Tuesday, January 31, 2006

Peer Pressure

Yesterday I had the pleasure of sending off another paper to be published in one of our esteemed professional journals. This is the second time I have sent this paper in, and I'll probably end up doing a third version before it is finished.

This is not unusual. Most scientific papers go through a process called peer review. Let's say that Professor Jane Q. Astronomer has discovered Star Lucy is made out of diamond, an exciting discovery. After doing the appropriate analysis, Professor Jane writes a paper and sends it to an astronomy journal. The editors at the journal then pick another astronomer who works on similar research to be the peer reviewer. If this astronomer agrees to do the work, he will get Professor Jane's paper and read it through carefully and write comments and concerns on the paper.

Sometimes the comments can be minor, such as "Professor Jane forgot to mention that Star Lucy was first discovered by Lennon, McCartney, Harrison, & Starr (1967). She should mention that." Or "Professor Jane got the coordinates of the star slightly wrong, it appears to be to the northeast by a slight amount."

Other times comments are much more serious, such as "Professor Jane is wrong to say that the star's spectrum shows it is made of diamond; the spectrum is really closer to that of cubic zirconium." Or, on rare occasions, "Professor Jane is aparrently unaware that Professor Billy Bob published this same analysis in a paper three months ago. This paper presents nothing new."

Once comments have been made, the paper and comments are sent back to the author. Professor Jane now should address each of the issues raised by the reviewer, whether it be fixing typos, adding missing information, or more clearly statnig her case. If Professor Jane disagrees with the reviewer on a point, then she must explain why the reviewer is mistaken. When she is finished, the paper is sent back to the same reviewer for his opinion on the revised version.

Often, after this second look, the paper is good enough to be published with a small number of additional, minor revisions. But sometimes these papers can take many iterations, and other times the paper has serious enough flaws that the journal rejects it altogether.

So, here's hoping that this second iteration is good enough for my reviewer!

Monday, January 30, 2006

How to become an astronomer, part 3

Sorry this is delayed a few days; I was working hard late last week on a few things.

So, in the past few days we've talked about the traditional ways to enter a career in astronomy, from things to consider about the career to high school and college preparation. Let's say you've finished these. What's next?

The traditional career path is in academics. Once you have a bachelor's degree, you continue on to graduate school to earn a Ph.D. in astronomy/astrophysics. Then you become a "postdoc," a researcher in a temporary position (usually three years; this is the stage I am at), and finally on to become a faculty member. Easy, right! :)

There are many other career paths these days, though, and often you can wander from one path to another. The government hires many astronomers. The most famous is, of course, NASA, which has many astronomy research facilities across the nation. The astronomers there are typically focused on a certain air- or space-borne observatory or research program. The government also hires astronomers at research laboratories, such as Los Alamos; often these astronomers are working on research programs that can have impact on national defense as well as astronomy, such as supernovae, which are the explosions of giant stars and involve lots of understanding of nuclear physics and nuclear explosions. Finally, the government also runs a few national astronomy centers, such as the National Optical Astronomy Observatory and the National Radio Astronomy Observatory. Jobs at these facilities often involve a little research, a little management of telescopes and facilities, and work on the design and construction of new telescopes.

There are many jobs for people with training in astronomy in private industry. I am not very familiar with these aspects, but I know that jobs range from work on satellites (often with optics systems and guidance systems) to production of research-grade telescopes. So, there are many jobs for the professional astronomer!

Wednesday, January 25, 2006

How to become an astronomer, part 2

So, after yesterday's post, you still want to become an astronomer, eh? Well, if you are in high school or working on your Bachelor's Degree, here are my tips. Certainly this is not the only way to become a professional astronomer, but it is the "classical" route.

