"In a second study, also in Nature, a team led by Nicholas Schneider of Colorado University likewise looked for salts in Enceladus' plumes, this time using spectrographs on Earth-bound telescopes.
That it failed to detect any would seem to challenge Postberg's findings, but the Earth-based observations -- combined with the Cassini data -- may in fact give us additional clues as to how they may be true, said Spencer.
It tells us, for example, that the plumes could not have been formed by boiling salty water spewing directly out of Enceladus' tiger stripes, otherwise the sodium would be so abundant as to be observable from Earth.
Instead, the plumes could come from salty water distilling into fresh water vapours, but not through evaporation as happens over Earth's oceans, but rather in pressurised chambers under the moon's surface."
Formed?
Tons of ice pellets hit the Earth every second, every day, and probably have since time began.
If they pelt the Earth, they pelt every astronomical body in space.