Astronomers using the Hubble Space Telescope have found evidence of a thin oxygen atmosphere on Jupiter's moon Ganymede, the largest of the Jovian satellites. The same team of scientists previously had found a tenuous veil of oxygen around another Jupiter moon, Europa. The observations also suggest that Ganymede, like Earth and Jupiter itself, has polar aurorae -- light displays created when charged particles collide with atmospheric gases.
A team of astronomers used the Hubble ...