Wednesday, October 28, 2009

A prized lecture


Antoinette de Vaucouleurs
Image Credit: McDonald Observatory



Today we were treated to a lecture in memory of Antoinette de Vaucouleurs, who was an astronomer here at the University of Texas at Austin for 25 years.  She is well-known for extensive work on the photometry and radial velocities of galaxies, often collaborating with her husband, astronomer Gerard de Vaucouleurs.  She continued working until just ten weeks before her death of bone marrow cancer in 1987.  You can read more about her life and work here.


Every year, the Department of Astronomy invites an outstanding astronomer to receive a memorial medal, and to give public and research lectures in recognition of their lifetime of achievements. Past recipients read like a who's who of BIG astronomers, including Margaret Burbidge, Vera Rubin, Don Osterbrock, Sandy Faber, Frank Shu, and Nobel Laureate John Mather, among many other equally-distinguished astronomers. 

This year, we had the honor of hosting Dr. Rashid Sunyaev, director of the Max Planck Institute for Astrophysics in Garching, Germany, and Chief Scientist of the Russian Academy of Sciences Space Research Institute in Moscow.  Dr. Sunyaev is well-known for making many important predictions about the cosmic microwave background and X-ray radiation from black holes, many of which have been found to be true.  One of the things that I particularly like about much of his work is how he focuses on the observable signatures of the physical objects he is interested in.  It's one thing to hypothesize about some of the earliest structures in the Universe; it's another thing altogether to also tell us observers how we might be able to see these structures.

During today's research lecture, Dr. Sunyaev gave an overview of his most famous work on clusters of galaxies and cosmology, sprinkled with personal anecdotes about his advisor Dr. Yakov Zeldovich.  He also gave some advice to the graduate students, such as to publish results about "beautiful physics", even if the observations needed to test the prediction seem technically impossible, because we don't know how far technology may go in the next decades.  He also quipped that theorists have to be smart, but it's okay for them to be wrong, while observers don't have to be smart, but they'd better always be right.  Sunyaev was also very excited about some new results that will be coming out of the Planck satellite and telescopes at the South Pole, but he couldn't tell us details about the results yet because the findings are still being verified.

It is always a real morale booster to see talks by people who are so clearly passionate about their research and optimistic about the potential for new, exciting discoveries in the future.

Saturday, October 24, 2009

Clear Skies Abundant


Image Credit: McDonald Observatory

Crystal clear skies.  Maybe even clearer.  This is how I like my observing runs. 

I'm finishing the 10th night of a 13-night observing run dedicated to looking at my favorite white dwarf stars.  I haven't been out here all ten nights, as two of my colleagues kindly volunteered to cover the first nine nights of the run.  In those nine nights, the weather was ideal for seven nights.  Tonight has also been great, and it looks like at least two and maybe all three of the remaining nights will also be clear.  Given that two-thirds of my telescope time has been clouded out over the past 18 months, I'm grateful to finally be getting a lot of high-quality data.

This run has had me worried for a long time, and not because of triskaidekaphobia.  Two days before the run started, one of my volunteers had a family emergency, so I had a stressful 48 hours rearranging the observing schedule.  Then one of my cats got quite ill, and I wasn't sure how to make sure she was taken care of while I was gone.  (Thankfully she recovered enough that my pet sitter has been able to take care of her.)  Then one of my volunteer observers fell ill here at the mountain (she fully recovered).  About the same time, I got word from Arizona that one of my colleagues there was in the hospital and not doing very well (he's not recovered, but at least is stable and was able to go home).  Lastly, as I was preparing to leave Austin, I accidentally dinged the side of another car with my car door; the owner of that car got absolutely livid over the 1/8-inch long scratch (no dent, but I did flake the paint and primer off), so I spent an hour on the phone with insurance.

Still, the clear skies and good data are worth most of the stress.  The moon and Jupiter dominated the evening skies, and all morning I've seen a dribbling of bright, fast-moving meteors, the last dregs of this week's Orionid meteor shower.  Now the planets Venus and Saturn are rising, and the first hints of dawn are on the eastern horizon.  Time for bed!

Wednesday, October 21, 2009

Galilean Nights this weekend


Galilean Nights Teaser Poster
Image Credit: IYA2009 / James White



Galilean Nights, one of the cornerstone projects of the 2009 International Year of Astronomy, takes place around the world this weekend!  The goal of the weekend is to encourage those around us to look through a telescope at the same celestial objects that Galileo looked at 400 years ago, leading to a revolution in our understanding of the Universe and giving a new birth to the science of astronomy.  This weekend, the moon and Jupiter are both well-placed to see in the early evening sky. And, if you are a morning person, Venus and Saturn are both low in the pre-dawn sky, rising about 1 to 1 1/2 hours before the sun.  The Orionid meteors, bits of dust shed by Halley's Comet long ago, will also be an occasional visitor in the evening and morning skies. 


