27 Feb 2005
I just about missed it. Winter nearly whisked by without a mention here of some of the wonders of the southern hibernal sky.
That was a close one.
Now, here’s the lowdown on what’s up in those glorious skies at the end of this cold and very wet month of February.
Let’s assume the best, that in the next couple nights we will have cloudless skies. The nearly three-week-old moon doesn’t rise until late evening so star gazing and planet seeking should be very nice.
And let’s use Orion as our wayfinder for our mini-adventure. You’ll find our hunting friend in the southwest skies, that great stellar quadrangle cut through by his famous belt.
At his “top left” shoulder there’s the famous red giant star, Betelgeuse. “Giant” is the right description for this dying star since he is over 600 times bigger than our sun. Put him where our sun is and he’d swallow all the planets out to and beyond Mars.
Opposite Betelgeuse, to the lower right, is bright blue Rigel. Both Betelgeuse and Rigel each pour out more energy than 50,000 suns. That’s why they can abide at their great distances of hundreds of light years – thousands of trillions of miles - and still appear as bright as they are.
But the energy leader of the Orion clan is that middle star in the belt. There lies Alnilam, a star that spews more than 112,000 suns worth of energy. It’s a fiercely violent star but is dimmer than the other stars in the great family because of its distance – more than 1350 light years from earth.
A quick trip through Orion would be incomplete without at least a mention of the most famous star nursery in the sky, the Orion Nebula.
Located just below the Belt, here are dozens and dozens of stars being formed in a luminous cloud of dust and gas. But, amazingly, only one star is lighting up the entire cloud, a bright O-type star in a tiny cluster of four named the Trapezium Cluster. One can see both the Nebula and the four tiny Trapezium through even inexpensive backyard scopes.
Closer - much closer - to Earth is the intensely bright star almost due south this evening and a little to the east of Orion. That is Sirius in Canis Major. This beauty is not so bright because it’s so big, but because it is so close. A mere stone’s throw 8.6 light years away, it is the closest star we can see this far north, besides the sun of course. (In case you’re wondering, southern folks can see the Proxima and Alpha Centauri pair, the closest stars to Earth overall.)
Now our next stop on the tour is a planet, but it will take a little sleight of hand to get there. Imagine a line made from the top two stars of Orion - from Bellatrix at the upper right through Betelgeuse at the upper left. Holding your arm out and spanning your hand, imagine a line extending out to the left from Betelgeuse, curving slightly upwards, two hands spans worth of sky away.
There you will find a bright golden “star” near two bright, but slightly dimmer stars. That would be Saturn, the ringed beauty. The second largest planet in the solar system, it is easily spotted through amateur scopes and is a favorite at star parties.
Its main moon (one of over 30) is Titan, the rare satellite that can brag of its own thick atmosphere. Titan has been making a lot of news lately since we’ve managed to land a probe there, just weeks ago.
The spacecraft Cassini, which finally arrived in a comfortable orbit around Saturn last year after its launch back in 1997 - it takes a while to get certain places - dropped a probe named Huygens down onto chilly old Titan to see what makes it tick.
You can see all the great images from both Cassini and the Huygens probe of Saturn’s amazing rings, Titan’s spooky other-worldliness, and other bizarre creatures in Saturn’s zoo of satellites at the website for the mission: http://saturn.jpl.nasa.gov.
Hope our little tour of the southern skies was enlightening. Our next scheduled planetary package tour will be in spring starring the King of the Giants – Jupiter. We’re taking reservations now.
17 Feb 2005
Astronomy is like any other discipline, one with its own unique language and special heroes. And like the other disciplines many of these words and names get twisted about or misunderstood or are just plain hard to say. Here are only a few of the many examples I’ve picked up over years of teaching this divine discipline.
The term “astronomy” itself is one that is often misunderstood. When telling someone that I teach astronomy I often get a response that goes something like, “Oh, and what sign are you?” or “Do you know how to do horoscopes?” I have to explain then, in the nicest way of course, that what I teach is the science of astronomy, the study of the heavens, not astrology, its pseudoscientific etymological cousin.
When I tell my class that the next chapter we’ll be looking at is about cosmology, there is always the one well meaning, if not well read, student who exclaims something like, “What do make-up and lipstick got to do with stars?” Once I come to, I explain - in the nicest way, of course - that cosmology is the study of the entire universe from birth to impending death. It is not cosmetology, the study of cosmetics and their many interesting uses.
There are plenty of candy references I get to put up with, too. Besides the obvious planetary namesake that is the Mars bar, which recently went down the Street of Discontinued Candies - but which you can still get on eBay! - there is the astronomically christened Milky Way bar.
Recently it has been discovered that our galaxy, the real Milky Way, has a bar-shaped thicket of stars through its center. Our home is classified as a “barred spiral galaxy.” But don’t make the mistake of asking what the bar in the Milky Way is made of unless you want to hear the quirky answer, “Fluffy milk chocolate?” followed by some goofy laughter.
And, yes, there really is a type of cosmic phenomenon called a Starburst. And no, it is not composed of a multi-colored assortment of chewy fruit-flavored candy. It is a place of intense starbirth that can light up entire areas of galaxies.
Then there is the stockpile of singular names of astronomers past and present. I can lose a class for a couple minutes by just mentioning or trying to pronounce some of these names.
For example, Annie Jump Cannon is not a complete, but ungrammatical sentence about a woman leaping over a large cylindrical weapon. It is the real name of a very famous pioneering woman astronomer who was first to classify stars – over a half million of them - back in the early 20th century.
Other tongue-twisting topliners are Tycho Brahe, the great pretelescopic Danish observer; Karl Schwarzschild, a pioneer in the field of black holes; the extraordinarily eccentric Fritz Zwicky out of Caltech, one of the first astronomers to consider the now vital tool of gravitational lensing; Enjar Hertzsprung, another Danish astronomer who, with another astronomer by the relatively lackluster name of Henry Russell, gave us the most famous star diagram in astronomy.
In my opinion, though, the king of all names unique, and the moniker that offers a great chance for me to embarrass myself in front of my class, belongs to Subrahmanyan Chandrasekhar (pictured here). He was the world-class astronomer who helped define the mass limits of dead stars called white dwarfs. Mercifully for me, everyone called him Chandra for short. The Chandra X-ray Observatory, a cutting-edge tool for discovering the invisible universe, was named for him.
And, of course, even astronomy has its share of wordplay in the form of off-color double entendres. But I won’t foul this column with any of them except to ask you – in the nicest way, of course - to pronounce the seventh planet out, Uranus, with the accent on the first syllable, something like “YOUR-un-us.” If we all pronounced it that way, astronomy instructors could trade in hours of snickers for quality learning time.