or discard a theory

I've been blogging a lot recently about how wonderfully simple science is -- you come up with an idea, make predictions based on the idea, if the predictions hold true, then your new theory lives to fight another day; if the prediction fails, you discard the theory.

But this is a greatly simplified view. If a theory fails, we don't always toss it out, because even wrong theories can be mostly correct, and with a little re-tooling, the theory can be saved. Imagine, for example, that a friend tells you she can identify any type of car based solely on the engine noise, long before she can see the car. So, you go to a spot where you can here cars before seeing them and you test her abilities. She gets the first ten cars right, but for the eleventh car she predicts a Chevy Tahoe truck, and then a Ford F-150 comes into sight.

Is your friend's theory that she can predict the cars wrong? Obviously not completely, because she is 10 for 11, much better than chance. Maybe the Ford needed a new engine, and the owner stuck a Chevy engine in. Maybe those two particular engines are just a little too similar to tell apart. Or, maybe your friend is a very lucky guesser.

In science, there are theories that we know are not the full story. For example, Isaac Newton's Law of Gravitation are a theory of gravity. We use these laws to send space probes to the far corners of the Solar System. You can use Newtonian gravity to predict precisely where the planets will appear in the sky ten thousand years from now. Except for one pesky problem -- the planet Mercury doesn't follow Newtonian gravity exactly. It's very, very close, but not quite right. Does this mean that Newton was all wet, and his theory is complete hogwash? NO!

Newton's Law of Gravity is not completely wrong, but it is incomplete. It took Einstein to realize how Newtonian gravity was incomplete, do to a complex relationship between space, time, and mass. Einstein's Theory of General Relativity makes the necessary corrections, and it has worked in every situation it's ever tested! But if you take Einstein's General Relativity and look hard at the equations for the Moon going around the Earth, they look almost exactly like Newton's gravitational equations. They have to, because Newton's gravity works for the moon!

More yet, we know that Einstein's General Relativity and another major physics theory, quantum mechanics, cannot both be true. One, or both, must be incomplete. This doesn't mean that relativity and quantum mechanics are hogwash -- GPS satellites use relativity to determine your position, and many parts of the satellites' electronics use quantum mechanics to do those relativity calculations. For what we ask the theories to do, they are good enough, though of course we are looking for the full answers.

Today, the Nobel Peace Prize was awarded to Al Gore and to the United Nations' Intergovernmental Panel on Climate Change (IPCC) for their work in alerting the public to the imminent dangers of global warming. Al Gore has worked tirelessly to spread the message; the IPCC is a body trying to put together all the pieces of the science. A number of vocal people are claiming, though, that global warming does not exist. I've already blogged about how, among scientists, the reality of global warming is not debated, though, amazingly, some non-scientists still claim there is a debate. It is true, though, that the climate theories differ on the predictions of exactly what will happen, though all of these theories predict global warming will continue and accelerate. Obviously, these theories are incomplete. But, just because of that, it would be wrong to completely throw climate theory out the window! We joke about how the weathermen never can predict the weather, but they are right quite often (Click here to see how accurate your weatherman has been -- all of the cities I've tried are above 70%). So, like Newton's Law of gravity useful for a lot of things, we clearly know something about weather and the climate and can make good use of that knowledge.

Thursday, October 11, 2007

Radiation everywhere!

This morning, I was reading this news story on a new type of security scanner that is being tested for use in airports. I'm not going to comment on the discussions of privacy issues and airport security. But I'm blogging about it because I noticed a subtle error in the science that is a common misconception in the public. The quote in question states:

The new type of device being tested, called a "millimeter wave" machine, doesn't use radiation, Golden said Wednesday during a demonstration for reporters at the agency's headquarters in Arlington, Va. Instead, it uses electromagnetic waves to create an image based on energy reflected from the body.

The problem is with the word "radiation." When most people hear that word, they think of nuclear bombs, horrible illness, deformities, and other awful things. But, to a scientist, radiation is much, much more.