Do you want to participate?  You don't need any experience.  Many planetariums and observatories will be having festivities; contact them to find the place and time.  You can also find a nearby event from the Galilean Nights website: http://www.galileannights.org/find_event.html.  If you own a telescope, why not pull it out on a local sidewalk and show off the moon and Jupiter this weekend to friends, family and neighbors?


If you don't have a telescope and can't find a nearby event, you can also go out and look with your eye.  The moon will be obvious, and the planet Jupiter is the brightest object in the evening southern sky (if you live north of the equator).  400 years ago, Galileo alone knew that Jupiter had its own moons performing an intricate dance around it; now you, from the comfort of your own living room, can use a computer to see pictures of those moons taken by robots, pictures that give some hope that some other form of life may be swimming in oceans under dozens of miles of ice.  And think about how we now can find worlds like Jupiter around stars hundreds of light years away, and how very soon we will know about Earth-like planets around those same distant stars.

Sorry!

Sorry to a handful of commenters whose comments were awaiting moderation and just got rejected.  I was trying to reject an advertisement and accidentally clicked on the "Reject All" button.  My goof.


Just as a brief reminder on comment policy, any comments on posts over 7 days old have to be moderated to keep spammers away.  It can take me a few days to get around to it, depending on my schedule.  Thanks for your patience.  I accept most comments, but will reject anything that is obviously spam, that is way off topic, that is not family-friendly, or that is just a flame war.

Tuesday, October 20, 2009

Stop the world and let me off!

The past two weeks have been horribly busy with all kinds of things I hope to blog about over the weekend.  Yesterday and today I'm attending a postdoc-led symposium here at Texas.  (Here is my blog post from the last edition of this symposium two years ago).  Alas, it's keeping me even busier, but I'll summarize all the cool things I've learned in a few days.

Friday, October 16, 2009

I, for one, welcome our new grasshopper overlords




Image Credit: McDonald Observatory / MONET / D. Doss

What was that last night in the skies above McDonald Observatory?  An odd cloud?  An alien spacecraft arriving from the Orion Nebula?  Or (shudder) Melanoplus lakinus? We may never know.  By the time crack government agents arrived, it was gone.

Friday, October 09, 2009

Did NASA's Moon impact Fail?


Palomar Observatory's image of the LCROSS impact site
Image Credit: Palomar Observatory / Caltech


No. At least, not yet, and I don't think it will.

For a few months now, NASA has been hyping this morning's impact of the LCROSS spacecraft with a shadowed crater on the Moon.  Many websites (including this blog yesterday) passed on information on how people with 10-inch or larger telescopes could watch the event, yet professional observatories with 200-inch diameter telescopes didn't see anything obvious.  Because of this, many websites, bloggers, and news casts have painted the LCROSS mission as a fizzle and a failure.  This is as unfair and exaggerated as the predictions of spectacular fireworks were.

I do believe now that NASA overhyped the LCROSS impact, at least in terms of what we might be able to see from the Earth.  But I do not believe the mission has failed.  And that's because science is not about getting the answer we want, it's about getting the answer right.

Thursday, October 08, 2009

Two impacts that will happen, one that won't




NASA's LCROSS spacecraft and its Centaur booster rocket
Image Credit: NASA



Early tomorrow morning, the moon will be hit by two fast-moving bits of space debris.  In 2036, the Earth will almost certainly not be hit by a 250 yard-wide rock.  All three of these pieces of news make me happy.


First, the moon.  The two bits of "space debris" are NASA's LCROSS probe and its spent Centaur booster rocket.  The rocket, weighing in at about 2.5 tons, will hit first, impacting the crater Cabeus (near the moon's south pole) at 7:31 am (and 19 seconds) EDT tomorrow, while moving at a speed of 9000 kilometers per hour.  This hit should gouge a crater about 20 meters wide and 5 meters deep, and may toss as much as 385 tons of lunar soil and rock into the air.

