Want to see the kind of inspirational, star-filled panorama experienced in planetariums? Late September is the perfect time for that. Right now, we’re aimed toward the most concentrated part of the Milky Way Galaxy. How many stars are in the Milky Way? Let’s find out!
What is the Milky Way?
In case you didn’t know, the Milky Way is our home galaxy. It a “barred spiral” type of galaxy with giant spiral arms that make it look like a spinning pinwheel. It includes our solar system and Sun, which is located on a smaller spiral arm, about half the distance from the center of the galaxy to its outer edges. While we on Earth orbit the Sun, our solar system’s one-and-only star orbits the center of the Milky Way!
The name “Milky Way” describes our galaxy’s appearance from planet Earth: a hazy, milky band of light stretching across the night sky. No one knows where the name came from, though the ancient Greeks used the word “Galactos” to refer to milk; there is a Greek myth about the goddess Hera who sprayed milk across the sky. Ovid, a Roman poet, later wrote about the Milky Way in “The Metamorphoses” in 8 A.D.
How Many Stars are in the Milky Way?
It’s estimated that there are several billion stars in the Milky Way Galaxy. All the stars you see from Earth are part of our home galaxy. However, how many stars you can see from Earth depends on the time of year!
Right now, in late September, we’re facing the highest concentration of stars. The Milky Way neatly splits the sky and passes directly overhead. The Moon is absent, so rural places away from city lights provide perfectly dark conditions, while September’s typical crisp, dry air affords the kind of transparency that allows the countless subtle details of the Milky Way to emerge in all its glory.
It’s a far cry from the spring, when the Milky Way is almost coincident with the horizon and invisible. Then, the sky offers only a smattering of stars to see. Ever noticed this?
Best Time to See the Milky Way
From September to October: The Milky Way is visible in the evening.
Look between 8 and 10 P.M. in the evening, looking up and towards the south.
Go to a dark place with no lights. Frankly, with light pollution, the Milky Way is all but invisible. From non-light-polluted places, it’s a wonderland.
When you do get to see the Milky Way on a dark, moonless night and in its full splendor, it’s very hard not to be in complete awe. It’s humbling and, for many, spiritual. It feels like stepping back to an ancient cosmos before lights existed.
Lately, wide-angle photos of nighttime landscapes with the Milky Way filling the sky keep appearing on the internet. It’s as if starry glow of our galaxy’s edgewise portion has suddenly been discovered after a long absence. In truth, long exposures made with expensive equipment, and taken in areas with an inspirational foreground like from Arches National Park, are indeed gorgeous.
Image: Arches National Park. Credit: NPS/Chris Wonderly
However, some of us, like myself, whose house is in a state park where the nearest village has a population of 153, can get the experience by merely turning off the house lights and stepping into the backyard.
And now is the best time to do that.
Places to See the Milky Way Galaxy
In terms of place, you simply need dark skies! Drive out to the country one evening or on the weekend. With most of the world now living in cities, the full impact of the Milky Way often requires overnight camping at some very rural site. Usually, driving inland away from a city is your best bet. If you’re willing to travel, check out the best “Dark Sky” sites.
From a dark location, it takes about 20 minutes for human eyes to become fully sensitive to faint light. Away from the lights of town, lie on a blanket or lounge chair (reclining helps ease neck strain). You will witness the combined light of uncountable stars populating the dense, central hub of the Galaxy. These suns are so concentrated that you see billowing “clouds” of stars!
Looking toward the dark skies at the right time of year, the naked human eye should see a whitish glow stretching in a huge arc. This band has been visible in the heavens since Earth first formed. This glowing line of light is the center of our galaxy, as seen from one of its spiral arms where we are located. It’s because our eyes cannot distinguish the individual stars that make up the glowing band of light that it all appears “milky.”
But the Milky Way is not merely a glow crossing the sky. (That’s only our point of view from Earth. From above, it’s that enormous spiral which spans 100,000 light years.) It’s wonderfully ragged and splotched with a myriad of inky patches that are vast dust clouds in our Galaxy’s spiral arms. It’s dotted with bright and faint stars that make it alive with activity and sets it apart from other sections of the sky. It’s a vault where star clusters and nebulae and 30,000 additional faint stars spring into view for anyone slowly sweeping its path with ordinary binoculars.
This is the place where knowledge can safely be put aside.
Once your eyes adjust to the darkness, simply taking fifteen minutes to be alone with the Milky Way during these moonless nights, is rejuvenating. Here, knowing the stars or constellations is as unnecessary as naming each trout in a stream. The lunatic riot of stars tumbling downward toward the south and the twisted texture of the background glow surely belongs in our lives at least once a year.
But if you’d like to name something, well, that brightest star most perfectly overhead at nightfall is Vega. (But say and think “VEE-ga,” not “VAY-ga.”)
And low in the south where the Milky Way has a brightening and a bulge, that’s the center of our galaxy. It’s the amazing place around which every star, including our own Sun and its retinue of planets, revolve once every 225 million years.
To the ancient Peruvians and Mayans, the Milky Way was the center of the universe. And even in our Space Telescope age, it’s still the heart of ours—our resident galaxy, observed not from the outside but from our worms’-eye viewpoint within its pinwheel motif.
Video: Zooming in on the heart of the Milky Way
This video by the European Southern Observatory (ESO) starts with a broad view of the Milky Way. We then dive into the dusty central region to take a much closer look. There lurks a 4-million solar mass black hole, surrounded by a swarm of stars orbiting rapidly. We first see the stars in motion, thanks to 26 years of data from ESO’s telescopes. We then see an even closer view of one of the stars, known as S2, passing very close to the black hole in May 2018. The final part shows a simulation of the motions of the stars.