Au revoir, Agnes

One of the depressing things about summer time as a young astronomer is that it means many of your friends pack up and leave as they advance in their careers. Earlier this summer, two of my fellow postdocs pulled up stakes for greener pastures. And yesterday, we said goodbye to another of our friends, as postdoc Agnes Kim and her husband Ryan left Texas for Milledgeville, Georgia, where Agnes will be a professor in the Chemistry and Physics Department at Georgia College and State University.

Agnes studies white dwarfs, like myself. She works on how white dwarfs might be useful for probing exotic particle physics, like the production of elusive neutrinos, or perhaps even the interaction of dark matter with the normal matter that makes up a white dwarf.

I wish Agnes and Ryan well in their new adventures!

The no-view nova

Image Credit: Contours: ESA/ XMM-Newton/ EPIC (adapted from A. Read et al.), Background: SSS

Most of the time, the stars and galaxies that we astronomers look do not change much, if at all, over a human lifetime. So, our only hurry in looking at a star is to do it before somebody else does. If the weather is bad or the telescope breaks, we can come back another night, or even another year, and there is little lost.

For some astronomical objects, though, time is critical. Supernova explosions, for example, are only visible for a few months or so before fading away from sight. Another, more common explosion, called a nova, only lasts a few nights. Glows from gamma-ray bursts last just a few hours. If one of these events occurs, we need to hop on it fast, or lose it forever.

The problem is, you've got to be looking in the right place at the right time to see one of these. At present, there are only a few small telescopes that take pictures of the entire sky on a regular basis. Such a search produces tremendous amounts of data, and on big telescopes, the biggest cameras can only image about one quarter of one ten thousandth of the entire sky in a single picture. So, much of the sky is not searched by professional astronomers for these time-critical events. Those who do search for these events tend to focus on tiny patches of the sky. Though they'll miss most explosions, they'll still see enough for their science. (The one exception are gamma ray bursts, because the gamma ray detectors in space actually can look at most of the sky in a single picture.)

Typically, this is where amateur astronomers step in. These men and women are often out conducting searches of their own, often using their own eyes and star charts to try and spot something out of place. It may be a comet, or it may be an explosion, or it could be some other event. Amateurs are pretty good at this, and are discovering comets, supernovae and novae all the time. They get a little bit of glory, and a lot of personal pride, out of beating us professionals. And they deserve it.

One of the big prizes is discovering something that will become bright enough to see with the naked eye (i.e., without a telescope or binoculars). Then people around the world will be able to go out and see your discovery, sometimes with your name attached (like Comet Hale-Bopp).

Still, even a small army of amateurs can't catch everything. This was proven in a press release last Friday from the European Space Agency's XMM-Newton X-ray telescope.

The X-ray telescope, like an optical telescope, points at interesting targets and takes pictures. When it moves from one target to another (which takes a long time in space), the cameras are usually turned off. But a group of scientists including Andy Read of the University of Leicester and Richard Saxton of the European Space Agency are running a project where, sometimes, the cameras are kept running as the telescope moves, allowing random objects to drift into the field of view.

Last October, a bright X-ray source popped into the XMM-Newton camera during one of these moves, but, according to catalogs, nothing should have been there. After some quick legwork and a few phone calls to big telescopes, it was determined that the X-rays were coming from a previously unknown nova.

A nova is a distant cousin of a supernova. In a supernova, an entire star explodes during a runaway nuclear explosion. In a nova, the outer layers of a white dwarf star explode like a hydrogen bomb, but the explosion is too weak to blow the entire star apart. As you might guess from the names, a supernova is many times brighter than a nova. But novae are actually more common, because there are a lot of white dwarfs in our galaxy. Several novae are found every year, and every few years, one is bright enough to see with the naked eye. As with bright comets, most novae are found by amateur astronomers, and not by professionals.

The odd thing about the XMM-Newton's discovery, though, is that novae don't make a lot of X-rays early on. So, the nova that XMM-Newton found was actually a few months old, but it had never been reported. So, the XMM-Newton team called up the operators of a robotic all-sky survey called ASAS. They combed through old data, and found that the nova had indeed been picked up by their optical telescopes on June 5, 2007. Not only that, but the nova had gotten bright enough that it would have been easily visible to the naked eye, the brightest nova in over a decade. And yet, not one human knowingly saw it!

