Irene Baron: www.irenebaron.com
Ever since I learned about Europa, one of Jupiter’s moons, I have been thinking it may harbor life.
Europa is smaller in diameter than Earth’s Moon by almost 300-miles. Like our Moon, the same side of the orb faces the planet it revolves around. The lava flows on our Moon may be creating an increased gravitational pull toward Earth due to the heavy and dense basaltic type igneous/lava rock. The Earth’s pull on the lava flows effectively keep us from seeing the back side of the Moon from Earth. Europa does not have such lava flows visible. If they exist, they would be under the ice and liquid covering the visible surface. Why else would the same side of the moon always face Jupiter?
Or … perhaps the solid core of Europa is similar to the irregularly shaped solid inner core of Earth. If one side of Europas’ irregularly shaped core is slightly off center, or more dense than the other side, it may cause the same hemisphere of Europa to always face Jupiter, again due to gravitational attraction.
WHY MAY LIFE BE FOUND ON EUROPA?
Take the physical attributes of that orb into consideration in answer to the question. The first thing you see is the slowly changing surface of the water ice covering liquid below. If the material below the water ice were solid, there would not be much movement of the ice which exhibits evidence of flows. When one examines ice flows on Earth, such as those that occur within the Arctic icecap, the views are similar to those on Europa.
As the Arctic icecap moves, features are formed upon its surface which mimic those of Europa. Europa does have some smooth areas as viewed from space probes.
Reading articles in the past about research teams trying to maneuver across such Arctic icefields with their horrendous ridges, crevices, towers of jutting ice, and little or no smooth areas, I would guess robotic or human teams on Europa would have the same level of difficulty. Not only is the topography of the ice rough, the ice is slowly moving.
To see a time lapse video illustrating the results of that Earth ice motion, click on the 1-minute long YouTube link below. This shows how fractures formed in the ice of the Beaufort Sea off the north coast of Alaska during February and March 2013. The images were captured by the Suomi NPP satellite using the Visible Infrared Imaging Radiometer Suite (VIIRS). As you watch the video, imagine you are watching the icy surface of Europa being moved by currents of water beneath it.
WHAT WOULD CAUSE EUROPAN TIDAL CURRENTS?
Perhaps temperature changes within the liquid mass under the ice cause currents. We all learned that hot (less dense) water rises and cold (more dense) water descends. What would be heating the water on the ocean floor to cause these density currents?
If Jupiter’s’ moon IO has volcanic eruptions caused primarily by changing gravitational attractions to Jupiter, Europa could also. That would make the solid region of Europa have a higher temperature than the surface that is exposed to the absolute cold of space. Europas’ orbit is slightly elliptical. The gravitational attraction to Jupiter changes as Europa reaches perigee (closest point to Jupiter in its orbit) and apogee (furthest point to Jupiter in its orbit. It also experiences gravitational pulls from the other moons. At perigee as the gravitational attraction increases between Jupiter and Europa, the moon loses its spherical shape and elongates. By the time it reaches apogee, it again becomes more spherical in shape. The changing gravitational attractions create a tidal force which may change the interior of the moon. That tidal force may generate heat to keep the ocean liquid. Thus you have tidal currents formed.
THE RESULTING HEAT CAUSES OTHER PHENOMENA.
If Europa has a solid crust over magma or a hot core, water could filter down through cracks to become heated, expand, and rise. The rising liquid could create features on Europas’ ocean floor similar to the black smokers on Earth.
A black smoker exists when superheated water that has moved near magma rises into the cooler liquid above the ocean floor. The superheated water will have dissolved many minerals from the rock through which it passes. As the plume of black smoke rises from the rock and is cooled by the liquid above, the solid material/minerals within in precipitate out, falling downward to create a chimney type mound of sediment. With its minimal gravity, the black smoker mounds on Europa could grow to be larger than the one discovered along the Juan De Fuca Ridge west of California at 15-stories high.
