A Sun-like star burned out and became a white dwarf — a superheated ball the size of Earth, like a smoldering ember of a campfire. It is cooling but still warms its nearest neighbors. It is to this cooling hearth that a giant planet has drawn near.

When it passed in front of the fading disk, the James Webb Space Telescope at the moment of transit split its shadow into colors and through spectroscopy detected an atmosphere — thick, made of methane (rich in carbon) and clouds. But what's staggering is this: the planet spews out three times more heat than it receives from the dwarf. 130°C — not just heating from a campfire, it's its own internal burning.

The reason lies in its long journey. It migrated from a distant orbit, and tidal forces kneaded its interior like clay. Numerical simulations show that the journey took billions of years — which for stellar evolution is just yesterday. And methane here is the simplest organic building block; so even around dead suns, the chemistry of life is possible.