There are two main types of radiation that most of us experience: particle radiation and electromagnetic radiation. Particle radiation deals with subatomic particles, including protons, electrons, alpha particles (two protons and two neutrons joined together), muons (another subatomic particle), and many other such things. We are constantly being bombarded with most of these, and most are not dangerous in small amounts. Muons from cosmic rays are constantly passing through us; there is nothing we can do to stop these particles, but luckily most do no damage. Alpha particles come from certain types of radioactive decay; our skin easily stops those, and it takes a really high dosage to do harm a person. Electrons can come from radioactive decay, but electron radiation is also used in cathode ray tubes (the heart of a lot of TV sets and computer monitors). Electron radiation can do damage, but, again, you need to be close to the source to be in trouble.

Electromagnetic radiation is also a part of everyday life. We often call it "light." This radiation includes radio waves, microwaves, infrared light, visible light, ultraviolet light, X-rays, and gamma rays. The list above is in terms of energy, from the weakest to the strongest. The dangerous radiation is all high energy -- gamma rays, X-rays, and ultraviolet light. These are energetic enough to damage our cells and our DNA, and so are best avoided. But small doses are okay (like a diagnostic X-ray), and even necessary (UV light is needed by your body to produce some vitamins).

On the other hand, radio waves and microwaves are very weak. So how does your home microwave cook food? The microwaves in there are tuned to specific frequencies (like tuning your radio), and at those frequencies water absorbs microwaves and turns them into heat. So, if you keep pumping those microwaves in to some water, the water will warm up. But if the microwaves aren't at the right frequencies, they'll just pass right through you without doing anything.

So, back to the news article. Note the quote says that the millimeter wave machine doesn't use radiation. WRONG! Millimeter waves are radiation! What the article should say is that the millimeter wave machine doesn't use harmful radiation, like an X-ray machine does. (However, even the X-ray machine uses such a low dose that the person being screened would not be harmed; it is the security people who might be in danger harm's way.)

The point is that radiation is not inherently bad. Radiation is just a physical process. The bad radiation is energetic radiation (X-rays, gamma rays, ultraviolet light, and certain types of particles). So, the next time you hear that something is emitting radiation, don't instantly get worried. Stop and think, is this harmful radiation? And, if not, you can breathe easier.

Wednesday, October 10, 2007

Nobel Week Continues...

Today, the Nobel Prize in Chemistry went to Gerhard Ertl of Germany, who provided insight in to understanding how chemical reactions take place on surfaces. I am not a chemist, nor do I study materials science, so I cannot say much about Ertl's work that was not stated in the various online news stories about the award.

Today is the first day of talks here at the University of Texas by John Mather, last year's winner of the Nobel Prize in Physics. Dr. Mather will be speaking on topics other than his Nobel-winning work, but I'm going to talk a bit about the science that resulted in the Nobel because (a) I almost understand it, and (b) it is an ideal illustration of the way science should work.

The whole story begins with the Big Bang. The Big Bang theory was proposed back in the 1930s to explain the observation that all galaxies in the Universe appear to be moving away from one another. If you run the clock backward far enough, all of those galaxies should have started in the same spot. So, a giant explosion of some sort about 14 billion years ago might explain why all the galaxies appear to be moving away from one another.

This is a nice idea, but to become an accepted theory, an idea has to make testable predictions that pan out. In the late 1940s, the Big Bang theory was developed further, and it made two major predictions. One, it predicted that the universe should be about 75% hydrogen and 25% helium. Two, it predicted that the universe should be glowing in microwaves, and "echo" of the Big Bang still visible today. Both predictions were found to be true! This is why the Big Bang theory is widely held to be correct. Not only did it explain what we already knew, but it made testable predictions that proved true.

