Discovery Alert: An Earth-sized World and Its Ultra-cool Star

The exoplanet SPECULOOS-3 b is about 55 light-years from Earth (really close when you consider the cosmic scale!) and nearly the same size. A year there, one orbit around the star, takes about 17 hours. The days and nights, though, may never end: The planet is thought to be tidally locked, so the same side, known as the dayside, always faces the star, like the Moon to Earth. The nightside would be locked in never-ending darkness.