Planned launch of 500,000 satellites could spoil about one in three Hubble images, even when the telescope stays above Earth's weather.

NASA's Hubble Space Telescope and an ESA orbiter bound for Jupiter both recently glimpsed 3I/ATLAS. The comet will make its closest approach to Earth in December but poses no threat and is not visible ...

Astronomers tracking a nearby star system thought they had spotted an exoplanet reflecting light from its star. Then it vanished. Even stranger, another bright object appeared nearby. After studying ...