The latest finding has given scientists fresh hope that a robotic spacecraft could one day fly past these potential plumes and learn about their contents without having to drill miles deep into the moon’s icy shell.
Using ultraviolet images taken by Hubble, a space telescope that was launched in 1990, the potential plumes were seen around the southern edge of Europa and appear as dark fingers or patches of possible absorption.
They were spotted over the course of 15 months in 2014 when scientists observed Europa passing in front of Jupiter.
This was observed by a team of astronomers led by William Sparks of the Space Telescope Science Institute (STScI) in Baltimore. They observed these finger-like projections while viewing Europa’s limb as the moon passed in front of Jupiter.
If 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.
About the Plumes on Europa
The plumes are estimated to rise about 125 miles (200 kilometers) before, presumably, raining material back down onto Europa’s surface.
Europa has a huge global ocean that contains twice water than Earth’s oceans, which is protected by a layer of extremely cold and hard ice of unknown thickness.
The plumes provide a tantalizing opportunity to gather samples originating from under the surface without having to land or drill through the ice.
Earlier in 2012, a team led by Lorenz Roth of the Southwest Research Institute in San Antonio, detected evidence of water vapor erupting from the frigid south polar region of Europa and reaching more than 100 miles (160 kilometers) into space. Although both teams used Hubble’s Space Telescope Imaging Spectrograph instrument, each used a totally independent method to arrive at the same conclusion.
Next step to confirm presence of water vapor plumes on Europa
It is expected that scientists will use the infrared vision of NASA’s James Webb Space Telescope, which is scheduled to launch in 2018, to confirm venting or plume activity on Europa. Besides, NASA is also formulating a mission to Europa with a payload that could confirm the presence of plumes and study them from close range during multiple flybys.
The work by Sparks and his colleagues will be published in the 29 September 2016 issue of the Astrophysical Journal.
Hubble Space Telescope
It is a project of international cooperation between NASA and ESA (the European Space Agency.) NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. STScI, which is operated for NASA by the Association of Universities for Research in Astronomy in Washington, conducts Hubble science operations.