Tiger Star

My favorite stars are out this time of year. Bright, colorful stars, with evocative names. Procyon. Sirius. Aldebaran. Capella. All of them are around the general area of Orion.

This one, Betelgeuse, is a gorgeous red giant in Orion, in the upper left-hand corner. It forms the top bit of Orion's left arm (Betelgeuse actually means "armpit of the Great One"). This picture, from Astronomy Picture of the Day, shows it not to be an even red, but rather spotted and striped in shades of orange and red and white. It looks a lot like a tiger to me.

Red giants are at the very end of their lives. So Betelgeuse is at the top of the list of stars most likely to explode soon. Soon, in astronomical terms, means it could be next week, could be in a million years.

Just Look Up

I was out in the back yard with binoculars last weekend trying - unsuccessfully - to find Comet Kushida (a bigger one, Comet Lulin, is at full brightness next month). But it was a crisp, clear night, and I amused myself by looking at the Orion Nebula (the middle "star" in Orion's sword), the Hyades star cluster (just to the right of Orion, in Taurus's head), the Pleiades cluster (up and to the right of the Hyades, looks like a big fuzzy thing when seen by the naked eye; the seven biggest stars are said to be seven sisters driven mad by moonlight). I got spoiled by my telescope and had forgotten how much you can see with just binoculars. So if you've got some, go out there and have a look around.

If you don't have binoculars, go out there and look around anyway. Orion and the surrounding stars are in full glory now. So here's a primer. These were the first star names I committed to memory upon getting sucked into astronomy, and I continue to have a real fondness for them. These are the brightest stars in the winter sky, often called the Winter G, or the Winter Football, because of the shape.


We'll start with Betelgeuse (pronunced Beetle juice, meaning literally "the armpit of the great one"), Orion's left arm, a very old red giant that I've read is one of the most likely stars to explode into a supernova in our lifetime. Might happen in 100,000 years. Might happen tonight.

Go from Orion's left arm down to the right leg. That's Rigel, a very young bluish star.

Go below and to the left of Orion to a very bright star, Sirius. This is the brightest star in the sky. You can use it as a test to tell if something is a planet or a star: compare it to Sirius. If it's brighter than Sirius, it has to be a planet.

Go above and to the left of Sirius now, to the next bright star. That's Procyon. I love that name: Procyon. It got alotta mentions in The First Novel.

Above Procyon are two stars side by side. They are the twins, Pollux and Castor, in Gemini.

Go over now, above Orion's head. The bright star up there is Capella. Now go down, to the right of Orion. That's Aldebaran, in Taurus, another beautiful name.

So put on a coat and go outside tonight and try to find them all. The names alone are worth memorizing, because they're so fun to say, so pretty to hear, so evocative. But being able to pair the name with the star itself adds a whole new level of meaning.

Plus there's a chance, albeit slight, you'll get to see Betelgeuse blow up!

I Spy With My Little Eye

That this looks like a giant eye in space is only the mildly cool bit.

The wildly cool bit is what causes the image to form. It's a gravitational lens, otherwise known as an Einstein ring.

The "pupil" of the eye, at center, is a galaxy 2 billion light years away. Directly behind that galaxy is another one, 11 billion miles away.

Follow me here: the extreme gravitational forces from the close galaxy bend the time and space around it, forming a sort of lens. Not figuratively. Literally. It's a giant lens made not of glass, but of space itself. Let me repeat that: it's a lens made of bent space. The lens distorts and magnifies the light from the faraway galaxy, bending it so it looks like a bright ring around the close one. Normally, the faraway galaxy would be too faint to see. The lens magnifies the light so that we can.

I don't know why it's blue. Perhaps it's a false color image. Or a Doppler shift of some kind.

Einstein predicted this kinda stuff would happen if we looked deep enough into space (something we couldn't do at the time he predicted it). That's why it's sometimes called an Einstein ring.

Is that cool, or what?

I grabbed the image, and the details, from the always interesting Bad Astronomy blog. I asked him why it was blue, but he's too famous to answer. He even gets interviewed on Art Bell!

Anyway.

While I'm at it, another space eye.


This is the Helix Nebula, sometimes called the Eye of God Nebula. It is much closer - a mere 700 light years away - and was created by the death of a star in our own galaxy. The resultant explosion created a tube of glowing gas along the poles of the star, and we're looking down that tube. Look closely and you can see original star, at the center of the picture.

First photo is from the Keck observatory. Second one is from the Hubble. Both are from NASA.

The Wonderful

This isn't a comet.


It's a dying star. With a tail. Its name is Mira ("the wonderful") and it's a fairly typical star. Except for that tail. It will die within the next several hundred thousand years or so.

As it burns up all its hydrogen and moves on to heavier fuels, it shakes and shudders in a series of expansions and contractions, blowing off outer layers of gas with each explosion. Death spasms. And a couple things happen. One, Mira isn't round, so these explosions are asymmetrical and send it hurtling off into space, screaming along at 80 miles a second.

Two, the outer layers of the star are blown off and left behind, which is what's forming that tail. Phil Platt over at Bad Astronomy says to "imagine running down the street with a smoke bomb in your hand." It's thirteen light years long. That's pretty big. If you look closely you can see the bow shock in front of the star, where the material the star is plowing through is building up. And the bright tendrils of material coming off the tail will eventually be folded into the creation of new stars, and new worlds, so you've got the whole life forming from death yada yada yada going on.

I wrote a novel several years ago that used the life and death of stars as an ongoing metaphor, and the crux of it was that when stars die they leave these gorgeous nebulae behind, each one complex and unique, with names like the Cat's Eye, the Ghost Head, the Tarantula, the Witch's Broom. These nebulae are around for the blink of an eye in terms of stellar lifetimes, but in that fleeting moment they shine across the heavens.

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I got an Excellent Blogger award this week from Jo, who writes of color theory and takes wonderful pictures and draws little faces on her husband's toenails on April Fool's Day. Check her out. And thanks, Jo! I think blogger etiquette requires that I pass awards along to others, but I'm pretty new at this whole bloggy thing, so I feel a little weird giving awards to folks who have been doing this longer and better than I. But you know who you are. So consider yourselves awarded.