Lois Ann Dort

Mission to watery Europa gains support

Chronicle Herald March 28, 2017

People of a certain age are familiar with Jupiter’s moon Europa. It had a starring role in Arthur C. Clarke’s Space Odyssey and made many a stargazer wonder if life on other planets was not just a science fiction dream but an actual reality. A reality that would not require light years and millennia to discover.

In more recent times the focus has shifted from Europa to Mars as the prime candidate for extra-terrestrial life in this solar system. NASA has sent several missions to Mars including small rovers that roamed the Martian landscape sending pictures and dreams of colonization back to Earth.

To everything there is a season and it appears that Europa’s may have swung back into orbit, ascending once again in popularity among those in the interplanetary know. On Monday, September 26 NASA held a news conference, announced a week ahead of time fuelling speculation that life had been confirmed on Europa, unveiling new photos from the Hubble Space Telescope confirming water plumes erupting from the moon’s surface.

The news was not what some were hoping for, and in fact was not new information as plumes had been photographed and published by NASA in 2013, but many continue to believe that Europa is a plausible candidate for life. One such person is Richard Greenberg, Professor Emeritus of Planetary Sciences at the University of Arizona.

Greenberg, who now divides his time between North Carolina and Guysborough, Nova Scotia, was a member of the imaging team for the Galileo mission to Jupiter which launched in 1989 arriving at the planet’s orbit in 1995.

Over a period of eight years Galileo sent streams of data to earth which Greenberg and colleagues used to explore and interpret the processes that shaped Europa as well as studying Jupiter and other solar system bodies.

Greenberg, whose specialty is celestial mechanics, proposed to NASA in the 1970s that the gravitational pull exerted by Jupiter “might actually have an effect on what we would see on the satellites; the geology of the satellites. It turned out to be true although I was speculating at the time.”

The force of gravitational pull exerted on Europa creates tides on the water ice encrusted moon, just as the moon creates tides on Earth’s watery surface. Galileo’s data showed the effects on Europa of being permanently attached to this tidal bungee cord. The heat caused by the continuous to and fro of the tides causes cracks in the ice resulting in what looks uncannily like frost heaves and creates enough heat to liquify the water below the icy surface layer.

How much water lies beneath that ice, an astounding ocean of liquid water 150 kilometres thick. “This moon alone has twice as much liquid water as all the oceans on Earth put together…Having an ocean it has pretty much all the ingredients for life. That’s one of the reasons it is such an exciting place.”

The latest pictures from NASA are fuelling that excitement. The images confirm that in some instances cracks in the icy surface are open long enough and extend deep enough to allow water vapour to escape. Greenberg said of this development, “The real importance is that it shows that the liquid is directly linked to the surface through openings in the ice.”

But none of this is new information, the real story behind the hype of these most recent Hubble Space Telescope pictures of Europa may be political. Congressman John Culberson (R-Texas) has a soft spot for Europa and has been directing money towards a new mission to the watery moon through House appropriation bills for several years. His interest seems to outweigh NASA’s. Under his leadership, the U.S. government agreed to provide five times the amount of funding NASA requested for the 2017 fiscal year to go toward a mission to Europa.

Culberson’s House of Congress webpage provides a detailed look at the congressman’s commitment to a new mission to Europa where he states, “I am so enthusiastic about this mission because I truly believe that when we first find life on another world, it will be in the immense ocean of Europa.”

With such staunch supporters, a new mission to Europa appears to be on the horizon. And while Greenberg counts himself among supporters for such a mission, he doesn’t discount the importance of more in depth exploration of a closer water-bearing planetary body, Mars. “The more we learn about Mars the more plausible it is that there might be life there too. There’s liquid water just under the surface. I wouldn’t be surprised if there was life there,” he said.

Speaking to the exploration possibilities for Europa, Greenberg admits it is a more challenging objective. “Europa is extremely difficult. It is far away. The surface is bombarded by energetic charge particles that would fry any solid state electronics…but I do like the idea of an Europa orbiter with a lander that would land in one of these places where it looks likely that there would be a connection with the ocean…Then you would have a chance of finding life.” 

Europa is making its way back into the collective consciousness. A new mission searching for life on a not-to-distant moon will fuel interest in space exploration just as Colonel Chris Hadfield stint as commander of the International Space Station renewed interest in what was happening thousands of kilometres above our heads in Earth’s orbit. 

“To the moon,” may soon be the cry heard from the launch pad.

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