Blanets and Weird Worlds

Exoplanet discoveries have revealed a far broader range of worlds than our Solar System suggests, although current detection methods favor massive planets close to their stars. The known catalog includes hot Jupiters that can lose their atmospheres and leave dense rocky remnants; a pulsar companion thought to be a stripped stellar core of crystalline carbon; and ultra-hot Neptunes where metals may cloud the atmosphere and iron may fall as rain. Super-Earths and Hycean planets - worlds potentially covered by hydrogen oceans - could offer environments for life, though crushing pressures would produce unfamiliar forms of ice. Rogue planets may drift alone, cold and dark, while still retaining heat or moons.

The most outlandish possibility is a blanet: a planet formed in the outer accretion disk around a supermassive black hole. Such bodies might exceed 20 Earth masses, orbit for hundreds of thousands of years, and receive heat from the disk or even from the black hole’s blueshifted background radiation. Stars and ordinary planetary systems may also form in these disks. These ideas serve as a store of scientifically grounded settings for space opera, including a work in progress featuring a potentially habitable, spinning Earth-mass moon orbiting a Hycean planet. The discussion also invites further examples; an astronomer responding describes WISPIT 2, a young star system where two giant planets are directly imaged within a disk, one carving a gap and accreting interstellar hydrogen.