Friday, December 18, 2009

When two might mean nothing, or it might be the future of physics


Yesterday saw the culmination of weeks of building buzz surrounding the announcement of results from one (of many!) searches for dark matter in the laboratory.  The result: two "events" that look like dark matter, but there's a 23% chance that these are just background events.  In science, 23% chance of being wrong is too high, so most people are seeing this as, at best, an ambiguous result.  Read more about the announcement here, or take it straight from the team's mouth (in PDF format).

What was all the excitement about?  Let me explain.  No, there is too much.  Let me sum up. Buttercup is marry Humperdink in little more than half an hour. (Sorry).  The story begins in the 1930s, when astronomer Fritz Zwicky noticed that galaxies in galaxy clusters were moving faster than could be explained by the gravity of visible stars, so he proposed some sort of invisible matter was responsible.  Most people (wrongly!) dismissed this idea until the 1970s and 1980s, when astronomer Vera Rubin discovered that the outer parts of spiral galaxies were orbiting faster than could be explained by the visible stars and gas alone.  About the same time, X-ray telescopes confirmed that Zwicky's galaxy clusters were more massive than the visible material alone could explain.  Meanwhile, comparison of the Big Bang theory's predictions of the amounts of different elements produced during the Big Bang with the actual amounts we see in the Universe said that much of this dark matter could not be made of normal atoms.  Skipping over many equally-important observations, the summary is that astronomy needs some sort of matter in the Universe that is different from the atoms stars, planets, and people are made out of.

Thursday, December 17, 2009

Water world, water world


An artists conception of the red dwarf star GJ 1214 and its planet
Image Credit: David A. Aguilar, CfA



Yesterday, astronomers announced that they had found a new "super-earth" planet around another star.  The team also claims that the planet must be made of a substantial amount of water.  Perhaps as interesting as the discovery is the story of how it was made and the timing of the announcement.

Let's start with the discovery.

Wednesday, December 16, 2009

In the valley of the jolly (ho ho ho!) red giant


The changing size and shape of chi Cygni
Image Credit: Sylvestre Lacour, Observatoire de Paris


Looking and behaving like one right jolly old elf, red giant stars tend to shake like a bowlful of jelly.  In a press release yesterday from the Center for Astrophysics (and, more importantly, a paper published in last week's issue of the Astrophysical Journal), a team of astronomers announced that they had obtained images of this shaking in one star, chi Cygni.  The illustration above shows the images of the star derived from their work.

Stars like the sun spend most of their lives looking a lot like the sun -- fairly small, at least in astronomical terms, fairly hot, and creating energy by fusing hydrogen atoms into helium atoms.  After some amount of time (a measly 10 billion years in the case of the sun), the star will exhaust its supply of hydrogen.  When it does so, it swells up into a truly monstrous size, and its outer layers cool off, fading and cooling from the blinding yellowish white of a star like the sun to a ruddy red or reddish orange color.  During this "red giant" stage, the star can get as large as the orbit of the Earth, Mars, or even Jupiter, depending on how massive ("heavy") the original star was.

Monday, December 07, 2009

Last chances to celebrate the International Year of Astronomy



Image Credit: IYA2009 (International Homepage / USA Homepage)


It's December, meaning that this is the last month of the year-long celebration of astronomy, the International Year of Astronomy 2009 (IYA2009).   Have you participated yet?  Although the year may be winding down and many of us are so busy that the last thing we need is more stuff to do, there's no need to panic.  Many of the official IYA2009 activities will continue into 2010 and beyond, and of course  the science itself will continue to push our bounds of knowledge about the Universe.

I'll get to a list of some of the activities you can still participate in shortly.  First, just a little background about the IYA2009, in case you were unaware or had forgotten.  The IYA2009 is an effort sponsored by the United Nations, the International Council on Science, and the International Astronomical Union.   International Years are not new; for decades the UN has sponsored scientific projects intended to bring scientists from around the world together to study a particular branch of science.  The IYA2009 is slightly different; rather than focusing scientists on a specific problem, the IYA2009 is designed to bring the public into the science of astronomy.  The effort is truly international, with, at last count, 148 nations participating in the IYA2009 in some way, shape, or form.

This year was chosen because it marks the 400th anniversary of Galileo's first observations with a telescope and the 400th anniversary of Johannes Kepler's publication of Astronomia Nova, which contain Kepler's first two laws of planetary motions.  It is hard to overstate the importance of these two events, which were crucial parts of the birth of modern astronomical science.

The main goal of the IYA2009 is to get every human on the globe to think about astronomy or our place in the Universe at least once this year.  Spend a few minutes on the next clear night looking at the stars or pondering the wonders of nature, and you've helped fulfill that goal!  You can help further by talking to your family and friends about astronomy, or just showing them the stars.

But there is so much more you can do, and you don't have to do it all this month.  The following activities will be continued well into the future, and you can help with all of them!

  • 365 Days of Astronomy -- This daily podcast gives listeners a 5-10 minute daily dose of astronomy on a wide range of topics, from exciting new research to historical astronomy to personal anecdotes by professional and citizen astronomers.  This podcast was just renewed for another year, and it needs support in the form of listeners, donations ($30/day will get your name in front of 5-10 thousand listeners!), and contributed podcasts.  You can follow 365 Days of Astronomy from their website, through iTunes, and even on Twitter.
  • Citizen Sky -- The Citizen Sky project is an opportunity for everyone to contribute to a scientific research project.  The goal is to understand the mysterious star epsilon Aurigae, a star you can see with your plain eye on any clear winter night.  The star fades greatly for about two years every 27 years, and astronomers aren't sure why.  This year, the star began fading again right on cue, and your observations over the next year or more can help us professional astronomers!
  • Galileoscopes -- The Galileoscope is a small, inexpensive telescope similar in design (but far better quality!) than the telescope Galileo used for his groundbreaking observations of the Moon, Jupiter, and Venus (among other things) in 1609.  You can buy your own for $20 plus shipping (be patient, they take a while to ship because orders are filled by volunteers and sometimes you'll have to wait on the manufacturer), or you can donate telescopes to classrooms around the world for $15.
There are undoubtedly more IYA2009 activities that will continue into the future.  This website has a listing of many of the Cornerstone projects of the IYA2009, and most of these projects will be continued into the future (including She is An Astronomer, the Galileo Teacher Training Program, Dark Skies Awareness, and Astronomy and World Heritage).

The end of the IYA2009 is just the beginning of many of the programs.  Astronomers are seeking to find the best uses for  new technology and media, as well as expand astronomy within developing countries.  We celebrate our past and look to the future.  And, like Janus, after December 31 we will be looking both backwards and ahead, celebrating the end of a successful program and the start of a daunting new task of building on that success.

It's not too late!  Come join us in the fun!

Friday, December 04, 2009

Astronomy holiday shopping guide

It's a cold December morning in Austin TX.  The forecast is calling for a light dusting of snow today, and people are freaking out.  Last night the store was nearly sold out of milk and bread, and this morning, there are several wrecks on the road attributed to "winter conditions" even though the roads are dry and the temps are well above freezing.  My inner Hoosier is laughing at Texans.

Anyway, the weather makes me realize that the holidays are not only coming soon, but virtually here.  Since previous attempts at stopping the holidays from coming have failed miserably, I'm just going to give in and write my annual admonition about astronomy gift buying.