Zachory Berta-Thompson

The three planets in the Kepler-51 system have long intrigued astronomers: they are Saturn-sized but less dense than water. These 'super-puff' worlds, with masses no more than ten Earths, are like cosmic dandelions — massive yet almost weightless. Their orbits are arranged like musicians in an orchestra, each playing its part, beating the rhythm with transits.

Astronomers caught the young planet AU Mic b in the act of hiding behind its star. The Spitzer telescope tracked its infrared glow: as the planet slipped behind, the system's total light dimmed slightly. The dip was just 171 parts per million, like a single drop of ink in ten buckets of water.