Europa does the wave to generate heat

December 12, 2008

One of the moons in our solar system that scientists think has the potential to harbor life may have a far more dynamic ocean than previously thought.

If the moon Europa is tilted on its axis even slightly as it orbits the giant planet Jupiter, then Jupiter's gravitational pull could be creating powerful waves in Europa's ocean, according to Robert Tyler, an oceanographer with the University of Washington's Applied Physics Laboratory and author of a letter in the Dec. 11 Nature. As those waves dissipate, they would give off significant heat energy.

Depending on the amount of tilt, the heat generated by the ocean flow could be 100 to thousands of times greater than the heat generated by the flexing of Europa's rocky core in response to gravitational pull from Jupiter and the other moons circling that planet.

That's the current assumption - that oceans on moons are heated mainly by this flexing of their cores. In the case of Europa, it also has been thought that the thick ice covering its ocean probably generates some heat as two sides of cracked ice rub together in response to gravitational pull.

"If my work is correct then the heat source for Europa's ocean is the ocean itself rather than what's above or below it," Tyler says. "And we must form a new vision of the ocean habitat that involves strong ocean flow rather than the previously assumed sluggish flows."

Both are important considerations if exploratory missions are ever sent to Europa in search of life. Europa, which is slightly smaller than Earth's moon, is one of Jupiter's 63 moons. With surface temperatures as cold as minus 260 degrees Fahrenheit, Europa's surface is covered with a thick layer of ice. There is evidence of a liquid ocean beneath the ice and, if there is volcanic activity on the sea floor, this could be a recipe for generating microorganisms that live without sunlight, perhaps like the microorganisms found at hydrothermal vents and other places on Earth.

Many planets and moons are known to be tilted within their orbital plane. The Earth, for example, has an axial tilt of about 23 degrees. It's why the northern and southern hemispheres have different seasons, depending on whether they are tilted more toward or away from the sun.

Previous theoretical calculations expected Europa to have an axial tilt of at least 0.1 degrees. It hasn't been measured and could be bigger than this. But even at this minimum value the tidal flow on Europa using Tyler's new calculation is quite strong - some 10 centimeters a second - and enough to cause significant heating.

The new calculation differs from previous ones in that it allows a more realistic dynamic response of the ocean to the tidal forces.

His assumptions and calculations led him to say that he thinks this kind of wave action could be the dominant heat source in the oceans of Europa and other moons.

"But this proposal is a relatively new contender - so let's see how it does," he says. Tyler is the sole author of the letter in Nature. His work was supported by NASA's Outer Planets Research program.

