NASA is teasing big news about Europa. Next Monday, the space agency will hold a media call to discuss what they call “evidence of surprising activity on Europa.” Aliens, right? Pump the breaks. It’s not aliens.
— NASA (@NASA) September 21, 2016
But how do we know it’s not aliens? The new findings are coming from the Hubble Space Telescope. If it’s aliens, we might be screwed. If they’re big enough to be seen by Hubble, kill it with fire.
Next Monday’s news will center around the possible presence of a subsurface ocean on the moon. Scientists believe an ocean exists below Europa’s icy surface. The evidence is strong, but they haven’t been able to definitively confirm its existence yet.
Take what Hubble spotted in 2013 for example. Water vapor was spotted above the south polar region of Europa. Here’s what Lorenza Roth from the Southwest Research Institute said at the time:
“By far the simplest explanation for this water vapor is that it erupted from plumes on the surface of Europa. 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.”
Roth suggested the plumes of water vapor could be coming from the long cracks crisscrossing Europa’s surface.
Does an ocean lurk beneath Europa’s surface? Credit: NASA
But analysis of Cassini data in 2014 showed no evidence of water vapor plumes. (Note: Cassini orbits Saturn. The data analysis was from the 2001 Jupiter flyby before it reached Saturn) “We found no evidence for water near Europa, even though we have readily detected it as it erupts in the plumes of Europa,” said Larry Esposito at the time. Larry is the team leader for Cassini’s UVIS instrument.
Why the different observations between Hubble and Cassini? It could just be timing. Europa might not be exactly like Enceladus. Eruptions are constant in Enceladus’ south polar region. Europa’s possible eruptions might not be.
In fact, Hubble’s 2013 observations of water vapor point to it. The telescope only observed water vapor when Europa was at its furthest distance from Jupiter. Scientists believe it has to do with the gravitational tug from the much larger gas giant.
I’m putting money on Monday’s Europa announcement being about another detection of water vapor. It might not seem like much on the surface, but the news could have huge implications. Life as we know it only exists where there is the presence of water. Confirmation of an active subsurface ocean on Europa would shoot the small moon to the top of the exploration list.
NASA plans to launch a mission to Europa in the 2020s
NASA knows Europa is an intriguing target for further exploration. Confirmation of a subsurface ocean by the Hubble would only make it more so. And the space agency is already busy working on a spacecraft to explore the icy moon.
Expected to launch in the 2020s, the spacecraft will enter orbit around Jupiter and perform dozens of flybys of the icy moon. Does Europa have the right stuff for life to form? That’s what this orbiter will tell us.
Armed with a suite of instruments including ice penetrating radar, thermal instruments and more, the spacecraft will carefully study the surface of Europa over the course of 45 flybys. Altitudes will range from 1,700 miles to just 16 miles according to NASA.
Hubble might confirm the existence of water vapor next Monday, but it’ll be this spacecraft that cracks Europa’s icy shell and spills its secrets.
I’ll be covering Monday’s announcement and bring you the latest as we hear it.