How did everyone miss it? Well, the nova was in the constellation Puppis, which is not visible in most of the northern hemisphere (where most amateur astronomers live). And Puppis lies near the Milky Way, so it is full of stars -- only a trained eye would have been able to pick out the new one. But novae are found in Puppis by professional and amateur astronomers quite a bit. We just got unlucky with this one.

Discoveries like this make us wonder how many interesting things happen in the sky on time scales so short that nobody has a chance to see them. For that reason, astronomers are starting to build telescopes that will image the entire sky to very faint limits every few days. The ultimate data will come from the Large Synoptic Survey Telescope or LSST, which will soon be built in Chile. The mirror for this telescope is huge -- 8 meters across, making it one of the largest telescopes in the world. The telescope, in a single picture, can image an area of sky about 50 times the area of the full moon. A single 30 second exposure will be able to see objects about 2 million times fainter than what your eye can see.

Amazingly, the hard part of this project is not the telescope (though it will be one of the most complex mirrors and cameras ever built). The hard part will be the data volume: 30 terabytes of data every night. That's 30,000 gigabytes, or, if you were to put it on a normal DVD, about 6000 DVDs worth of information every single night. For five years. And we want to be able to analyze that data on the fly, so that interesting objects (like novae) can be observed with other instruments at other telescopes as soon as possible. To help with this, money and assistance from Google and the Bill and Melinda Gates Foundation (along with other technologically-oriented companies) are pouring into the project.

The LSST mirror is under construction in Tucson, Arizona, and the construction will soon start in Chile, with hopes of opening this new eye on the Universe in 2014. Hopefully no more novae will slip through the cracks!

Good luck, Seth and Justyn!

Image Credit: McDonald Observatory

This summer, two of our fellow postdoctoral researchers here in the Astronomy Department at the University of Texas at Austin are moving on to bigger and better things. Justyn Maund (left), who studies supernovae, or the explosions of stars, has accepted the Tycho Brahe fellowship at the Dark Cosmology Centre in Copenhagen, Denmark. Seth Redfield (right), who studies both extrasolar planets and the gas between the stars, will soon leave to become a professor of astronomy at Wesleyan University in Connecticut.

Both of these positions are big steps forward in Justyn's and Seth's careers. So, while it is quite sad to be losing two good friends, we are all very happy for them and wish them the best in their careers. And, since astronomy is such a small field, we'll be seeing them again and again at conferences, meetings, and other travels. Best of luck to both of you!

Seeing stars explode in real time

Image Credit: NASA/Swift Science Team/Stefan Immler

When a star ends its life by exploding, it tends to be a while before we see anything on Earth (and this is ignoring the millions of years it takes light to get to Earth). Because we don't know in advance which star in the Universe is going to explode when (as there is no "Upcoming Attractions" posting on the Universe's blog, and psychics continually fail to warn us of these things), we tend to see explosions after the fact. But even if we knew when a star was going to explode, it would be hours after the actual explosion before we saw any light on Earth.

When a massive star nears the end of its life, its core engine (a nuclear fusion reactor) is busily fusing silicon into iron and nickel and cobalt. These elements have absolutely no energy value, so they form a lump of inert ash at the center of the star. When the lump gets big enough, the forces between atoms can no longer counteract gravity, and the core collapses into a neutron star or a black hole. Suddenly, the star finds it has no support in its middle, and the star begins to collapse inward. All of the inward falling material collides, causing a shock wave to go rushing outwards toward the surface at the star at speeds of 10,000 miles or more per second. This shock wave is also probably driven by energy from a stream of subatomic particles called "neutrinos" that are formed by the collapse of the core of the star. When the shock wave reaches the surface of the star, it breaks free in a blinding flash of X-rays and ultraviolet light, as the first energy from the star being ripped apart is released into the empty vacuum of space.

But even though the shock wave is going at these very high speeds, it can take the shock wave a long time to reach the edge of the star. The stars that go supernova can be almost a billion miles in diameter. A shock wave starting at the star's center can take 14 hours to reach the surface of such a star! So, for at least half a day after a star explodes, we on Earth have no clue (in the form of light) that the star has exploded.