In High School:

  • Take as many high-level math and science courses as you can. A standard set of math courses would likely include algebra, geometry, pre-calculus, and calculus. You can always learn calculus at college, so if your school doesn't offer it, that's okay. For science, standard courses include biology, chemistry, and physics. Again, the exact topics are not important, but taking the high-level classes will help you.
  • Take Advanced Placement courses, if your school offers them. Even if these courses are not in science, you may be able to fill part of your college general education requirements.
  • Take writing and speech courses. Writing and public speaking are part of the job of being an astronomer!
  • Keep up on your hobbies. There is more to life than studies. As you advance along the career path, you will need other interests to maintain your sanity. :)

As an undergraduate:

  • Major in Physics! If your school offers an astronomy major, great! You can double-major! But your physics classes are absolutely vital at this point.
  • Get involved in undergrad research. The exact project is not important, but the experience can be. Most astronomy professors are willing to help an undergraduate find an appropriate research project. While these projects are not required to an astronomy career, they do help applications and can help you figure out if you enjoy astronomy research. (A couple of my friends got to that point and learned that research was not for them, so they were able to find astronomy-related jobs before spending years in graduate school).
  • Study hard for the GREs. The importance of the GRE cannot be understated. Although many schools claim that it is not the sole thing they use to choose graduate students, it certainly is the single most important criteria. An excellent GPA and fantastic references will not make up for poor GRE scores. And, when you are preparing for the GRE, don't buy the purple book. (If you are studying, you know what I am talking about.)
  • Finally, enjoy yourself. Yes, study hard, but take time to enjoy college life. Join clubs, go to football and basketball games, or whatever else you need to do to relax.

Alrighty then. Tomorrow, in the last installment, I'll talk a bit about career choices in astronomy and related areas.

Tuesday, January 24, 2006

How to become an astronomer, part 1

One of the most common questions to sites like Professor Astronomy is, "How can I become an astronomer?" Often this question comes from high-school or college students loking for a career, but sometimes it comes from experienced workers looking for a change of career.

Since I'm in the middle of hunting for jobs myself, this topic is very close to my mind right now. So I think it is also appropriate to explore here in the blog, which I will do over the next few posts. But the best place for this information is this brochure from the American Astronomical Society.

Let me point out that, even if you find that a career in astronomy is not for you, astronomy makes a great hobby. In fact, astronomy is one of the few fields of science where amateurs still make important contributions! Amateur astronomers discover supernovae (exploding stars) in nearby galaxies, discover comets, and track asteroids. Some amateurs even help to discover planets around other stars. So, if you don't have the time or skills it takes to become a professional astronomer, you can still contribute to the science. Don't be discouraged!

So, what skills are needed to become a professional astronomer? Obviously, you need to be interested in the subject. But you also need to be very good in math, as algebra, trigonometry, calculus, and statistics (among other things) are used on a daily basis by professional astronomers. You need to be comfortable using computers, as 99% of our work is done on the computer. Note this doesn't mean you have to be able to extoll the virtues of BSD Linux over Fedora Core 3 (yet), but you need to be able to pick up new computer skills quickly. You need to be able to learn on your own, be a careful worker, and be able to write/speak well.

Next time, I'll talk about what classes to take in high school and college to prepare for further study in astronomy.

Thursday, January 19, 2006

Up, up and away!

A couple of hours ago, I watched the New Horizons probe to the planet Pluto blast off on an Atlas V rocket. It was quite an impressive launch, with a 200-foot-tall rocket loaded with several hundred thousand pounds of liquid fuel needed to loft the piano-sized, 1000-pound probe into space.

Several news organizations were playing up the three-day delay in the rocket launch. This is unfair, in my opinion, because these rockets are extremely complex. If the weather is bad or the electricity is out (the causes of the delay), you risk the entire mission. In this case, it isn't only a few hundred million dollars down the tubes, but also there would be the added risk of spreading radioactive material along the eastern seaboard of the United States. Also, you are trying to hit a target smaller than the moon from a distance of 4 billion miles, so you can imagine that the constraints are pretty tight!

But, New Horizons is on its way; here's hoping for a successful mission to the outer solar system!

Wednesday, January 18, 2006

Pins & Needles

Yesterday I had my computer tuned in to NASA TV to watch the launch of the New Horizons probe to Pluto. For three hours I listened as launch control prepared for launch and then delayed for 15 minutes, then got ready to go and delayed yet again, as high winds and technical glitches finally forced the launch to be delayed until today. And then today's launch had to be delayed because the mission headquarters at Johns Hopkins University lost electricity before they could determine that everything is still okay on the probe. I imagine that everyone involved is raring to go, after several years of mission planning, several budget cuts and other delays.

