Category Archives: amateur astronomy

Tell The World About Astronomy

Or, Maybe Just Your Friends, Family and Maybe the Neighbors

Next year is the International Year of Astronomy, formally referred to often enough as IYA 2009. It’s a formally declared event (by the United Nations, no less) and many astronomy-oriented organizations around the world are touting IYA’s activities. If you happen to belong to an astronomy club or work at a planetarium or are a working astronomer, you’ve probably heard about IYA and have been encouraged by others to participate.

If you’re an astronomy “civilian” you may or may not hear about it, but if you’re interested in participating, the link above will take you to a web site full of information about getting involved.

One of the groups that’s working to get the word out about IYA and astronomy is the Astronomical Society of the Pacific. This organization has been around for more than a hundred years and is focused on teaching everybody about astronomy in whatever way works best. I’m a member and I have always encouraged teachers, amateur and professional (and armchair) astronomers to join, too.  You don’t have to live anywhere near the Pacific, you just have to like (or be interested in liking) astronomy.  If you’re a teacher, they have priceless resources about how to bring the wonder of the stars to your students.  If you’re an astronomy professional, the organization has a professional-track set of publications that you probably already know about (or if you don’t, you will).

So, go on over to their site and check it out — there’s a lot of useful information about how you can spread the word about astronomy to your intimate circle of friends and family. And, you’ll also see what they’ve got planned for IYA 2009.

Go on — give it a try!

It’s Classified, Part II

Sorting out Some of those Fuzzy Things

Back when people started studying the sky with telescopes, it didn’t take long for them to run across fuzzy-looking things out there. Charles Messier, an 18th-century French astronomer took to the skies each night for many years, searching out comets (which are fuzzy-looking things). Along the way he found other things that didn’t quite resolve into starlike points of light. His list of “fuzzy things in the sky” is the root of a deep-sky list that began with the so-called “M” (Messier) objects, but is extended out to the New General Catalog (NGC, created in the 1880s) and other surveys. Not everything those surveys contain are nebulae. Some are clusters of stars (which can look fuzzy, especially through an not-quite-powerful-enough telescope), and some are galaxies.

Galaxies beyond the Milky Way (our home galaxy) were (at first) just classified as “nebulae.”  They were difficult to resolve through low-power telescopes (just as they are today), but as telescopes improved, so did the view. Eventually, galaxies got separated out from things like the Orion Nebula (M42 in Messier’s list) and astronomers started sorting these “nebulae” by their shapes. The Large and Small Magellanic clouds were the first to be observed from Earth, and they were called what they looked like: clouds. After the telescope was invented and put to use by Galileo in the 1600s, later astronomers (like Messier) found these nebulae to devolve into two forms: elliptical and spiral.

As astronomers got better and better telescopes, they started seeing different “forms” of elliptical and spiral. In fact, it pretty quickly became clear that while no two galaxies were exactly alike, there were some characteristics that could be used to sort them into useful bins for study.  A lot of work (and argument) got done by Edwin Hubble, who formulated the sequence we use today to classify galaxies by their shapes.

Image:Hubble sequence photo.pngThis is the basic Hubble Sequence for galaxy shapes (often called “galaxy morphology” in the astronomy community).

You can pretty clearly see how different the shapes are. As with stars, you can think of the classification types of galaxies as shorthand for a longer story about how each one formed and evolved over time.  There’s also a side story for each type about the families of stars that inhabit them, and there’s an evolving story that is yet to be unraveled about the influence of dark matter on these galaxy shapes. Galaxy studies today are as hot and heavy as ever, and they play heavily in explaining the evolution of the cosmos and its structure.

Voorwerp imageThere’s a kind of interesting side-note to galaxy studies, and it involves anybody who wants to get online and help astronomers classify galaxies. Surf on over to the Galaxy Zoo and you can learn how to sort galaxies by shape (and other parameters). I’ve done it, and it’s actually a very interesting way to learn a little something about galaxies at the same time you’re contributing to science.  If you’re lucky, you might find something interesting that astronomers have never seen before — just as Dutch school teacher Hanny van Arkel did. While searching through the galaxies at the zoo, Hanny found a “ghost” object that astronomers have now named “Hanny’s Voorwerp” (the green thing in the image at right).  I suspect now that Hanny’s paved the way, a lot of other astronomy-minded folks will want to follow in her path.  Check it out and become part of the “classification team.”