The Hubble Space Telescope has captured on image what might be water vapor trails venting off Europa’s surface. Europa is the sixth-nearest satellite of Jupiter and the tiniest of its 4 Galilean moons.
Sci-News has reported that Europa holds a global ocean
bearing twice as much as on Earth’s, but it is sheltered by a thick layer of extremely hard and cold ice. How thick it is, nobody knows yet.
The said ‘plumes’ shows an enticing chance to gather samples on what is coining from under its surface without the need to touch ground or drill through ice.
“Europa’s ocean is considered to be one of the most promising places that could potentially harbor life in the Solar System. These plumes, if they do indeed exist, may provide another way to sample Europa’s subsurface,” said Dr. Geoff Yoder, of NASA’s Science Mission Directorate.
The plumes are estimated to rise about 125 miles (200 km) before, presumably, raining material back down onto Europa’s surface.
A team of scientists headed by Dr. William Sparks of Space Telescope Science Institute noticed finger-like ridges while viewing Europa’s branch as the satellite routes in front of Jupiter.
The original intention of the team’s observation proposal was to find out whether Europa has a thin, extended exosphere or atmosphere. By using exactly the same method that determines atmospheres around planets from other stars, the scientists then realized if water vapor was erupting out from Europa’s surface. An excellent observation if proven true.
“The atmosphere of an extrasolar planet blocks some of the starlight that is behind it,” Dr. Sparks said.
“If there is a thin atmosphere around Europa, it has the potential to block some of the light of Jupiter, and we could see it as a silhouette.”
“And so we were looking for absorption features around the limb of Europa as it transited the smooth face of Jupiter.”
The researchers also observed 10 transits of Europa passing across Jupiter over 365 days. They observed what could be trails erupting on 3 of these occasions.
About 4 years ago, Dr. Lorenz Roth of the University of Cologne and the Southwest Research Institute, together with co-authors noticed evidence of water vapor coming out from the southern polar region of Europa, reaching 100 mi or more (160 km) into space.
Though both teams used the Imaging Spectrograph of the Hubble Space Telescope, each instance used a completely independent technique but still arrived to the same conclusion.
“When we calculate in a completely different way the amount of material that would be needed to create these absorption features, it’s pretty similar to what Roth et al
found,” Dr. Sparks said.
“The estimates for the mass are similar, the estimates for the height of the plumes are similar. The latitude of two of the plume candidates we see corresponds to their earlier work.”
But as of this writing, the teams have not detected in unison the suspected plumes with their individual methods. Observation therefore suggests the said plums could just be highly variable, which means that they just sporadically burst for a short period of time then die down.
When confirmed, Europa will be the 2nd
moon in the Solar System discovered to have water vapor streaks. Back in 2005, Cassini detected dust and water vapor jets spitting off the surface of Enceladus
, one of Saturn’s moons.
The team’s findings will be released in the Sept 29 issue of the Astrophysical Journal
Source | Sci-News