From Saipan to the south pole

In the wake of Super Typhoon Vongfong you might feel like you need a break from reality. Well, I’m just the man for that, so let’s indulge some armchair travel. I’m going to pick a destination that’s pretty weird so we can lose ourselves in some new thoughts.

As for the destination, it’s the south pole.

Oh, not the Earth’s South Pole. It already gets plenty of attention in documentaries and cute penguin photos.

No, today’s armchair flight is to our galaxy’s south pole. This is known, logically enough, as the galactic south pole. It’s certainly weird enough to take your mind away from your earthly concerns.

In fact, not only is there a galactic south pole, but it’s also visible from Saipan this time of year.

Will I tell you how to find it? Yes, I will.

Is it worth finding? Oh, no. Not at all.

To the bare eyeball it’s just a bald patch of black sky. But it’s sure an esoteric score, since even many seasoned star-gazers are unaware of it.

Before we get to the “where,” let’s kick around the “what.” To contemplate that gig, we’ll look at the basic shape of our little slice of the universe.

If we could look at our home galaxy, the Milky Way, from edge-on, we’d see that it’s shaped like a flying saucer. It’s basically disk-shaped with a bulge in the center. This is a common thing with a lot of galaxies, so it’s not like we’re special in this regard.

In a real flying saucer the center is filled with Martians along with their scientific gear so they can, of course, buzz around trailer parks and give people unsolicited probings. Our galaxy’s center bulge, by contrast, contains a dense core of stars, plus a giant black hole just to keep things interesting. The rest of the stars, including our sun, are basically spread out within the galactic disk.

Assuming the sky conditions are reasonably good, the Milky Way’s disk is easy to see; hey, we live in it, so it’s all around us. It’s the bright, wide band of starlight that goes across the night sky. This band is often called the “Milky Way,” but what people really mean is that it’s the disk, or plane, of the Milky Way. After all, with very few exceptions, anything and everything you see with the bare eye is actually within the Milky Way galaxy.

Anyway, if we look away from the plane by 90 degrees, we’re looking in a polar direction. If we look “up,” this direction is called the north galactic pole. If we look “down,” this direction is the south galactic pole. So these are just imaginary lines in space. Incidentally, I believe that the sun is the galactic reference point for these lines, but this isn’t a detail that a slob like me has to heed.

When these imaginary lines are extended to the geometric realities of how we view the heavens, the poles can be plotted as points on a chart. They are fixed points on the charts, just as the stars are, but from Earth’s perspective all this stuff is constantly moving relative to us.

This time of year, the north galactic pole isn’t visible from Saipan. But the south galactic pole is. Unfortunately, nature has not seen fit to endow this line of sight with any bright stars, so it’s as empty as a gas tank before payday.

I tried to concoct an easy, beach chair way to find the south galactic pole from Saipan tonight, though it’s likely that clouds will be in the way. But I’ll mention my idea anyway. As a landmark, or I guess I should say skymark, the moon is easy to see, so we’ll use that. And as a measurer we’ll keep in mind that a fist, at arm’s length, covers 10 degrees of arc. Here’s what I came up with:

At 11pm tonight, from Saipan, the moon will be hanging roughly 50 degrees (five fists) over the eastern horizon. If you look at the moon, and slide your gaze 80 degrees to your right (which will be toward the south), maintaining the five-fist altitude over the horizon, you’ll be looking at the south galactic pole. Or at least you’ll be close enough to it to win a cigar if anyone took up the wager. And that’s all you’ll win, since, like I said, to the bare eyeball, there’s nothing there.

But for folks who point optics at the sky, there is a very juicy sight nearby. It’s one of the brightest galaxies in the sky. This is called (take your pick) the Silver Dollar Galaxy, the Sculptor Galaxy, or the more nerdy-sounding NGC 253. It was discovered by Caroline Herschel in 1783.

If you do a Web search for that galaxy you’ll uncover a lot of good pictures. It’s a very lively galaxy, called a “star burst,” and it’s something of a celestial maternity ward, brimming with hot blue stars that were just born. The blue from those stars is clearly visible on the photos.

Well, that concludes this armchair tour. You are now returned to your earthly concerns, including typhoons, Ebola, and the usual swirling currents of human consternation.

Gee, with all that to contend with, maybe the galactic south pole isn’t so bad after all.