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All posts for the year 2004

Like everyone else, I’m just stunned at the suddenness and magnitude of the disaster in East Africa and South Asia as a result of the earthquake and resulting tsunamis. This is a time when all of us in the human family need to help each other. To that end, I’ve assembled a set of links here for you (if you’re so inclined) to send aid, donations, etc. I’ll be back with more astronomy in a few days.
CNN has a listing of relief agencies geared to help the people in those regions.
Direct Relief International has set up a news center on their pages, along with donation links.
The Tsunami Help Blog has links to a number of relief efforts and missing-relatives pages.
And finally, Amazon.com has set up a direct-donation link that is funneling 100 percent of money donated to the American Red Cross for relief efforts.

We went out on Christmas night and found Comet Machholz just about where the star chart says it’s supposed to be. With a pair of binoculars we could make out a nice fuzzy glob of light. If you could take a picture of it over several minutes’ time, it would look about like this image from two of Europe’s better-known comet photographers. Notice in their view that Machholz seems to have a couple of tails. The one sweeping out from the comet to the upper left is the dust tail and the one sweeping out to the lower left is the plasma tail.
For several years while I was in graduate school I studied comets, including one named Machholz! Our team’s interest was in tracking the evolution of a comet’s plasma tail, which is formed in an interaction between cometary gases and the solar wind. The dust tail, by contrast, is made up of microscopic dust particles streaming off the comet. When I joined the team I began working on analyzing images of Comet Halley and its nicely active plasma tail. We wanted to track it throughout its tour around the Sun, and later on we did the same with others. The biggest result was a book published as part of the International Halley Watch project called the International Halley Watch Atlas of Large-Scale Phenomena. It was published through the University of Colorado in a limited edition run, and I was astonished to find it the other day on Amazon.com (although I did know it was selling at various times on Ebay). In fact, I have eight copies of it here at my office.
For the project I and other team members (Jack Brandt, Yu Yi, Marty Snow, Marlon Caputo) went through about 2,500 images of Comet Halley submitted by astronomers from around the world. We measured the size and angular orientation of the plasma tail and correlated it with the comet’s location in the solar wind. Then we arranged the images in a time sequence starting from late 1985 to about June 1986. If you flip through the book, you can see the tail change drastically as Halley neared the Sun and visited various latitudes of the solar wind.
My job was mostly to analyze the images, and then lay them out in the book for publication. So, while I’m not listed as one of the book’s authors, I am acknowledged for my contributions, and it was a most satisfying and interesting project with which to be associated. And, I learned a lot about comets and the solar wind in the process.
We went on to study other comets: Machholz, Schwassman-Wachman, DeVico, Mueller, Hyakutake, and Hale-Bopp. We gathered up images for each comet, and correlated their positions in the solar wind with their appearances, and also with data from the Ulysses spacecraft, which was in the same “regime” of the solar wind as each of the comets for various periods during their respective orbits. For Hale-Bopp, we took observations at the University of Hawai’i 88-inch telescope on Mauna Kea during November 1996 to see if we could catch the “turn on” of the plasma tail. That was a personal thrill for me, even though our data showed that at the time the plasma tail hadn’t yet started to grow.
Nowadays I’m out of the plasma-tail research business, although some of my colleagues, most notably Jack Brandt (team leader, close friend and co-author, currently at the University of New Mexico), continue to pursue the study of correlations between cometary plasma tails and the solar wind. He continues to publish papers based on data we took during my tenure at CU, as well as on data he’s gathered since that time on other comets. We made some good contributions to the comet research literature. Plasma tails are a fascinating way to see the Sun’s influence on things even as small and evanescent as a comet!

Each season of the year has its distinctive “sky look.” For stargazers in the Northern Hemisphere, December brings Orion up front and center high in the southern sky. For Southern Hemisphere sky watchers, Orion’s still one of the main attractions, but he’s apt to be on his side, or even close to upside-down. I’ve often wondered what it would be like to appreciate Orion during the holidays from, say, a dark-sky site in Australia or South Africa. December heralds early summer for the folks in those areas, a time of warmth and relaxation. Whereas, in the north, many of us are doing our best to stay warm and only duck outside for a little while to take in the sky sights.

I was at a party a couple of weeks ago and talking to a colleague from Australia. He mentioned the incredibly active amateur astronomy groups that meet and view the sky. So, on a day when it has been not much warmer than 20 degrees (F) (-6 Celsius) I decided to do a little web surfing for southern hemisphere sky gazing web sites. One of the first I ran across was Rogers Website of Southern Amateur Astronomy. Even if you’re not living in the Southern Hemisphere, it’s fun to see his writeups about what SoHemi observers are seeing these nights.

Another one I enjoyed reading was Southern Sky Watch. It gave me a great perspective to read, “Summer is here once more, and the beautiful constellations of Orion, Taurus and the magnificent rambling constellations of Carina, Puppis, and Vela grace our skies again.”

The Southern Sky Watch had a link to Steve Voss’s Aurora pages and a selection of gorgeous auroral images taken from New Zealand.

I also ran across the Astronomical Society of Southern Africa. It’s a venerable group, formed in 1912 and is quite active. It has a lot of really good resources for Southern Hemisphere observers, including star charts and observing hints.

Sometimes those of us in the Northern Hemisphere forget there is another half of the sky to explore, and equally avid fans of stargazing under that sky. I know that sky came alive for me when I spent several weeks under it, teaching others how to find their way among unfamiliar star patterns. It’s an experience I think everybody should haveā€”but until you can go for yourself, do some browsing around and see how the other half lives!