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Globular Clusters
The Galaxy >
Summer is a great time of the year to be taking a look at globular clusters. If you can get yourself a pair of binoculars, or better, a small telescope, you should go out some time soon on a moonless night and appreciate the subtle beauty of one of these creatures in the dark.
Globular clusters, aka "globs" in the astro-biz, are ... well ... clusters of stars that are shaped like ... globules! Scientific terms may not be too poetic, but they're pretty descriptive.
Globs aren't just cute wee clusters of stars, however, like grapes on a vine. Oh no! They are menageries of stars that number in the hundreds of thousands! If we lived in a glob we'd have a night sky with tens of thousands of brilliant, bright stars all round. From here, though, they appear only as symmetrical fuzzballs through an eyepiece.
But their descriptive moniker doesn't explain why they are the way they are or even how they got here in the first place. Inquiring minds for the last hundreds of years wanted to know.
So inquiring minds found out.
As early as the beginning of the 20th century, it was believed that our solar system was the center of the Milky Way Galaxy.
But then Harlow Shapley came along. (Yes, Harlow Shapley!)
While studying the distribution of globs around the skies Shapley realized that they aren't hovering around our system; they seem to be hanging out in an area way over there in the constellation Sagittarius. He assumed these little clusters were moving about that area because that was the center of the Galaxy. He was right.
With that observation, and with more he and his colleagues would make in the next decades, they painted a New Picture of this hugely massive universe we live in and changed the face of astronomy for good.
It turned out that globs are not only the most compact groups of stars in our galaxy, they are also its oldest stars, the oldest amongst them being over 10 billion years old! In comparison, our sun is a second or third generation star in the disk of our galaxy and is only a middle-aged 5 billion years old.
The latest and best theories say that globular clusters were the first things formed in our galaxy, before it flattened and went spiral leaving the globs to hover about it like bees around a huge flower. Globs, it turns out, are the senior citizen communities of spiral galaxies and as such should be treated with the respect they deserve.
You can spot some globs tonight! Go out at about 10 PM, with binoculars or telescope and look directly above you. There is center of the constellation Hercules which is shaped like a keystone. Look for the two keystone stars on the western side. Between them you'll see a fuzzball. That's M13, one of the most stunning globs of all.
Now look to the south. See that reddish star to the "right" of Mars? That's Antares in the constellation Scorpius. Just to its right is another fuzzball, the glob dubbed M4.
Now look to the "left" about 30 degrees, to the teapot-shaped constellation next door to Scorpius called Sagittarius. Just to the left of the top star of The Teapot is another glob, M22. The heavens have many, many more you can discover for yourself just by carefully scanning the skies.
Have fun! There are maps and images awaiting you at firstlightastro.com. Until next time, clear skies and happy hunting!
Posted by Administrator at 2001.07. 7 08:22 AM | Comments (0)