University of Washington

---

---

	Europa (Spanish Edition) by EL PAÍS Selección Europa' es el proyecto de EL PAÍS y otros cinco periódicos líderes en los seis países más grandes de la Unión Europea para compartir el debate, los análisis, los reportajes y las firmas en torno a un objetivo común: el repaso de una realidad convulsa y los desafíos que han sometido a la Unión a las mayores tensiones conocidas en sus 60 años de existencia. EL PAÍS, Le Monde, The Guardian, La Stampa, Gazeta Wyborcza y Süddeutsche Zeitung, periódicos de la máxima influencia en España, Francia, Reino Unido, Italia, Polonia y Alemania, han unido esfuerzos en este suplemento. Los seis suman 1,9 millones de ejemplares diarios y más de 10 millones de lectores de audiencia. La canciller de Alemania, Angela Merkel, analiza aquí, en una entrevista conjunta, las metas que se ha...
	Unmasking Europa: The Search for Life on Jupiter's Ocean Moon by Richard Greenberg (Author) Jupiter's ice moon Europa is widely regarded as the most likely place to find extraterrestrial life. This book tells the engaging story of Europa, the oceanic moon. It features a large number of stunning images of the ocean moon’s surface, clearly displaying the spectacular crack patterns, extensive rifts and ridges, and refrozen pools of exposed water filled with rafts of displaced ice. Coverage also features firsthand accounts of Galileo’s mission to Jupiter and its moons. The book tells the rough and tumble inside story of a very human enterprise in science that lead to the discovery of a fantastic new world that might well harbor life.
	Europa, Europa by Solomon Perel (Author), Margot Bettauer Dembo (Author) The Inspiration Behind The Golden Globe --Winning Film "An engrossing and memorable tale."Jewish Book World "The sheer emotion of telling the tale is palpable. The whole is moving, and strange beyond belief." --The Times (London) International acclaim for Solomon Perel's Europa Europa "The wrenching memoir of a young man who survived the Holocaust by concealing his Jewish identity and finding unexpected refuge as a member of the Hitler Youth. "It is a Holocaust memoir that is moving, straightforward, and quite completely bizarre, unsettling in all kinds of assumptions about identity, responsibility, and guilt." --Glasgow Herald "Perel bares his soul to readers in this fascinating, unusual personal narrative of the Holocaust." --Book...
	Europa by Nicholas Faraday (Author), Heidi Fuqua (Contributor) By the year 2123 climate change has decimated the Earth's most precious resource, her oceans. Worldwide droughts have created massive deserts where lush countryside once existed. The seas have turned toxic and the polar caps have disappeared. With its habitat quickly shrinking, humanity needs a silver bullet. Ten teams have been dispatched to Jupiter's sixth moon, Europa, and are tasked with retrieving a micro-organism known as Archaelleonous from the frozen moon's sub-ice liquid ocean. This precious resource is believed to be the key to restoring life to the Earth's oceans and resetting the climate. Told from the perspective of each crew member, this is the story of the last days of Galileo Team 10. Six and a half years into a mission besieged with tragedy, complications and...
	Europa (Space Science Series) by Robert T. Pappalardo (Editor), William B. McKinnon (Editor), Krishan Khurana (Editor) Few worlds are as tantalizing and enigmatic as Europa, whose complex icy surface intimates the presence of an ocean below. Europa beckons for our understanding and future exploration, enticing us with the possibilities of a water-rich environment and the potential for life beyond Earth. This new volume in the Space Science Series, with more than 80 contributing authors, reveals the discovery and current understanding of Europa’s icy shell, subsurface ocean, presumably active interior, and myriad inherent interactions within the Jupiter environment. Europa is the foundation upon which the coming decades of scientific advancement and exploration of this world will be built, making it indispensable for researchers, students, and all who hold a passion for exploration.
	Europa Strike: Book Three of the Heritage Trilogy by Ian Douglas (Author) 2040: Ruins of ancient civilization uncovered on Mars reveal startling truths about the creation of humankind.2042: In the gray dust of the Earth's Moon, an extinct enslaving race left behind more answers, more questions...and a grim warning.2067: As Earth's warring factions clash in space for scraps of alien technology, a strange artifact lies trapped beneath the ice-locked oceans of Europa: a machine that holds the key to the final human destiny.It is called "The Singer" for the eerie tone it emits.An artificial intelligence built eons ago, it may ultimately solve the mystery of the vanished alien races responsible for the birth and development of humanity. But after decades of war, the hostile nations of Earth care more for power than for knowledge. And now all that stands between the...
	Europa by Tate Publishing Jonas Black lives a peaceful life in the Europa mining colony and has spent the last two years building Manta--a submarine with an onboard artificial intelligence that soon becomes one of his closest friends. When Jonas embarks on a journey to explore the planetary ocean of Jupiter's moon Europa, he does not expect to discover the secret beginnings of life on the planet and place himself on the edge of a battle for his very life. Deep in the trenches of Europa's ocean Jonas discovers an abandoned undersea science facility, and although the magnificent ship he salvages from it is even better than the sunken treasures of old, the mystery lurking within this facility is chilling. Once surfaced, Jonas must quickly discover what he is made of and reconcile the collapse of his near religious...
	Europa by Tim Parks (Author) A finalist for the Booker Prize, this ferociously comic tale of love gone sour is the finest novel to date from the author of the national bestsellers, "An Italian Education" and "Italian Neighbors".
	Omar the Immortal: Europa (Volume 1) by Joseph Robert Lewis (Author) In the exotic land of Marrakesh, Omar Bakhoum joins an airship expedition into the freezing north in search of a fabled country called Ysland, but howling ice storms, legions of ghosts, and a deadly samurai stand between Omar and his goal. His journey has barely begun before the members of the expedition team begin dying, and as the last remaining foreigner on board, Omar is accused of the murders. The one thing that can help him find the real killer is Omar's ancient sword, haunted by the souls of thousands of dead sages and warriors. But this sword may be the very thing that dooms the entire expedition to a watery grave.
	The Rape of Europa: The Fate of Europe's Treasures in the Third Reich and the Second World War by Lynn H. Nicholas (Author) Winner of the National Book Critics Circle Award The cast of characters includes Hitler and Goering, Gertrude Stein and Marc Chagall--not to mention works by artists from Leonardo da Vinci to Pablo Picasso. And the story told in this superbly researched and suspenseful book is that of the Third Reich's war on European culture and the Allies' desperate effort to preserve it. From the Nazi purges of "Degenerate Art" and Goering's shopping sprees in occupied Paris to the perilous journey of the Mona Lisa from Paris and the painstaking reclamation of the priceless treasures of liberated Italy, The Rape of Europa is a sweeping narrative of greed, philistinism, and heroism that combines superlative scholarship with a compelling drama.