On Monday, NASA held a press teleconference with four people to announce the second possible detection of water on Europa, one of Jupiter’s moons, by NASA’s Hubble Space Telescope (HST). Britney Schmidt, assistant professor in the School of Earth and Atmospheric Sciences was one of the panelists, acting as an outside expert. She played no role in the discovery.
Schmidt is one of Europa’s leading experts. Many think the moon is the best chance to find other life in the solar system, primarily because of its subsurface ocean.
This isn’t the first time we’ve “seen” plumes on Europa. HST data also showed what appeared to be plumes of water vapor shooting about 120 miles from Europa’s surface in December 2012. This detection looks like the same thing, but from a different area. All of the detections to date are just above the noise, making these results exciting but requiring further work to confirm.
If these plumes are real, it’s unlikely to be a direct topping of the ocean — Europa’s ice is really thick. Despite many fractures, the tides just don’t seem strong enough to break all the way through the ice. Instead, there’s a lot of geology that could create water-filled plumes, including ridges or chaos regions (hilly areas of broken ice formed by melting and breaking up the surface). Despite all the ice, evidence suggests liquid water is near Europa’s surface. Today’s announcement increases that likelihood.
HST’s Imaging Spectrograph, or STIS, was used to detect these latest plumes. It’s a tough instrument to use because the technology is complex and the instrument is pretty old. So for it to detect a plume probably means it must be huge. That’s not very surprising – plumes would have to be big for us to see them from near Earth. But it’s impactful.
NASA is in the planning and building process for a spacecraft scheduled to launch to Europa in the early 2020s. I’m a member of one of the instrument teams. Today’s announcement just builds the excitement for the Europa Mission, which will make many flybys of Europa late in the next decade. If the plumes are real, it means we may not have to land on Europa to sample its water. And that’s really exciting.
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