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Europa : Fact, Myth, Perspective
Ice or Ocean, Crete and Tyre, Dry to None

by Duane Dunkerson

Fact : Maybe

In 1610 both Galileo and Marius sighted the four principal moons of Jupiter. Europa is one of the four and is the smallest of the four. It is second in position outward from Jupiter.

Europa had been a point of highly reflective light in orbit about Jupiter until the spacecraft, Voyager, showed mostly grooves and ridges on its water-ice surface. Decades later the Galileo spacecraft has confirmed what Voyager saw for us. Galileo has brought more to our attention. We have become mostly interested in the amount of water that may be present and in the possibility of life below the surface in conjectured vast seas of water.

Brother Guy Consolmagno hit upon both possibilities of abundant water and life on Europa. His 1975 thesis proposed that Europa was a moon with an icy covering and an ocean below that frozen crust. In an appendix for this thesis he touched lightly on the possibility of oceanic life below the surface.

He pointed out that John Lewis in 1971 had noted that the moons of Jupiter and Saturn were most likely of rock and water ice. Their surfaces were bright. By the middle 1970's, infrared spectra of Europa had been obtained. The spectra matched those of water ice. Father Guy thought Europa's water was nearly all melted with a thin icy crust. He proposed about 100 km of water.

He talked briefly with Carl Sagan at a scientific conference about his thesis. Sagan coolly inquired how life-giving energy could be provided without sunlight penetrating the icy crust? Father Guy briefly thought how about life by means of energy from a volcano? No one had seriously heard of such a thing.

In the late 1970s oceanographers here on Earth found volcanic vents under the Atlantic that had colonies of life - living by means of energy supplied by the chemical reaction between lava and the seawater into which the lava flowed. In 1983, a group of scientists also thought life was in Europa, that heat was supplied by tidal action, and that lava flows gave life.

They were giving life in an underground ocean, second to none in size for the Solar System. Vast quantities of water could be available. We don't want distilled water. We want salty stuff, a brine made up of dead cells from a part of a living mass.

No taste tests have been done from the water in Lake Vostok but many common and strange organisms have been found in ice cores taken from above it. Lake Vostok, the size of Lake Ontario, lies 4 km under the ice of Antarctica. Apparently geothermal heat put the water into liquid form. A Vostok-like ocean could be on Europa.

Perhaps there is also a volcanic heat source on Europa. If not, or in addition to it, there may be tidal friction brought on by Jupiter's gravitational proximity causing a tidal bulge that alters shape and position to push-pull tidal forces.

A magnetometer on Galileo showed that a magnetic field for Europa varies periodically. This can be explained by an electrically conducting liquid like saltwater. Ice is not a good conductor. Europa's magnetic field is a secondary one induced by and responding to Jupiter's magnetic field.

Galileo also got good looks at Thera and Thrace. They are dark terrain that may be local meltdown of the ice. They could be projecting from the interior or they could be on their own, up in the ice floes of Europa's surface.

Thin ice or thick ice? Lots of water? These and other questions may have answers provided for by Europa Orbiter. This proposed mission would have on board a radar capacity to measure the thickness of the ice, establish if there is water below the crust that is liquid, and assess tidal forces on Europa- if Europa has an ocean. There is talk of later missions to dispatch remote-controlled undersea craft to seek life.


Myth: Beautiful
Europa was the daughter of Agenor. He was a Phoenician. The Phoenicians were ancient seafarers with a range all about the Mediterranean. Europa is now immortalized on a moon that may allow for seagoing voyages far beyond the maritime dreams of those ancient Phoenicians. They traded with Cyprus, Egypt, India, Spain, and Africa. A famous dye, from the murex snail, was a hot item. The Phoenicians also had an alphabet of 22 consonants. It was contributory to the Hebrew and Arabic writing. Carthage was theirs until 146 BC.

Cretans say, not they, but Zeus, as a white bull, took Europa from her city of Tyre. She was taken by whatever agent to Crete. Zeus gave her gifts. One of these gifts was a javelin that, if thrown, never missed. We do not have a name for the javelin. Zeus also gave her Laelaps, a dog, which never missed its meat. Europa Orbiter could be favorably named as Europa's Javelin or as Laelaps.


Perspective : Raspy Water

Not so long ago life was preposterous - beyond earth. There was a greatness and a delicacy here that most were sure could not be duplicated. Perhaps Mars, as the abode of life as Lowell put it, in the time of the Mars mania, cooled off a great many from any expectant stance for life elsewhere in the Solar System.

Our telescopes and attendant apparatus could not find life beyond us. Then spacecraft soared skyward and out to Mars and Europa. A great deal of water may be at one or both places.

We aren't ready for life-not-as-we-know-it. We eagerly seek water there. Once all was dead but us. The needle had gone over hard right, very conservative views of life's elsewhere possibilities were stated. Now the needle has pegged, it is slammed far left, there are very liberal possibilities feeding on scraps of information.

We may be anticipating more than the life there - we may be dreading a badly burnt earthbound psyche. We see ourselves parched, teetering on dry stack of rocks, with a river in the distance. One river would not be enough for the planet. The brilliant lies of the anti-environmentalists can't provide enough room for us on the banks of a single river. And so in the future….

The latest transport from Europa releases gigantic splashes in the sky. Like baby robins in a nest we crane our necks awkwardly with mouths agape, flopped out, for a drop or two. We don't want anymore of what is not the best of life, a grating, sandy water to drink.

We are all incomplete and deficient in the present. Gone away into the past are the slender, not gaunt, ones. We have elixirs, little better than what exudes from sebaceous glands. We lick the water from the scales of a fish.

No more water hazards, or water clock, sand in the hourglass is most appropriate. Water wagons are dismantled. The back-up beeper on the water truck has no sound to make. Magical implications of a long, relaxing shower are only read about.

We may need a bucket brigade from Europa. Never mind the occasional exotic rotifer in the water. Drink it down. Don't gulp, enjoy it for such a little while at least.

There are no natural manifestations of aquatic purity, no rapids, all are pools, simmering in the heat. No breakers, no carafes one could scoop into the freshwater surf.

What comes from the sky is a dry mist, insubstantial, we camels of an enlarging desert see fullblown mirages of a persistent oasis where the grass is not a painted green collection of tiny sharp rocks. Super soaker, wetlands, spillways, the smell of rain -all gone.

You don't splash any water on your face, what a waste. It goes into the mouth. Better dirty than dead. Some dislike the slogan and get to be too thirsty. Is that what some said? I can't hear you…can't hear you…water's running. In a dream.


 

 

   

 

 
 
 
 
 

 

 

 

 



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