(CN) – While Jupiter’s moon Europa has been considered one of the most likely places in our solar system to have alien life, a discovery announced by NASA on Monday raises the likelihood that it could house extraterrestrial microbes.
Using NASA’s Hubble Space Telescope, a team of astronomers saw what may be water vapor plumes erupting from the surface of Europa into space. This finding also suggests that missions to Europa may be able to sample the moon’s ocean without having to drill through miles of ice.
“Europa’s ocean is considered to be one of the most promising places that could potentially harbor life in the solar system,” said Geoff Yoder, acting associate administrator for NASA’s Science Missions Directorate. “These plumes, if they do indeed exist, may provide another way to sample Europa’s subsurface.”
The findings were presented during a teleconference with reporters, during which the team explained that astronomers believe the plumes rise about 125 miles before raining material back onto Europa’s surface. The team observed the projections while viewing Europa’s limb as the moon passed in front of Jupiter.
While the astronomers’ original goal was to determine whether the moon has a thin extended atmosphere, the team realized the same tools could be used to determine if there was water vapor venting from Europa’s surface.
“The atmosphere of an extrasolar planet blocks some of the starlight that is behind it,” lead astronomer William 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.”
In 10 separate instances over 15 months, the team observed Europa passing in front of Jupiter. The astronomers saw what may be plumes erupting on three of these occasions.
Their findings support evidence for water plumes on the moon that were initially detected in 2012 by Lorenz Roth of Southwest Research Institute in San Antonio, Texas. Roth found evidence of water vapor erupting from the icy south polar region of Europa that reach more than 100 miles into space.
While both teams used NASA’s Space Telescope Imaging Spectrograph instrument, they used completely different methods to arrive at the same conclusions.
“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 and his team found,” 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.”
However, the teams have not detected the plumes simultaneously using their independent techniques. Initial observations suggest the plumes could be highly variable, meaning they might erupt for a period of time and then die down indefinitely. Observations by Roth’s team done within a week of one of the detections by Sparks’ team failed to detect any plumes.
If the new findings are confirmed, Europa would be the second moon in the solar system known to have water vapor plumes: In 2005, NASA’s Cassini orbiter detected jets of water vapor and dust spewing off the surface of Saturn’s moon Enceladus.
Paul Hertz, director of NASA’s Astrophysics Division, highlighted Hubble’s continuing role in significant astronomical discoveries.
“Hubble’s unique capabilities enabled it to capture these plumes, once again demonstrating Hubble’s ability to make observations it was never designed to make,” Hertz said. “This observation opens up a world of possibilities, and we look forward to future missions – such as the James Webb Space Telescope – to follow up on this exciting discovery.”
Photo: NASA/ESA/W. Sparks
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