Jimmy Westlake: See the magnificent Milky Way
July 7, 2017
"Faint and misty, soft as silk,
Some say you are made of milk.
Road to heaven, river of light,
Glowing star clouds fill the night."
[Jimmy Westlake, 2010]
When the full Thunder Moon leaves the evening sky next week, the dark summer night will reveal one of its most spectacular treasures — the soft, misty glow of the Via Lactea, or the Milky Way.
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Contrary to what the ancient Romans believed, the Milky Way is not made from the milk of the queen goddess Juno. The Milky Way is our home galaxy, a swirling collection of hundreds of billions of stars that are more or less like our sun. If you look through a pair of binoculars and sweep slowly across the hazy Milky Way, you will rediscover what Galileo did way back in 1610 — the haze is a multitude of faint stars.
The situation is analogous to soaring high over a sandy beach and seeing the white sand stretch for miles in both directions and, yet, you cannot see the individual sand grains that make up the beach from that height. In the case of the Milky Way, the grains of sand are the myriad stars that populate our galaxy.
The sun is but one grain of sand on this cosmic beach. Think about that as you dump a million sand grains out of your shoe on your next visit to the seashore.
The word "galaxy" literally means "milk," from the Greek word "galax." Because it is flattened like a pancake, and we peer outward from inside that pancake, we see the Milky Way's arms wrapped gently around us in a narrow band that runs almost north to south on summer evenings. Our view of the Milky Way is from a location about two-thirds of the way out from the center to the edge, out in the galactic suburbs.
One of the brightest star clouds of the Milky Way is seen just above the spout of the Teapot asterism in the constellation Sagittarius, hanging low in our southern sky around 11 p.m. this month. When we peer off into this direction, we are looking directly toward the center of the Milky Way galaxy, some 28,000 light years away.
We cannot view the center directly because of the intervening stars, gas and dust, but there is mounting evidence that a supermassive black hole lurks there. This behemoth tips the scale at 4 million times the mass of the sun and has a gravity so powerful that its own light cannot escape its grip. Astronomers are struggling with the chicken/egg question of which came first, the Milky Way galaxy or the monster black hole that lies at its core?
Experiencing the subtle beauty of the Milky Way has become a privilege that many Americans might never have. A large majority of our nation's population lives in or near a large city where human light pollution drowns out this natural wonder. To them, the Milky Way is something that you see pictures of in a book or watch a poor projection of in a planetarium theater.
Streetlights and spotlights aimed skyward scatter so much unnecessary light into the night sky that it overwhelms all but the brightest stars. Many cities are making efforts to curb this urban light pollution to preserve the beauty of the nighttime sky.
The International Dark-Sky Association, or IDA, is the only nonprofit organization fighting to preserve the night. For more information, you can check out their website at darksky.org.
For the time being, at least, here in northwestern Colorado, all we have to do is step out into our backyard to see the galaxy of which we are a part, the magnificent Milky Way.
You are invited to join me for a public Star Party out at the Yampa River State Park campground at 9:15 p.m. Saturday, July 15. We can view the Milky Way and the summer constellations together, and I'll have a couple of telescopes set up to view the planets Jupiter and Saturn. I might even bring along my guitar to sing a starry song or two while we stargaze.
The Yampa River Star Party is perfect for all ages, so bring the whole family. Colorado State Park officials remind us that a valid annual Colorado State Parks pass or daily pass is required on all vehicles. Daily passes will be available on site.
I would recommend bringing along a camp chair, some insect repellant, a small red-filtered flashlight and a warm jacket for the cool night air after sundown.
To get to the Yampa River State Park campground from Steamboat Springs, take U.S. Highway 40 west to Hayden. Continue on U.S. 40 another 3 miles past Hayden and turn left into the campground. From Craig, head east on U.S. 40 for 14 miles and turn right into the campground.
The Star Party will be held on the grassy lawn in front of the Visitor's Center. We'll start the stargazing at 9:15 p.m. I hope to see you there.
Jimmy Westlake recently retired from Colorado Mountain College, after nineteen years as their Professor of Physical Sciences, and is looking forward to spending a lot more time under the starry sky. His “Celestial News” column appears in the Steamboat Today newspaper the first Friday of every month. Check out Jimmy's astrophotography website at http://www.jwestlake.com.