I'm also sitting on pins and needles as I await news on various job applications I've put out. So far I've heard precious little, but it is the time of year when a torrent of news will soon come. I'm hoping something positive comes my way! So, I can empathize with the New Horizons crew. Best of luck tomorrow!

Monday, January 16, 2006

Pluto and Plutonium

In 17 hours, NASA's probe to the planet Pluto, the New Horizons mission, will begin its seven-year journey to the Solar System's ninth planet. At the far reaches of the solar system, there is too little sunlight for solar panels to make electricity, so the New Horizons probe is powered by 24 pounds of plutonium.

Needless to say, placing 24 pounds of radioactive material on a rocket is not done without some controversy. The claim is that dangerous radioactive material could be spread across a large area if the rocket explodes during liftoff, endangering large numbers of people.

Personally, I am confident that the launch will proceed safely and that there is little danger of radioactive release even if the rocket explodes. There is a phenomenal amount of engineering and study that goes into the design and launch of a space probe, and the amount of work increases dramatically when environmental and public safety is an issue. Given the potential risks and repercussions of a poorly-engineered launch, I feel that NASA has studied the issue.

However, I do not dismiss these protesters out of hand. They have a valid point. Radioactive material has been released from spacecraft. One of the most famous examples is the Soviet Cosmos 954 satellite, which crashed into Canada in 1978. As we explore space, we must not become careless, as two shuttle disasters have shown. Putting a heavy chunk of metal into space takes a LOT of energy (rocket fuel), and if quality control is not maintained, there can be disasterous consequences.

Sunday, January 15, 2006

100th post & Stardust returns

Well, this is Professor Astronomy's 100th post on this blog. For many people that may not be too impressive, since many bloggers post several times each day. But for myself, I see this as a landmark, given that I am notoriously bad at emailing family and friends, let alone maintaining an almost-daily post.

I am in the airport, flying back home after the astronomy conference, and I see on TV that the Stardust capsule, containing small amounts of dust from a comet and from interstellar space, has returned safely to Earth after a 7-year, 3 billion mile journey. Congratulations to the team of scientists, engineers, and other workers who successfully ran this mission. It will take years of study to tease the results from this mission, but the most stressful part is done.

Thursday, January 12, 2006

American Astronomical Society Meeting -- Day 4

Yes, I know I missed Day 3. I was in a train, travelling from Philadelphia to Washington, DC, then by Metro within D.C.

Today is my first (and only) day at the meeting. We are at the Wardman Park Marriott in Washington, just down the road from the National Zoo. Over the course of the week, over 3000 people attended this meeting. Today the numbers are much smaller, and there is a steady stream of people leaving the hotel.

This morning I had a couple of job interviews, and in 15 minutes I will be giving a talk in a topical session. Hopefully it will go well!

Wednesday, January 11, 2006

News from the AAS -- Day Two

Yesterday was the second day of the Winter Meeting of the American Astronomical Society. As always, exciting science continued to roll out, including press releases on measurements of the shape of the bright star Vega (it is spinning so fast that it is detectably flattened instead of purely round, like our sun) and evidence that supermassive black holes grow from the merging of galaxies.

The biggest news of the day was NASA chief Michael Griffin's speech to the society. In his speech, Griffin spoke of the difficulties of balancing both science and manned exploration given the limited budget of NASA. Griffin also awarded the late Dr. John Bahcall NASA's Exceptional Scientific Achievement medal in honor of Bahcall's efforts to make the Hubble Space Telescope a reality. Finally, Griffin reiterated that NASA wants to send a space shuttle to repair the Hubble Space Telescope, but that he could not promise that the mission will be ready in time to save Hubble.

Tuesday, January 10, 2006

News from the AAS - Day 1

Yesterday was the first day of the winter meeting of the American Astronomical Society. True to tradition, several news stories about astronomy research were released. The three main stories were: The North Star's closest companion was imaged by the Hubble Space Telescope, yet more evidence that black holes exist, and explaining the "warping" in the disk of the Milky Way.