Even after the explosion, it often takes days for us to notice anything on Earth. The supernova explosion gets brighter for several days as the shrapnel from the star expands outward, exposing more and more of the bright debris to view. Then the debris starts to cool, and the supernova begins to fade away (though radioactive decay from elements created in the explosion help to keep the star from completely fading away in a matter of days). On Earth, the supernova appears as a point of light that didn't used to be there, and someone has to be looking in the right direction to see it. Because of this, most supernovae are discovered only around the time that they reach their brightest point, which can be days after the explosion.

Yesterday, NASA announced that their Swift X-ray telescope had discovered the break-out flash of a supernova. The telescope was looking at a galaxy when a bright X-ray "flash" was observed. Since part of Swift's mission is to look for flashes of X-rays (most of which come from gamma-ray bursts), the telescope immediately alerts interested astronomers around the world that a flash has gone off. After the alert, many professional telescopes went and looked at the spot of the flash, and were able to catch some of the earliest light ever to come from a supernova explosion. The picture above shows the X-ray picture of the supernova (top) and the optical-light picture of the explosion (bottom).

This research is interesting, because it allows astronomers to explore some of the earliest stages of a supernova. It was also very lucky, because the telescope happened to be looking in the right place at the right time, and the typical galaxy only has a star explode every few decades or so. But is the discovery important (the press release calls this supernova the "Rosetta Stone" for understanding exploding stars)?

Probably this is not going to be a crucial piece of data in understanding supernova explosions. The X-ray flash was expected, and now it has been observed, which does confirm one part of the theory of exploding stars. But it is hard to see that we will learn anything new from a single event. The theory of exploding stars seems to be pretty solid, and what we tend to learn from the earliest stages of a supernova is mostly what the star's outer-most layers looked like, and we already study the outer layers of stars (it's what we see when we look at them). Yes, there are things to be learned, but these are almost certainly just details, not grand over-arching themes. But a cool and lucky find, nonetheless.

This discovery would be great for someone interested in the psychology of astronomical research. Since many different research groups got notification of the X-ray flash, they all scrambled to produce papers and get credit for the discovery. There are grumblings under the surface about the group getting credit in this press release, but there are also good arguments for why they got credit -- I don't know enough to have a well-informed opinion. And the personalities in competing groups are always continually clashing, so there are some, um, colorful opinions floating around. Anyone who claims that scientists are a completely dispassionate people are wrong, and this particular discovery is a great piece of evidence that human psychology plays a large role in science.

Surprising Salaries of Astronomers

Yesterday, this article appeared on CNN.com about five jobs that have surprising salaries. The article stated the following surprising facts:

Surprising salary: $95,740. Though maybe it shouldn't be all that surprising considering a doctorate is the standard level of education and there are only 1,700 astronomers in the U.S.

This article quickly made the rounds among many of us in the astronomy community, because most of us have salaries nowhere near this level. So, where did this figure come from?

I think part of the problem may be in the definition of "astronomer." Most of us would use the term "astronomer" to refer to anyone who is getting paid to do astronomy research. This would therefore include graduate students working on their PhD, postdoctoral researchers (people like me who have a PhD and are doing astronomy research but don't yet have a permanent job), university professors, researchers at NASA or other government-operated laboratories, and many other categories. If you look at a typical salary (say the "median", or the salary level at which half the astronomers make more, and half less), the value is most likely under $50,000, or half of what the article claims. The value that the article quotes is probably close to the average for senior researchers -- tenured professors or senior staff who have been working in the field for decades. Prestigious professors or those at private universities may make more, but there aren't too many of these.

The statement that there are only 1700 astronomers in the US is also too low by a factor of two or three. The American Astronomical Society, our professional organization, has almost 6500 active professional members. This number does include many foreign astronomers, but many U.S. astronomers tend to let their memberships lapse from time to time. So, there are probably at least 7000 astronomers in the U.S. Not a huge amount, but more than the article claims.

I'm not sure where the author got his figures, but his research was either lacking, or he didn't make an effort to understand the field, or he purposefully distorted the numbers for the purpose of interesting copy. Either way, it isn't good journalism. However, I will agree with the article's title, as that salary figure was surprising indeed.

