Short answers, pulled from the story.
Galileo Galilei observed Europa on the 8th of January 1610 using a 20×-magnification refracting telescope at the University of Padua. He initially could not separate it from Io but saw them as distinct bodies on the following night.
Simon Marius named the moon after Europa, the Phoenician mother of King Minos of Crete and lover of Zeus. The naming scheme suggested by Johannes Kepler fell out of favor until general use revived in the mid-20th century.
Europa has an outer layer of water estimated to be around 100 km thick with a liquid ocean existing underneath the ice. Scientific consensus confirms this layer remains liquid due to heat generated by tidal flexing from Jupiter.
The surface temperature averages about -160°C at the equator and drops to only -220°C at the poles. These conditions keep Europa's icy crust as hard as granite despite internal geological activity.
NASA launched the Europa Clipper probe on the 14th of October 2024 aboard a Falcon Heavy rocket. Its aim is to explore Europa to investigate habitability and select sites for a future lander using instruments like ice-penetrating radar.