A dazzling snapshot from ESO’s Paranal Observatory captures a rare sky parade — the Moon, a comet, and nearly every visible planet strung across the heavens. This celestial lineup is an optical ...

An international team used 40 years' worth of data from two space probes to track down what they believe are signs of this ...

Artist's illustration showing a distant star going out of sight as it is eclipsed by Uranus — an event known as a planetary stellar occultation. | Credit: NASA/Advanced Concepts Laboratory NASA ...

The decision came after scientists established three criteria for what defines a planet: it must orbit the sun, be spherical in shape and have “cleared” its orbital path of other debris.