In short, most astronomers agree that you don't go into the science for the money. If you succeed as an astronomer you won't be poor, but you probably won't be in the upper class, either. And, since most of us are paid with tax dollars or tuition dollars, know that we aren't trying to line our wallets at your expense.

Continuing need for astronomy education

Astronomy is one of those fields with a lot of misinformation swirling around. Sometimes I'm forgiving of it, sometimes not. Two cases in point (and one other aggravation that is slightly-off topic, but I'm going to rant about anyway):

(1) I was listening to the radio today, and a commercial for Comcast came on. The commercial was lauding people with genius ideas (such as buying their product), and it referred to Galileo's proving that the "Sun is the center of our galaxy." WRONG!!! The Sun is not the center of our Galaxy. The center of our galaxy is actually a black hole a million times more massive than the sun (not a fun place to be) and about 25,000 light-years away. The Sun is the center of our Solar System (the sun, eight planets, dwarf planets, asteroids, and comets). This sort of mistake is the kind I get upset over, because it is so easy for the ad agency to actually check the facts -- two minutes with Google and Wikipedia would give the right answer. Shame on you!

(2) As I was getting some coffee at Kitt Peak this afternoon, I heard a visitor remark how horribly boring it would be to stare at the same star for his entire life. Well, this isn't what astronomers do. We look at many (if not millions) of stars, or even at other galaxies, which are conglomerations of tens of billions of stars. But this mistake is forgivable -- it is a person with a misunderstanding about what we astronomers do. And that's part of my reason for doing this blog, to try and clear up that understanding. Since my readership is slightly under 6.5 billion people, I obviously have some more work to do to reach everyone.

(3) As I was sleeping this morning, a bunch of teenagers walked past the astronomer's dorm (where there are signs saying "Quiet, Day Sleepers"), and started yelling. Too bad I'm not in Texas, as taking care of that situation would have constituted justifiable homicide. But, instead, I had to seethe on my pillow until the gang walked past, and then I went back to sleep.

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Beatrice Tinsley

Yesterday, I talked about the results of some black hole studies by Dr. Ramesh Narayan, who is visiting the University of Texas Department of Astronomy as the "Beatrice Tinsley Visiting Professor." Since the story of Beatrice Tinsley is not well known outside the astronomy community, I thought I would tell bits and pieces of it here.

Several people have already written Tinsely's biography on the web, and I have nothing new to add. In summary, Tinsley was born in Englang, grew up in New Zealand, married a physicist, came with him to the University of Texas at Dallas. She earned a PhD from the University of Texas at Austin, but was only given an undistinguished research position at UT Dallas. Tinsley performed ground-breaking research (more on that below), but UT Dallas did not give her a professorship. After a long struggle, she left Texas, divorced, and went to Yale in 1975, where she quickly became one of the most distinguished astronomers in the United States. After only six years, she died from cancer. For more details on the life of Tinsley, you can read this brief article from the American Astronomical Society's Committee on the Status of Women in Astronomy, a biography from the the New Zealand Edge, another detailed biography, or you can even a published biography (if you can find it in print).

Tinsely's research was some of the most influential astronomical research of the times. At the time, little was known about the evolution of galaxies -- how did galaxies form, and how did they change over time?

Galaxies, as you may know, are collections of billions of stars bound together by gravity. The Milky Way is a galaxy; the Andromeda Galaxy is a near-twin of the Milky Way located 2 million light-years away. Both galaxies are spiral galaxies. Further away from us, we find some elliptical galaxies, which look like fuzzy blobs and lack beautiful spiral arms. Moreover, elliptical galaxies are distinctly more yellowish than spiral galaxies, which tend to be quite blue. But it used to be quite a mystery what caused these different shapes and colors.

One of Tinsley's most profound insights was that, since galaxies are made out of billions of stars, we can use what we know about the lives of stars to learn about the history of galaxies. We know that bright, blue stars live only for a few million years, while yellow stars like the sun can live ten billion years. So, a galaxy that is currently blue is forming stars now, while yellow galaxies are not.

While most of the above was known or guessed at when Tinsley was working, she put a great effort into calculating not just how galaxies look today, but how they would look over time, depending on how they formed their stars. A galaxy will look different if all of its stars formed in a big flurry of activity 15 billion years ago than if its stars were formed steadily over fifteen billion years, even if the galaxy is not presently making stars. Tinsley calculated models for dozens of different types of galaxies with many different possible histories for star formation -- a tremendous effort in the days before a powerful computer could sit on everyone's desktop.

