The Center of the Galaxy

By Bob Berman|Wednesday, July 01, 1992
Each summer the thousands of stars visible in rural skies take a backseat to the dramatic mottled band that dominates the scene. That band is our own galaxy, the Milky Way, regarded by some earlier cultures as the centerpiece of the heavens.

They were right. For as it cascades downward toward the southern horizon it suddenly sports an extra-luminous section, like a splotch of spilled cream. And this glow is nothing less than the center of the galaxy.

Well, almost the center--what this glow really marks is the direction of the galactic core. We can peer barely 10 percent of the distance to the actual center before a profusion of stars and dust obscures the crowded turbulence beyond. But radio and X-ray emissions have confirmed that the black heart of our galaxy is right there, 30,000 light-years away, just beyond Sagittarius, whose stars resemble an archer only to those with gifted imaginations. Sagittarius actually looks like a teapot and is often labeled that way on today’s charts. Steam--really a wash of light-- appears above the teapot’s spout, and it’s this misty glow that marks the galaxy’s center.

Still, what we can see of the Milky Way makes it a showcase of the summer sky. Many astronomy aficionados wait until around midnight or so, when the galaxy’s center is at its highest. At that hour the Milky Way boldly bisects the sky from north to south. The galactic nucleus, fairly low and due south, grabs attention in inverse proportion to the sky’s pollution. In country darkness, particularly in southerly climes where it’s higher up, the intriguing glow of this road to heaven, as some ancients called it, pleads for hands-on exploration.

The ultimate view may be had through the giant quarter-ton binoculars used by some Japanese zealots but rarely seen in the West. Fabulous views also materialize in ordinary telescopes, especially those with wide-field eyepieces. With larger six- and eight-inch apertures now common, thousands of amateurs routinely experience the majestic star clusters and nebulous ribbons of twisted dust and gas that float like ghosts near the galaxy’s center. Here and there, ink black streaks interrupt the glow. These colossal dust clouds add the third dimension: they lie somewhere behind the night’s stars but in front of the Milky Way’s dreamy backdrop.

Even the sun, moon, and all the planets periodically get into the act, since, by coincidence, the plane of our solar system passes that way. The sun faithfully marks the galaxy’s center each mid-December when it enters Sagittarius. The moon floats just above the spot on July 12 and again on August 8 this year, targeting the area even while cloaking it with unwelcome brightness.

You don’t really need any fancy optical instruments to appreciate this bit of cosmic splendor. Ordinary binoculars will more than suffice. Indeed, you might just spend a moment simply staring. After all, a trillion suns pay it homage: every star of every constellation revolves around that spot of the sky. The sun’s grand circuit of the galactic center, with Earth tagging along, is sometimes called a galactic year. Perhaps a watch company with faith in its product will someday include a galactic-year hand that completes one sweep every 250 million years, to tell us where we stand.

Until then, we’ll have to step outdoors some warm summer evening and settle for the real thing.
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