The other night I was dragging the garbage can up to the curb, one of those routine chores I always enjoy because I always do it after dark and walk through patches of shadow where anything could be lurking which, now that I mention it, is starting to make me wonder why I enjoy doing it and why I don’t do it earlier when it’s still light out even though it’s better to do it late to make sure I’ve gotten as much trash as possible because if anything’s left over we’ll be stuck with it for a week. And I enjoy it because while I’m dragging the can I look up at the sky which is another thing I didn’t think about until just now: the contrast between the earthy, grimy, trash and the ethereal, seemingly eternal sky above me. Really I’m just looking for planes. Or at the clouds. Most of the time I see the stars. At this time of year the night is also noisy. Even in our suburban neighborhood the children of the night, what music they make. I mean mostly bugs and frogs, of course, since we don’t have any wolves, or at least I haven’t seen any, but the little critters of nature know that they’re noisy. And they’re noisy because even though it doesn’t feel like it yet the summer is coming to an end. Their biological clocks are winding down and there’s a special urgency, one last desperate chance to meet that special someone. They’re brooding on the need to make a new brood.
It’s really the stars I focus on, though. Last night at the edge of the street I looked up and even through the pale orange glare of the streetlight I could see three bright stars in a line. They were part of the constellation Sagittarius which might have been more visible if that streetlight hadn’t been there. Beyond Sagittarius, though, is the Milky Way.
Strictly speaking Sagittarius is part of the Milky Way, and so is Earth, which is why it confused me when I was a kid when people talked about seeing the Milky Way. We’re in it, albeit far out in one of the outer arms. If it really were an arm I think we’d be just past the wrist and our galaxy also has more arms than a Hindu deity. So I thought saying “I can see the Milky Way” would be like standing in your closet and saying “I can see my house”. It wasn’t until one night on a camping trip in an extremely remote area on a cool late summer night that I actually saw the Milky Way, the band of shining, stellar clouds that stretches across the sky. According to the ancient Greeks it was formed when baby Heracles suckled on Hera in her sleep and some of her milk spilled out across the sky—a myth that was meant to explain the origins of the breast pump, but that’s another story.
There was something strange about looking into it, knowing that even though I could only see a small part of it I was still looking into the very heart of our galaxy. How did astronomers feel when they first realized our sun is just another star, and a pretty puny one at that? How did they feel when they first realized we only see mere ghosts of stars, that interstellar distances are so vast it takes years, even centuries, sometimes millennia, for the light of stars to reach us? The ground under their feet must have seemed a lot less stable. And in my lifetime alone astronomers, working with geologists, have come to understand the Earth’s long history of being hit by big rocks on a disturbingly regular basis—one about every twenty-six million years. The idea that a nearby star might be throwing wild pitches was dismissed almost as quickly as it was proposed, but the regularity might not be a cosmic coincidence either. Our solar system doesn’t stay in one place. Even as the Milky Way slowly turns the regularity of mass extinctions may be the result of the way our solar system bobs and weaves in its arm, perhaps taking us sometimes into dangerous territory. And some people get a kick out of saying we’re overdo for an interplanetary sucker punch, but a million years is a really long time. It may not happen.
Closer to home is the issue of light pollution, the growing number of photons we’re spewing into the sky nightly that make it harder and harder to see features like the Milky Way and smaller, dimmer stellar neighbors. It’s a scary thought that the more lights we use to light the night here on Earth the more we lose a perspective on our place in the universe, as if we were standing in a closet with no way to know what lurks in the patches of shadow.