Jupiter's icy moon Europa has been a target on the search for habitable planets; and the Hubble telescope recently picked up a strange phenomenon around the object.
Scientists believe Europa is hiding a vast liquid ocean beneath its frozen surface, new data shows the space object may also eject liquid off its surface, a Hubble news release reported. The jets are believed to shoot 500 million miles in the air.
"The discovery that water [vapor] is ejected near the [South Pole] strengthens Europa's position as the top candidate for potential habitability," lead author Lorenz Roth of the Southwest Research Institute, said. "However, we do not know yet if these plumes are connected to subsurface liquid water or not."
The discovery names Europa as the second moon in our solar system known to emit liquid plumes; the first time the phenomenon was seen was on Saturn's moon Enceladus in 2005.
Europa's plumes were first spotted by The Space Telescope Imaging Spectrograph (STIS), which picked up evidence of gentle ultraviolet light around the aurora on the moon's South Pole.
"We pushed Hubble to its limits to see this very faint emission," co-lead author and principal investigator of the Hubble observing campaign Joachim Saur of the University of Cologne, said. "Only after a particular camera on the Hubble Space Telescope had been repaired on the last servicing mission by the Space Shuttle did we gain the sensitivity to really search for these plumes."
One theory, proposed by Roth, suggests cracks in the moon's surface (linea) could be allowing the liquid to be shot into space. A similar phenomenon has been photographed in the past on Enceladus.
"Do the vents extend down to a subsurface ocean or are the ejecta simply from warmed ice caused by friction stresses near the surface?" Roth asked.
The team also noticed the jets varied in size based on the position of the moon's orbit; this phenomenon has also been observed on Enceladus. On Europa the vents are only believed to be present when the moon is farther from Jupiter.
"One explanation is that the long fractures in the ice crust experience more stress as gravitational tidal forces push and pull on the moon and so open vents at larger distances from Jupiter. The vents are narrowed or closed when at closest approach to the gas giant," the news release reported.
The team hopes to conduct future missions to determine the exact size and place of the linea and plumes.