A good article about black smokers can be found at: http://www.amnh.org/learn/pd/earth/pdf/black_smokers_incubators.pdf .
If the height of some black smokers extend to and/or melt through the surface of ice, the liquid material they expel freezes. The minerals within the material would drop to the ice and form a pattern of what some astronomers have called “freckles” on the surface of Europa as pictured in the NASA image below. Since the expelled material is warm, you see the effect of ice-melt craters around the “freckles.” The water or liquid would instantly vaporize in the cold of space.
Sometimes the material ejected above the ice is water. Did you ever watch a video of someone on Earth throwing boiling water into subzero air to see it instantly turn solid? That is what happens on Europa where the temperature above the ice is less than the average -300 o Fahrenheit. Any material ejected becomes vapor. With little gravity, it can easily escape into space. Below is a NASA image showing such an eruption on Europa. That image can be found online at: http://www.nasa.gov/content/goddard/water-vapor-over-europa/ and Hubble spots water spurting from Europa'. Notice how smooth the rest of the planet appears from space.
WHY WOULD THERE BE LIFE ON EUROPA?
Scientists have stated that Europa has the ingredients necessary for the origin of life. It has a warm liquid mass in which organisms may flourish. True, live organisms have been found in most all temperatures and conditions, but warm liquid is a prime condition. Life on Earth has been discovered miles under water surrounding the warm black smokers of volcanic vents. The organisms don’t need light for energy and survival. They use chemicals instead.
The “freckles” of expelled material are made up of silicate minerals. Some interested persons call the expelled silicate materials ‘outgassing’. Ninety percent of the Earths’ surface is made up of silicate minerals. It is believed much of the solid mass of Europa is made of silicate materials. Silicates have silicon and oxygen present in addition to other elements. Clays tend to be aluminum silicates. Much of the clay on earth has been formed from weathering and erosion of igneous formed crystals of orthoclase and plagioclase feldspar. Feldspar is usually the gray or pink material in igneous granite. The white material in granite is quartz, a pure silicate (SiO2). Think about how much clay exists on the earth and how it, in the varied compositions, provides materials to support life. If the outer mantle of solid Europa is clay, there may be much life.
HOW WOULD WE KNOW?
The ice would have to be penetrated. Just how deep is the ice of Europa? If robots are not able to drill through the thinnest ice to sample the warmer water for living microscopic organisms, perhaps an elite, human drilling team can be sent one day, such as fictionalized in the science fiction movie, Armageddon. The rig would be expensive to get into space, but once there would appear weightless and easy to move to Europa. Getting it to the surface safely without damaging the ice or sinking the rig could prove to be a problem. Such a venture would also create innumerable problems financially, politically and technologically. Would a drill hole damage any possible life below the ice? Not any more than the shifting surface ice would.
Why would anyone even think about doing such a thing? Because humans are innately curious.
But, if we are patient and wait around long enough, perhaps some superior, technological alien species will arrive and do it for us. After all, Europa contains almost twice as much water as exists on Earth. I would guess that such water, if clean, might be a hot commodity in our galaxy. If it is proven there is no life on Europa and the water is pure, we could have the aliens transport what we need to Earth to replenish our polluted oceans and sell them the remaining water. :-)
Since all nations own the planets, all the nations would own Europa. By selling the water, every nation would become debt free. What ramifications would that cause?
The Europa Clipper is the vehicle being considered for the trip to Europa. A NASA artist’s conception of the space probe is to the left. Image credit: NASA/JPL Caltech
Congress allocated $43-million in 2013 and $80-million in 2014 for a Europa mission. If possible, the water in the geyser type eruptions could be studied rather than drilling through the ice. That may include the Europa Clipper, a space vehicle planned to orbit Jupiter and make flybys of Europa. See also: http://www.jpl.nasa.gov/missions/europa-clipper/ . Right now NASA is asking scientists what type of mission could be accomplished for less than $1-billion.