At the time Tinsley was doing her work, our view of the Universe was rapidly changing. The Big Bang had only recently been proven, and models of stars were only just beginning to tell us how nuclear reactions in stars produced all of the elements in our Universe. The theory behind the life cycles of stars was solidifying into the basic story we believe today. Tinsley was able to take all of this different information and synthesize it in her work. As telescopes allowed us to look at more and more distant galaxies, her work and methods became the central means for understanding the changes that we saw in galaxies as we looked further and further back in time.

People can (and do) discuss at length the positives and negatives of Beatrice Tinsley's life and personality (read the links in the second paragraph), but there is no denying how, in her short career, Tinsley synthesized a tremendous amount of emerging information to become one of the giants of astronomy in the 20th century. And this is why the University of Texas at Austin and the American Astronomical Society both have awards in her name.

Beware, Austin, here we come!

Copyright © 2007 by Sidney Harris

Austin, Texas is about to be invaded. Not by a foreign army, not by aliens, and not by kudzu, but by astronomers. Roughly 2000 astronomers, or nearly one-third of all astronomers in the nation, will be in Austin next week for our 211thmeeting of the American Astronomical Society (the AAS), the nation's largest association of professional astronomers. We have meetings twice a year, and the winter meeting tends to draw the largest crowds.

This also means that next week you can expect to see astronomy in the news almost every day, as astronomers release their newest results to the public. It also means that I have been given tasks of finding several groups of friends places to have working lunches, organizing smaller related meetings, and other such fun tasks. And it means that the people of Austin may be just as likely to overhear discussions about cataclysmic variables and axion detectors as they are to hear about guitar riffs or Longhorn basketball. Like the cartoon above, astronomers tend to live in their own world and have their own jokes and speaking style, so we'll probably stick out.

So, to the city of Austin, I apologize for the invasion. It'll be over in a week. And to the AAS staff, thank you for all of your hard work in arranging a meeting for us. It's a huge task.

I will do my best to try and keep you up to date with the goings-on at the AAS in between all of my hosting duties.

Doing the tourist thing

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

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

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

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

Congratulations, Fergal!

Image Credit: McDonald Observatory

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

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

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

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

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

Is all the romance gone from astronomy?

In this article from CNN, astronomer and planet-hunter Geoff Marcy, nearing the end of a night on the Keck Observatory, laments:

"There are no eyepieces anywhere. In fact, we don't have an eyepiece for the Keck telescope. Some of the romance of astronomy is gone."

Is this true? Is technology removing the "romance" from astronomy?

Most people have the picture of the astronomer as a lone man on a mountain top, looking night after night through an eyepiece on the back of a giant telescope, somehow making measurements of other worlds and other galaxies. There was a time when this was true, but over the past 75 years, astronomy has been transformed by technology. Believe it or not, it was the phtographic plate, invented in the late 1800s, and not computers or digital cameras, that "doomed" the romantic view of astronomy. For, with a photographic plate, astronomers could see fainter than ever before and could take information home to study over long periods of time. By taking information home, more accurate measurements could be made, and more careful analysis performed. Suddenly, an astronomer didn't need months of time to gather all the information he wanted; he could gather a lot of information in a few nights and work on it for months to come.

With computers and digital technology, the science of astronomy has changed even more. Some astronomers don't go to the telescope at all -- some telescopes will take data for the scientist and send it over the internet. There are good points and bad points to this method of observing. I find the quality of my science data isn't as reliable when somebody else takes it, but for some telescopes, like the Hubble Space Telescope, there is no choice!

Modern technology has also opened up new fields that were impossible before. Planets around other stars, Geoff Marcy's main point of study, can only be detected with modern instruments. Yet now, as we find a wide variety of planets around all sorts of stars, our imaginations can run wild with ideas of what we may find. The Hubble Space Telescope has taken amazing pictures of everything from nearby stars and nebulae to the most distant galaxies in the Universe. Due to modern technology, we have discovered black holes a billion times more massive than the sun and watched stars exploding halfway across the Universe.