Yet another prediction was then made. In order for galaxies, stars, and people to form in only 14 billion years, the Universe had to be slightly lumpy after the Big Bang. Not too lumpy, or everything would collapse into a black hole, and not too smooth, or gravity would not have had time to pull things together. Therefore, predictions were made that the echo of the Big Bang, called the "cosmic microwave background," should show lumpiness at a very small, but detectable level. This level would be one part in one hundred thousand. Such a measurement is hard, but quite possibe -- like trying to determine how many people live in New York City and not be off by more than 75 people, and then repeating the same measurement for forty thousand other cities, all within three years.

So, anyway, the lumpiness was predicted, but had not been seen. John Mather was lead scientist on the project that built a satellite, the COsmic Background Explorer (COBE) to measure the lumpiness. And, they detected the lumpiness, at just the right level that theories predicted! This was an amazing feat, and also another amazing confirmation of the Big Bang theory. Since that time, the WMAP satellite has made even more precise measurements of this lumpiness that have confirmed even more aspects of the theory.

Lots of people (though only a few professional astronomers, who can be counted on the fingers of two hands) claim not to believe in the Big Bang theory. Yet when push comes to shove, the Big Bang theory has made several testable predictions that have been proven true. No other theory can claim that. It is also true that the Big Bang theory is not the whole story -- it cannot explain some details in what we observe. Expanded versions of the Big Bang theory (using things such as "cosmic inflation" and dark energy) do seem to be able to explain these details, but these ideas are still in development and being tested. I think they will be right to some degree, but time will tell. Yet all of these expanded theories include the Big Bang, because the Big Bang theory works. No other theory does.

It's a point I bring up on here many times, because it is crucial to understanding why scientists believe certain theories. An idea is suggested to explain observations. The idea makes predictions. If the predictions are right, the idea will become an accepted theory. If the predictions fail, the idea has to be changed or discarded. And, in the case of the Big Bang theory, it has predicted several things that have since been discovered. And each of those is worthy of a Nobel Prize.

Tuesday, October 09, 2007

And the Nobel Prize in Physics goes to...

Wait, let me find it. It's somewhere on my computer. No, not on the desktop. Hmm, not under My Documents, either. I hope I didn't put it on my data disk; I've got 1000 Gigabytes of data there, and just about anything could be there.

Ah, here we go. This year's Nobel Prize in Physics went to Albert Fert of France and Peter Gruenberg of Germany, who discovered "giant magnetoresistance," or the ability of a tiny change in magnetic field to lead to a big change in electrical resistance in a substance. It may sound esoteric, but this is the effect that has allowed your computer hard drives to become big and cheap over the past ten years.

I am quite happy that the Nobel Prize went to celebrate this effect. Alfred Nobel set up his prizes in part to give an award to those whose science helps humanity. And while 30-gigabyte iPods may not be a huge boon to humanity, the availability of cheap data storage does help society -- by hooking such hard drives up to the internet, large quantities of data can be stored and shared. And if you are travelling on a different continent and need medical attention, the ability of a doctor to access your home medical records may be life-saving, yet your records wouldn't be available if data storage on computers weren't cheaper and more reliable than paper files. Advanced medical equipment like digital X-rays and 3-D MRI machines require huge amounts of data storage space, but lead to ever-improving diagnoses. Likewise, a scientist can travel through the jungle or desert, taking huge quantities of data on the current state of the environment for further analysis back home. Robotic spacecraft can now take millions more pictures than before because there is room to store the data. And on, and on, and on.

So, congratulations to Fert and Gruenberg! We've all benefited from their work.

Monday, October 08, 2007

Time for the (Ig-)Nobel Prizes

I finally finished my telescope proposals last night (a good thing, as they were due at 8am this morning). Hurray!

This week is the week that the Nobel Prizes are awarded. Today the Nobel Prize in Medicine was announced, and tomorrow will be the Nobel Prize in Physics. In an oddity of timing, this week last year's winner of the Nobel Prize in Physics, John Mather, is visiting the University of Texas and our astronomy department as the twelfth recipient of the Antoinette de Vaucouleurs Memorial Medal. de Voucouleurs spent a lifetime studying the properties of galaxies, and the memorial medal honors an astronomer whose life exhibits such dedication to the science.