NASA wants this plume of debris to be tossed up, because the LCROSS spacecraft is going to fly through the plume, taking pictures, analyzing the chemical makeup of the debris, and sending that information back to Earth before it collides with the moon itself 4 and a half minutes later.  That impact will create a second plume of debris.  Earth-based telescopes on the night-side of the Earth will be staring at and analyzing the impact site, too, assuming the weather is good.  (The weather at the observatories in Hawaii is looking chancy).

Wednesday, October 07, 2009

2009 Nobel Prize for Physics Part 2: Fiber Optics


Fiber optic cables used in McDonald Observatory's HETDEX project
Image Credit: HETDEX / McDonald Observatory



As I mentioned yesterday, this year's Nobel Prize in Physics was shared between scientists who developed digital imaging circuits known as Charge-Coupled Devices (CCDs) and a scientist, Dr. Charles Kao, who designed the first fiber optic cables that were useful for long-distance data communication.  Yesterday I blogged about the astronomy uses of CCDs, so today I'll talk about the astronomy uses of fiber optic cables.

At most telescopes, there are two primary kinds of instruments.  One kind is the imaging camera, which simply takes pictures of the sky.  That's easy enough to understand, and fairly straightforward to build.  (Don't get me wrong, building any astronomical instrument for a big telescope is very hard.)  The other type of instrument is a spectrograph, which splits light into its component colors.  These spectra are most often used for determining the chemical composition of things and for measuring how fast things are moving.

One problem with spectrographs in the past has that the number of stars or galaxies you can look at at one time is limited.  Some spectrographs only allow you to look at one star (which is fine if there's only one star in some area of the sky that you are interested in),  Some allow you to look at multiple stars or galaxies, but which ones you can look at are constrained by geometry -- you can't analyze spectra of individual objects if they criss-cross or lie on top of each other.  And if you are looking at a two-dimensional object, like a galaxy or nebula, traditional spectral only allow you to get a  spectrum of  a long thin slice of the object.  So, how can we get around these problems?

Tuesday, October 06, 2009

And the Nobel Prize for Physics Gadgets With Huge Astronomy Impact Goes To...


Many people will be blogging today about today's announcement of the 2009 Nobel Prize in Physics, what the awards are for, who did what, and who didn't get recognized that should have.  so I thought instead I'd focus on the astronomy aspects of today's awards, which are very important.  First, one paragraph on today's awards.


This morning, the winners of the 2009 Nobel Prize in Physics were announcedDr. Charles Kao won half of the prize for making some tremendous contributions in fiber optics that led to their usefulness for communication. (Contrary to some reports I've read, Dr. Kao did not invent fiber optics; he and his collaborators found a means to allow fiber optics to send messages over long distances, necessary if you want to make a phone call via fiber optic cable across a continent or ocean.)  Dr. Willard Boyle and Dr. George Smith jointly received the other half of the award for their work on charge-coupled devices (CCD), which are one of the major types of digital cameras.  Most cheaper digital cameras, including, most likely, any that you own, use a different type of digital imager called CMOS (read here to learn about the difference), but the CCD has traditionally provided better images and better sensitivity.


Both of these achievements have had crucial impacts on astronomy.  Today, below the jump, I'll talk about the CCDs, and tomorrow I'll talk about fiber optics.

Friday, October 02, 2009

Help astronomers support public education in science


When my daughter started school, I was shocked to learn how dismal the funding levels for public education truly are in much of the country.  Every year, teachers send home wish lists asking for donations of supplies for their classrooms; if these items are not donated, the teacher has to pay for them out of her already meager salary.  And we're not talking about "luxuries" like computers and other technology, we're talking absolute basics: pens, pencils, paper, even Kleenex.  What kind of country is this where we have to ask teachers to buy Kleenex for their students??  It makes me livid every time I think about it.  And, with the current bad economy, classrooms are being squeezed even more than normal.


Anyway, the folks over at the Cosmic Variance blog (another astronomy and physics-related blog run by some darn good scientists) are participating in a friendly fundraising competition run by DonorsChoose.  DonorsChoose allows people to donate money directly to individual classroom projects in public schools in the United States.  Basically a teacher proposes an activity, asks for the money she/he needs to do the activity, and you get to choose which activity you want to help fund.  Since they're all scientists, the Cosmic Variance folks have identified several science-related projects, and are trying to raise more money for these projects than other teams.


In short, you can directly further American science (and/or non-science-related) education by donating as little as $5, and also help a small band of astronomers win a friendly competition.  To donate money for the Cosmic Variance team effort, click here.  To read more about DonorsChoose, to start your own team, or to choose non-science related projects to donate to, look here.  And, lastly, encourage people you know to give what they can.