Personally, I find the last of these the most interesting (though this is my opinion only). The Milky Way galaxy is flat, like a frisbee, or a vinyl record (or a CD for those of you younger than me). But the Milky Way is not completely flat -- one side of the disk (record) is pulled up, and the other pulled down. It's not unlike a vinyl record left too close to the fireplace or out in the sun.

The cause of this warp was uncertain. The most likely cause of the warp is gravity, but the known galaxies closest to the Milky Way, the Large and Small Magellenic Clouds, are not massive enough to cause the warp. In other words, their gravitational pull is not strong enough to bend the Milky Way.

Astronomers from the University of California, Berkeley used computer models to figure out how the gravity of the Magellenic Clouds can be enhanced by the Milky Way's own dark matter halo. This invisible stuff surrounding the Milky Way may actually be 90% of the mass of the galaxy! There is plenty of matter there to be able to bend the Milky Way's disk. And, not only does the dark matter cause the Milky Way's disk to bend, but it actually starts the disk "flapping", as the disk flaps up and down.


Monday, January 09, 2006

A Stardust Melody...

On January 15, NASA's Stardust mission will blaze through Earth's atmosphere, returning a precious cargo of comet and interstellar dust. Those of you lucky enough to live in Northern California or Nevada should be able to see the "shooting star" of this re-entry around 1:15am Pacific Time on the morning of the 15th.

The Stardust mission was built to collect two samples of dust. One sample comes from the comet Wild 2 (pronounced like "Vilt") and was collected in January 2004, and about 1000 dust grains, or about 1/1000 of an ounce of comet material, will be returned to Earth and analyzed by scientists. The other dust sample is about 100 particles of interstellar dust, or dust from outside our own Solar System. This dust was created by other stars, and very little of it has ever been found or studied.

To collect dust without destroying it is hard, because the spacecraft was moving at 13,000 miles per hour relative to the comet dust. The spacecraft used something like a giant tennis racket filled with aerogel, or a foamy glass. I once visited the primary scientist in charge of the mission, Dr. Donald Brownlee, and he let me hold a chunk of aerogel. It is so light, you can barely feel it in your hand.

So, after almost seven years in space and three billion miles of travel, Stardust is almost home. Here's to a safe return!

Wednesday, January 04, 2006

From observing to a professional meeting

I started the new year on top of Kitt Peak, where my collaborators and I are beginning an ambitious new project. It was our first time using a wide-field camera that was built for Steward Observatory's 90-inch Bok telescope. In a single picture, we get to see an area of sky four times larger than the full moon. Here are some pictures taken by graduate student Richard Cool: Rosette Nebula and Messier 33, the "Pinwheel Galaxy".

Last night we weren't working due to clouds and 60 mile-per-hour winds. I had to leave the mountain, as I am leaving the warmth of the desert for the annual winter meeting of the American Astronomical Society. I left a capable grad student from the University of Texas, Mukremin Kilic, in charge of observing. Tonight has been pretty clear, and tomorrow should be crystal clear, so Mukremin should get some good pictures.

The American Astronomical Society meeting will be next week in Washington, D.C. Astronomers from across North America and beyond will converge on Washington to share their ongoing research, listen to talks from important astronomers and even the head of NASA, Michael Griffen. Several press releases on cool research results will also be made, so watch the papers for some exciting astronomy news! Of course, yours truly will pay attention and let you know what is going on.

Monday, January 02, 2006

Welcome to 2006

A day ago, the Earth completed yet another revolution about our parent star, the Sun. Our planet has made the trip about four and a half billion times, but we humans always feel like celebrating the fact that the old planet finished another round. Hey, that's a good enough reason for me, too. So here's a glass to the new year!

Many news outlets this time of year rank the top news stories of the previous year and/or predict the top stories of the coming year. I won't bore you with restrospection; partly because I am sick of it myself, and partly because that would involve me having to actually work to remind myself what happened in astronomy over the past year. and if I could predict the future to tell you about this year's upcoming discoveries, you can bet I'd be on E*Trade making millions on the stock market.

Instead, I will wish everyone a prosperous and joyous New Year. And now, back to the stars!