A familiar ingredient has been hiding in plain sight on the surface of Jupiter's moon Europa. Using a visible-light spectral analysis, planetary scientists at Caltech and NASA's Jet Propulsion Laboratory in Pasadena, California, have discovered that the yellow color visible on portions of the surface of Europa is actually sodium chloride, a compound known on Earth as table salt, which is also the principal component of sea salt.
Between the Europa Clipper and the proposed Europa Lander, NASA has made it clear that it intends to send a mission to this icy moon of Jupiter in the coming decade. Ever since the Voyager 1 and 2 probes conducted their historic flybys of the moon in 1973 and 1974 – which offered the first indications of a warm-water ocean – scientists have been eager to peak beneath the surface and see what lies within.
In 1610, Galileo Galilei became the first astronomer to discover the large moons of Jupiter, using a telescope of his own design. At time passed, these moons – Io, Europa, Ganymede and Callisto – would collectively come to be referred to as the Galilean Moons, in honor of their discoverer. And with the birth of the space exploration, what we’ve come to know about these satellites has fascinated and inspired us.