Also timed to match the awarding of the Nobel Prizes was last week's awarding of the Ig Nobel Prizes, given annually at Harvard by the Annuals of Improbable Research, a magazine dedicated to describing research that either cannot or should not be reproduced. It is (generally) all in good fun, as you might guess when you look at this year's list of winners. This year's awards studied how Viagra helps hamsters overcome jet lag, how bed sheets fold, and the health effects of swallowing swords.

The Ig Nobel Prizes aren't necessarily meant to highlight stupid research; many of the studies are quite serious. But the people publishing the studies usually realize that their work sounds quite humorous when viewed from outside the field, and they often see the humor in it themselves. And, sometimes, you are working on a projects and a fun little sidelight pops up (such as the astronomers who determined that the overall color of the universe is "cosmic latte"). On occasion, barbs are flung at people doing stupid things, but, generally, the Ig Nobels are just a rollickingly good time (at least for fairly nerdy people).

Wednesday, October 03, 2007

Trying to write less

Any of you who have been reading a while, or who peruse the archives, will know that I have a penchant for being a bit wordy, at least when I write. So, as I continue to work on writing proposals to use telescopes, I am finding myself in a bit of a tight spot.

For any proposal, space is limited, or else we'd all ramble on and on and on for pages and pages. Yet the Time Allocation Committee (TAC) has to read each proposal, often with just a couple week's worth of notice. So the last thing the TAC wants are to have 30+ proposals, each 10 or 20 pages long. For this reason, we are limited to two pages of text (one to describe the science, one to describe how we will be using the telescopes), plus a few extra pages with necessary technical data (figures, lists of stars and galaxies, and so on), though these extra pages are not really useful from the standpoint of explaining your project.

Most of the time, I can come pretty close to explaining my science in the allotted space. But sometimes, as is the case with one of my proposals this time, it is really hard. And so I keep scratching my head -- it's not just a matter of what words can I take out, but also what entire topics I have to omit.

We can't get away with commonly-used tricks -- changing font size, margins, etc. Doing so just ticks off the TAC -- it's pretty obvious what you've done, and you are giving them more work.

So, for the next few days, I'll be stretching my brain more. What do I need to say that is crucial for the TAC to understand my proposal? What can I leave out and assume the TAC will know? And what can I get away without discussing?

It is amazing how long it can take to produce just two pages of text!

Monday, October 01, 2007

50 Years in Space


Image Credit: NASA/Asif Siddiqi

Fifty years ago this Thursday (October 4, 1957), the Space Age began when the Soviet Union launched a basketball-sized metal sphere called Sputnik into space. This first ever artificial moon showed that humankind (and, more importantly at the time, the Soviets) possed the technological prowess to explore beyond the tenuous atmosphere of our own planet. Much larger than its technical impact was its psychological and political impact. In less than 12 years, the United States landed the first humans on the moon.

Although I wasn't alive at the time, the Space Race is all the more amazing when I think about what little has changed on Earth in the last 12 years. Although it wasn't huge, the Internet was in use; I already had a website and routinely used email. We are still flying the same space shuttles (although the Russian Soyuz capsules are virtually unchanged for decades -- they are quite reliable).

Still, unlike many, I am not dismayed at the seemingly slow progress of human achievement in space. Robots have explored almost every nook and cranny of the solar system, humans have had a quasi-permanent presence in space, and, perhaps most importantly, satellite technology has transformed human life. Try to imaging life without weather satellites, satellite communications, or GPS systems. Satellite technology is responsible for live video feeds from around the world, and satellite TV and radio are quite popular.

It took humans centuries to master sailing, and at times technology seemed very slow to advance. But, these days we can cruise over (or under) the ocean for months on end with no worries about storms, food, fuel, disease, sea monsters, etc. I think that, in time, humans will learn how to navigate the cosmos (at least our own niche of it). But it may take centuries -- not just the 12 years between the first satellite and the first moon landing. We'll get there.