. Objects placed in orbit for the sole purpose of being seen from Earth.
In January a company called Rocket Lab secretly added an extra point of light to the night sky. Dubbed the Humanity Star, it was a faceted carbon-fiber sphere parked in low Earth orbit, designed to twinkle as it caught the sun’s rays, thus creating a “shared experience for everyone on the planet.”
Astronomers were not amused. Some saw it as a publicity stunt, confirming their worst fears about private spaceflight. What’s next, they fumed, billboards in space? (Two weeks later, Elon Musk’s SpaceX launched a Tesla Roadster into solar orbit.) Others called it vandalism. The epithet that stuck was space graffiti.
In truth, the Humanity Star posed no real threat to astronomy, and it soon fell out of orbit, as planned. But the image of a giant disco ball hung in the firmament—that icon of humanity at its silliest and most joyful—raised questions that won’t go away: Why are we indignant over