You’ll never see the universe as beautifully as the Chandra Observatory can see it. That’s because Chandra—which is celebrating its 15th anniversary in high-Earth orbit—sees in x-ray frequencies and you don’t. It’s a pity, actually that we’re blind in that bandwidth, because so much of the cosmos makes itself known there. Signals coming from planets, comets, supernovas, from the dark matter in the vast spaces between galaxies, all emit x-ray energy. The portraits they paint, with false color added to make them visible to our eyes, are more than static snapshots. They are, instead, pictures of processes: of matter spinning down the eternal drain of the black hole at the center of our galaxy; of galaxies colliding and merging; of the cool gas swirling at the center of the Andromeda galaxy.
Chandra records all of these cosmic processes—bits of history really, since at their great distances many of them played out in the remote past. In its own short life, it has crossed many boundaries in terrestrial history too. The satellite was lofted by the shuttle Columbia in 1999—a ship that was destined for catastrophe just four years later. It left Earth at a time when the World Trade Towers stood; when Barack Obama was an Illinois State Senator, one year away from losing his bid for a seat in the U.S. House of Representatives; when no one had ever heard of an iPhone. That doesn't seem like much in a universe whose chapters play out in epochs, not mere years. But for a fragile machine from a fragile planet, 15 long years of exploratory work aren't bad—especially when the post cards it sends home are so improbably dazzling. —Jeffrey Kluger