Io, Jupiter

Skywatchers on Thursday evening, Feb. 6, will notice an eye-catching pairing-off between two of the brightest objects in the nighttime sky. The moon, nearly two nights past first quarter and appearing ...
Jupiter’s moon Io is the most volcanically active world in the Solar System. The gravitational tug-of-war between Jupiter and its other large moons squeezes Io so that its interior is ...