The Helix Nebula is an example of what astronomers call planetary nebulas, a nod to their orblike shape, as seen in early telescopes. But the appearance of planetary nebulas has little to do with planets at all—these nebulas are actually roiling clouds of hot gas that emanate from dying sunlike stars and linger after their deaths. These echoes do still have a “planetary” connection because their wafting clouds of gas and dust serve as the raw material for new generations of stars and planets.