So, if you consider the "romance" of astronomy to be a lone man on a mountain top struggling to comprehend the Universe, then that romance is lost. But if you, like I, consider the romance of astronomy to be the exotic nature of the Universe around us, then modern technology only serves to open entire new worlds to the power of the human mind and imagination. (Note also that, due to positive changes in society, astronomers are no longer just males; an ever-increasing number of women are contributing to every aspect of the science.)

A News Note: This week, astronomers from around the country have congregated in Honolulu for the summer meeting of the American Astronomical Society. I am not there due to teaching commitments, but you will probably see lots of astronomy news in the coming days as new results are announced!

Back in the desert

On Friday I hopped on a plane (OK, I actually walked on the plane; if I had hopped on, I suspect they would have called security). After hopping/walking on the plane, I traveled to Tucson, Arizona, for a visit. A good friend had a wedding on Saturday, and I thought I would take a few days to visit colleagues at Steward Observatory today before returning home. I probably have several weeks worth of science I could accomplish here, but I'll settle for a day.

The wedding and reception was a lot of fun, though some may question my definition of "fun" if you consider that at least half of the crowd consisted of astronomers from across the nation. Talk would vary from how people/families are doing to evaluations of various astronomy departments to discussion of new science to how we could get various people out on the dance floor, all within a few sentences. But, if we were being geeky, we were all being geeky together. So, congratulations to Jason and Haiyin! And I'll be back to more exciting news from astronomy in a few days.

Is Dark Energy Bad For Astronomy?

Yesterday I became aware of this article by a cosmologist named Simon White (warning: the article is technical). Simon White is a well-known and well-resepcted astronomer, so many of us are mulling over his assertation that the study of "Dark Energy" could be bad to astronomy science. I have not yet read White's monograph carefully the entire way through, but I can sum up a few points.

"Dark Energy" is a name that has stuck to a phenomenon we observe in the universe -- that, as time goes on, the expansion of the universe seems to be speeding up. This is odd, because all the forces we know about in the Universe (light and gravity, mainly), work to slow down the expanding Universe. Gravity tries to act as a brake, but there seems to be a mysterious force still pushing on the accelerator.

The idea of dark energy has captured the imagination of the public, as well as many astronomers and physicists. But understanding dark energy is going to be hard and likely take decades to make much progress. And any such progress will require large investments of money and giant research collaborations.

White's main concerns are that if astronomers focus too much on exploring dark energy, we will be putting all of our eggs in one basket by requiring most of our monetary and scientific resources to go to one project that, while very interesting, may not have that much of an impact on understanding how stars and galaxies work.

The concensus of people that I've talked to is that while White makes some good points, he misses the mark a bit. First, although many large experiments are being developed to study dark energy, we are also finding new sources of money for these experiments (the Department Of Energy is supporting some research, and private individuals are donating money out of interest in dark energy), so large research projects are not eating into the budget as badly as they might.

Another concern of White's is that large collaborations will devour graduate students and postdocs, who will not get recognition for their work. This has been a concern in other large astronomy projects, such as the Sloan Digital Sky Survey, but these young researchers are generally recognized for the science they are doing.

White raises many valid points in his monograph, however. Astronomy has been different from other fields (like particle physics) in many ways, and this cultural difference is, we feel, a positive. It is good for senior and knowledgeable people to point out their concerns so that we remain on our toes and avoid making decisions that might harm the varied and vibrant research of astronomy. But I do not think that the study of Dark Energy is dangerous to the science. The danger would come if the study of Dark Energy were to begin to consume all of our resources. And I just don't see us allowing this to happen in the forseeable future. If anything, studies of Dark Energy allow astronomers to continue to wax poetic on how exotic the universe is, and how much there remains for us humans to understand.

Loss of another astronomy giant

Image credit: Astronomical Society of the Pacific

This morning I received an email from colleagues saying that Bohdan Paczynski (pronounced puh-CHIN-skee), an astronomer at Princeton, died yesterday.

I never met Paczynski, but I am certainly very aware of his large body of work. Paczynski studied gravitational lenses, gamma ray bursts, and other high-energy physics. It is sad to hear of his passing, and a great mind has been lost.

You can read a biography of Paczynski from Wikipedia, the Astronomical Society of the Pacific, or his web page.