Composite Hubble Space Telescope image of water plumes (white, bottom left) erupting from the surface of Jupiter's moon Europa. The plumes rise about 200 kilometres from the moon's surface and can be seen as it travels in front of Jupiter. Europa's surface is thought to consist of an ocean of liquid water covered by a thick layer of ice. The presence of liquid water allows for the possibility of life developing on Europa. The plumes provide an opportunity for Europa's water to be sampled for life without the need to land on the moon and drill through its ice. This image of Europa, superimposed on data from Hubble's Imaging Spectrograph, is assembled from data from the Galileo and Voyager missions. Hubble data collected on 26 January 2014.