With data collected from the W. M. Keck Observatory, California Institute of Technology (Caltech) astronomer Mike Brown — known as the Pluto killer for discovering a Kuiper-belt object that led to the demotion of Pluto from planetary status — and Kevin Hand from the Jet Propulsion Laboratory (JPL) have found the strongest evidence yet that salty water from the vast liquid ocean beneath Europa’s frozen exterior actually makes its way to the surface.
The data suggests there is a chemical exchange between the ocean and surface, making the ocean a richer chemical environment, and implies that learning more about the ocean could be as simple as analyzing the moon’s surface. The work is described in a paper that has been accepted for publication in the Astronomical Journal.
The findings were derived from spectroscopy delivered from the Keck Observatory, which operates the largest and most scientifically productive telescopes on Earth.
“We now have the best spectrum of this thing in the world,” Brown says. “Nobody knew there was this little dip in the spectrum because no one had the resolution to zoom in on it before.”
It was another hike out to see the lava. Not that I really need an excuse to make this hike. This time it was to take a friend along. I have worked with Olivier for several years, between the two of us we do much of the physical maintenance on the Keck adaptive optics systems. Shortly he will be departing the island for another opportunity. Before he leaves he wanted to cross off one more item from his bucket list, seeing the lava close up.
The ocean entry at KupapaʻuUnlike last time we found the ocean entry was going strong, lava pouring into the sea very near where we saw nothing in December. There were multiple small entries spread along hundreds of yards of sea cliffs. On the west end of a shallow bay, we could get a decent look from promontories on the east end, upwind of the acrid plumes. Right below us was one particularly good font of lava, in reach of a modest telephoto lens.
It was still completely dark, the light of the full moon masked by the clouds. The waves were lit by the crimson glow, occasionally surging against the cliffs and hiding the lava from view. The glow also illuminated the billowing clouds of steam rising above each rivulet of lava. The scene is surreal, something that is both unexpected and somewhat difficult to believe. This is something that is outside our usual daily experience.
An active pāhoehoe breakout at KupapaʻuAfter spending some time at the ocean entry we searched inland for a breakout we could approach more closely. A slight glow to the north indicated a possible breakout, but I had no idea if it was close or miles away. With hope we headed for the glow and got lucky. It was only about a quarter mile to the breakouts. Several lobes of lava were advancing over the slightly older flows. Dropping our gear well back from the active lava cameras were deployed. This is what we came to see and photograph, lava as close as the heat would let us get.
Olivier hiking over the lava at KupapaʻuFor two hours we shot the breakouts. As usual, the flow would crust over, just to break out and advance again. The changing flow would provide ever different photo opportunities as the light of dawn slowly waxed. It was a cloudy day, small showers moving through, softening the dawn light and making the hot glow stand out all the more. The photos and video capture the scene, but do poor justice to the sound. The crackle of the cooling crust, raindrops hissing on the hot surface, low resounding cracks from deep in the rock under our feet.
With the day well begun we headed back to the ocean entry to shoot a few more frames in the early light. We sat on rock that was fairly warm under us, shooting the lava pouring into the waves. Relaxing a bit, digging a few bites to eat from the pack, we talked of cameras and lenses, of life on the island, a last bit of camaraderie with someone I might never meet again. We sat and just enjoyed this spectacle of raw nature. This was why we came, there is some risk in just being here, but the experience is worth it.
