Milky Way Intimacy Part 1

Lauren Hollen and I recently helped Tehachapi High School rap up their academic year by giving a short talk to all of their ninth graders on optics and telescopes.

Lauren started things off by saying, in her infectiously animated style, “I’m sure you’re all excited that summer is right around the corner. So am I! -- but probably for a different reason: The Milky Way is approaching its best position for evening viewing, and the weather is becoming more cooperative.”

The thing that captivated me was her ability to stimulate that sense of wonder that all of us children are born with. Since that’s the primary goal of my column, let me give it a try.

A long time ago, in a desert far, far, away... It was a moonless night as I was screaming down I-15 on the way to Las Vegas in our blue Millennium Pinto. My new bride, a lifelong Los Angelina, was clueless as to my intentions when I turned off onto Zyzzyx Road. I had to drive a good five miles before even the lights of the freeway were out of sight. I stopped the car and turned off the engine. My beloved turned to me and said, “I trust you with my life, but what the hell are we going to do out here!?”

“I’m going to show you the Galaxy like you’ve never seen it before!” OK, this is the sort of thing she’d come to expect from me -- strange, but not kinky.

We sat for a couple of minutes to let our eyes adjust to the darkness sans headlights as I briefed her about opening and closing the doors with her eyes closed. Soon we were both out with our eyes turned toward the heavens. As expected, the Milky Way was arched high overhead, resplendent with its dust clouds and star clusters.

My meditative reverie was shattered as white light flooded my vision. She had opened her car door and said, “I can’t handle this!” The car door slammed shut and she was safely back inside. Being a true Valley Girl, never in her life had she been in such darkness. The wonder of the Galaxy actually took her breath away! (To be sure, she’s grown a very great deal since then.)

To really get the best views of our galaxy, you need to get away from the city lights. (Yes, I’m talking about the City of Tehachapi. Kern County has a Dark Sky Ordinance, but the City of Tehachapi still resists the idea.) Fortunately, it’s still possible to do so, although it’s important to stay clear of the prison, as well. You also need to let your eyes adjust to the darkness, preferably for a good twenty minutes.

Casually looking at the Milky Way is actually rather bewildering. It’s as if we’re sitting on a raisin embedded in a cinnamon roll trying to make sense of the overlapping and obscuring layers of bright and dark stuff that make up our region of the galaxy. Many of us amateur astronomers have learned about the various nebulae and star clusters that populate the galactic expanses. However, translating that into a coherent picture of our place in the Galaxy is a daunting task for mere human brains.

That is until Craig Crossen, a former Minnesotan now living in Vienna (it sounds like he traded up!) began publishing a series of articles in Sky & Telescope magazine on “Observing the Milky Way.” Over the course of the past year, he has taken us on a step-by-step tour of the entire Milky Way, providing depth and insight I’ve never seen before. Constellation by constellation and layer by layer, he unwraps the giant cinnamon roll to reveal our galaxy in three dimensions. Let me tell you just a little bit about a particularly rich part of the galaxy that I’ve enjoyed becoming intimate with, which is now rising into our evening southern sky.

The center of our galaxy lies in the constellation Sagittarius, the archer (or the teapot, if you like). At the actual center lies a supermassive black hole surrounded by a huge maelstrom of stars, and swirling dust and gas called the central bulge.

At a distance of some 27,000 light-years, there’s an awful lot of stuff between here and there. And yet, there are actually holes through which we can peer quite deeply into the inner reaches of the galaxy. The Great Sagittarius Star Cloud, the “steam” coming out the teapot, is a window that allows us to see the central bulge with the unaided eye at a distance of at least 20,000 light-years! Binoculars can even momentarily resolve some of its brightest stars. And to think that the light from those stars left when humanity was still struggling to keep the campfires burning....

To the right of Sagittarius is Scorpius (no, not Scorpio; that’s astrology!). At the point where its tail begins to curve is a knot of faint stars known as NGC 6231. It is the centerpiece of a larger group known as the Scorpius OB1 Association, “one of the richest concentrations of extremely hot and luminous O-type giants and supergiants known in our galaxy.” It’s one of the most stunning binocular sights. As Americans, we’re lucky to live far enough south to be able to see these stars.

Next month I’ll tell you how the Scorpius OB1 Association can help you identify the different spiral arms of the galaxy.

As the weather continues to heat up, you’ll be pleased to know that on July third, the earth is at its farthest point from the sun. This helps moderate our summers. Conversely, we are closest to the sun in December, thus moderating our winters. Also conversely, the Southern Hemisphere gets hammered on both counts; they’re closest to the sun in their summer and farthest from the sun in their winter. It’s good to live in the North!

While Jupiter still blazes in the west at sundown in early July, it will soon be lost in the sun’s glare, reaching conjunction on the 24th. Mars is still riding high, but will start setting before midnight by month’s end. Saturn takes its turn as the all-nighter, rising at dusk and setting at dawn. With its rings tilted a good 21 degrees, Saturn is a delight for small telescopes. Venus is bright in our morning sky and will be joined by much fainter Mercury to its lower left as July progresses.

Sunrise: 5:45 a.m./Sunset: 8:11 p.m. (July 5)