Space

December 13, 2013

Hubble Space Telescope sees evidence of water vapor venting off Jovian moon

nasa-hubble
NASA’s Hubble Space Telescope has observed water vapor above the frigid south polar region of Jupiter’s moon Europa, providing the first strong evidence of water plumes erupting off the moon’s surface.

Previous scientific findings from other sources already point to the existence of an ocean located under Europa’s icy crust. Researchers are not yet certain whether the detected water vapor is generated by water plumes erupting on the surface, but they are confident this is the most likely explanation.

Should further observations support the finding, it would make Europa the second moon in the solar system known to have water vapor plumes. The findings were published in the Thursday, Dec. 12, online issue of Science Express, and reported at the meeting of the American Geophysical Union in San Francisco.

“By far the simplest explanation for this water vapor is that it erupted from plumes on the surface of Europa,” said lead author Lorenz Roth of Southwest Research Institute in San Antonio. “If those plumes are connected with the subsurface water ocean we are confident exists under Europa’s crust, then this means that future investigations can directly investigate the chemical makeup of Europa’s potentially habitable environment without drilling through layers of ice. And that is tremendously exciting,”
In 2005, NASA’s Cassini orbiter detected jets of water vapor and dust spewing off the surface of Saturn’s moon Enceladus. Although ice and dust particles subsequently have been found in the Enceladus plumes, only water vapor gases have been measured at Europa so far.

Hubble spectroscopic observations provided the evidence for Europa plumes in December 2012. Time sampling of Europaís aurora emissions measured by Hubble’s imaging spectrograph enabled the researchers to distinguish between features created by charged particles from Jupiter’s magnetic bubble and plumes from Europaís surface, and to also rule out more exotic explanations such as serendipitously observing a rare meteorite impact.

The imaging spectrograph detected faint ultraviolet light from an aurora, powered by Jupiter’s intense magnetic field, near the moon’s south pole. Excited atomic oxygen and hydrogen produce a variable aurora glow and leave a telltale sign that they are products of water molecules being broken apart by electrons along magnetic field lines.

“We pushed Hubble to its limits to see this very faint emission. These could be stealth plumes, because they might be tenuous and difficult to observe in the visible light.” said Joachim Saur of the University of Cologne in Germany. Saur, who is principal investigator of the Hubble observation campaign, co-wrote the paper with Roth.

Roth suggested long cracks on Europa’s surface, known as lineae, might be venting water vapor into space. Cassini has seen similar fissures that host Enceladus’ jets.

Also like Enceladus, the Hubble team found the intensity of the plumes varies with Europa’s orbital position. Active jets have been seen only when Europa is farthest from Jupiter. But the researchers could not detect any sign of venting when Europa is closer to Jupiter.

One explanation for the variability is these lineae experience more stress as gravitational tidal forces push and pull on the moon and open vents at larger distances from Jupiter. The vents are narrowed or closed when the moon is closest to the gas giant planet.

“The apparent plume variability supports a key prediction that Europa should tidally flex by a significant amount if it has a subsurface ocean,” said Kurt Retherford, also of Southwest Research Institute.

Europa’s and Enceladus’ plumes have remarkably similar abundances of water vapor. Because Europa has roughly 12 times more gravitational pull than Enceladus, the vapor, whose temperature is measured at minus 40 degrees Celsius, does not escape into space as it does at Enceladus. Instead, it falls back onto the surface after reaching an altitude of 125 miles, according to the Hubble measurements. This could leave bright surface features near the moon’s south polar region, the researchers hypothesize.

“If confirmed, this new observation once again shows the power of the Hubble Space Telescope to explore and opens a new chapter in our search for potentially habitable environments in our solar system” said John Grunsfeld, an astronaut who participated in Hubble servicing missions and now serves as NASA’s associate administrator for science in Washington. “The effort and risk we took to upgrade and repair Hubble becomes all the more worthwhile when we learn about exciting discoveries like this one from Europa.”

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) conducts Hubble science operations. The Association of Universities for Research in Astronomy Inc. in Washington operates STScI for NASA.




All of this week's top headlines to your email every Friday.


 
 

 

Headlines November 26, 2014

News: When Hagel leaves, new SecDef faces big questions about the military’s future - President Obama’s new pick to run the Pentagon will face a dizzying set of challenges affecting the Defense Department’s mission, budget and culture. Who will be the next Secretary of Defense?- Following the Nov. 24 surprise announcement from the White House, the...
 
 

News Briefs November 26, 2014

Navy to decommission two more ships in Puget Sound The Navy recently decommissioned the guided missile frigate USS Ingraham at Everett, Wash. It will be towed to Bremerton and scrapped. The Daily Herald reports the Navy also plans to decommission another ship at the Everett homeport and also one stationed in Bremerton. Naval Station Everett...
 
 

NASA airborne campaigns tackle climate questions from Africa to Arctic

NASA photograph The DC-8 airborne laboratory is one of several NASA aircraft that will fly in support of five new investigations into how different aspects of the interconnected Earth system influence climate change. NASA photograph The DC-8 airborne laboratory is one of several NASA aircraft that will fly in support of five new investigations into...
 

 
Air Force photograph by Rick Goodfriend

16T Pitch Boom reactivated to support wind tunnel tests

Air Force photograph by Rick Goodfriend The Pitch Boom at the AEDC 16-foot transonic wind tunnel (16T) was recently reactivated. This model support system is used in conjunction with a roll mechanism to provide a combined pitch...
 
 

Northrop Grumman supports U.S. Air Force Minuteman missile test launch

Northrop Grumman recently supported the successful flight testing of the U.S. Air Force’s Minuteman III intercontinental ballistic missile weapon system. The operational flight test was conducted as part of the Air Force Global Strike Command’s Force Development Evaluation Program. This program demonstrates and supports assessment of the accuracy, availability and reliability of the...
 
 
army-detector

Scientists turn handheld JCAD into a dual-use chemical, explosives detector

Scientists at the U.S. Army Edgewood Chemical Biological Center at Aberdeen Proving Ground, Md., proved it is possible to teach an old dog new tricks by adding the ability to detect explosive materials to the Joint Chemical Age...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>