Short answers, pulled from the story.
William Herschel spotted Enceladus on the 28th of August 1789 while using his forty-foot telescope at Observatory House in Slough. The moon appeared with an apparent magnitude of plus eleven point seven making it nearly invisible against Saturn's glare.
Gravimetric data from Cassini flybys revealed a liquid water ocean extending about fifty kilometers deep at the south pole. This global ocean lies beneath an ice shelf roughly thirty kilometers thick and implies the entire icy crust is detached from the rocky core below.
Enceladus serves as the primary source for Saturn's diffuse E ring through continuous venting activity that ejects water vapour and ice particles into space. These particles replenish the ring which has a lifespan ranging from ten thousand to one million years without constant addition.
Scientists detected molecular hydrogen organic molecules including benzene phosphates and hydrogen cyanide within the plumes ejected from the south polar region. These compounds complete the list of basic chemical ingredients required for life as we know it and suggest hydrothermal activity on the ocean floor.
Voyager 1 flew past Enceladus on the twelfth of November nineteen eighty at a distance of two hundred two thousand kilometers. Images from this mission revealed a youthful surface devoid of impact craters despite the moon's small size.