Last night, I saw something pretty amazing.
It rose very slowly from the horizon, in the north and slightly to the west. It had a sort of red tint to it, and as it rose, it got brighter and unmistakably faster. Jupiter was behind us as a convenient point of reference, and this thing was easily as bright as Jupiter before the whole thing was over. By the time it was directly overhead, it seemed impossibly fast for something so small and distant. It was completely silent. As it soared over us, it dimmed slightly, and then it suddenly vanished. It was just gone. It had taken less than four minutes from the moment we saw it lift slowly from the horizon to the moment it vanished.
Except that it wasn’t a UFO.
The International Space Station orbits the Earth often enough that sometimes it lines up just right for a spectacular show. Last night, shortly after sunset in Los Angeles, was one such show. The trick is that it has to bounce light from the sun to be visible, but the ambient light where you’re standing has to be low enough for it to stand out. During the day, there’s too much light in the sky to see it pass overhead. During the night, there’s no light bouncing off the ISS to illuminate it. So there’s a thin rare threshold of twilight for this show.
When we saw the ISS last night, as it rose from the horizon into the night sky, it was still in sunlight even though we weren’t. And as it passed overhead, we could see more of its reflective surface, so it appeared to get brighter much as the way the moon gets brighter as it turns more of its illuminated face to you. And when the ISS suddenly vanished while it was still overhead, it was simply passing into the Earth’s shadow.
It was one of the coolest things I’ve ever seen in the sky. If I’d simply glanced up, I would have taken it for an airplane and thought nothing of it. But if I’d been lounging around watching the sky for no good reason, I might have been one of the many people convinced he’d just seen a flying saucer. Instead, a few of us were goofing around playing Too Human and Soul Calibur IV when the phone rang. It was my next-door neighbor, who works at JPL and knows this kind of stuff.
“You guys want to see the International Space Station?” he’d asked. So we went next door and stood in his dark driveway. He pointed to a spot on the horizon and prophesied exactly what would happen, where it would happen, and when it would happen. We watched it happen and felt like little kids again under the quiet spectacle of the night sky.
-Tom