Western Slope Skies: The Winter Milky Way
We humans like to know where we are. Feeling oriented feels good. Think of the confidence you gain once you’ve learned your way around in a new place. We are lucky to live under the still dark skies here on the Western Slope. We have the rare chance to see the Milky Way in all seasons. Getting to know our galaxy is just a bigger version of feeling at home in our neighborhood.
The name Milky Way means two things: the star-packed photogenic river of stars across sky for one. It also refers to the hundreds of billions of stars that make up our galaxy. No matter where you look in the Western Slope sky, every star is part of our galaxy.
The Milky Way galaxy is shaped like a flat disc with a bulge in the middle. Think simplistic octopus, with arms coming directly from the head. Our solar system is located about two-thirds of the way out from the center. The center, the octopus head, of the galaxy is thick with stars. If our sun was in the busy center, you’d see anywhere from 10 to 1000 times as many stars in our sky. Like our home in western Colorado, our planet exists in a rural solar system.
As our planet goes around its yearly orbit of the sun, the evening views into the surrounding Milky Way change. When we look up on a winter evening, we are looking away from the star-packed center. There’s a lot fewer stars in this direction, so the Milky Way stripe looks dimmer.
What about from the top? Astronomers classify our galaxy as a barred spiral. From above, our galaxy looks like an octopus twirling. Its long arms are partly wrapped around its head as they flow along behind. Our solar system lives in a short arm called the Orion Spur. The nearby arms are the Sagittarius Arm, which is closer to the center, and the Perseus Arm toward the outer edge.
Try looking toward the constellation of Orion in the southeast. The winter Milky Way is just to the left of Orion. The Gemini twins are next door, dipping their feet in that river. As you gaze at Orion, you are looking at the Orion Spur. Move your gaze up, and you are looking toward our outer neighboring arm, the Perseus Arm. Turn around and look northwest, at Cassiopeia, the giant M in the sky. Over here is more of the Perseus Arm as it wraps in toward the head of the octopus.
Traveling the Milky Way with a pair of binoculars is also a worthy journey. There are many interesting star clusters and nebulae large and small. Brace yourself against your car for steadier viewing.
As you wander our Milky Way neighborhood, savor this view as one reason we love our home. Most people in the world cannot see the Milky Way from where they live. But we are surrounded by International Dark Sky certified places, including Black Canyon of the Gunnison National Park, Curecanti National Recreation Area, and the towns of Ridgway and Norwood. As our community grows, let’s protect our stellar view as a special part of what makes this our home.
Western Slope Skies is produced by the Black Canyon Astronomical Society and KVNF Community Radio. This feature was written and voiced by park ranger Alice de Anguera.