Water worlds: Looking for life in a liquidy lunar landscape

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Water worlds: Looking for life in a liquidy lunar landscape By Washington Post, adapted by Newsela staff on 09.01.

1 Water worlds: Looking for life in a liquidy lunar landscape By Washington Post, adapted by Newsela staff on Word Count 622 TOP: The puzzling, fascinating surface of Jupiter s icy moon Europa looms large in this newly reprocessed color view, made from images taken by NASA's Galileo spacecraft in the late 1990s. BELOW: An artist's conception of Europa; a composite image of Enceladus; a composite image of Titan; an image of Earth from space. Photo: NASA/JPL-Caltech/ SETI Institute; NASA/ESA/K. Retherford/SWRI; NASA; NASA; NASA The solar system is surprisingly wet. In space, water is everywhere. It's frozen in flying chunks of space rock and floating in the atmospheres of gas giants, huge planets composed mostly of gas. Perhaps most remarkable of all, water is also sloshing about in huge oceans hidden under the icy crusts of far-away moons. These moons are known as "ocean worlds." If there is life in our solar system beyond Earth, there's a decent chance it lives in one of these places. At the Woods Hole Oceanographic Institute, dozens of oceanographers and planetary scientists came together Thursday to discuss how we might explore such worlds. It would be a long trip to the frigid outer edges of our solar system, but there are plenty of beaches to stop at along the way. (You may not want to go swimming in them, though.) Here are a few of the most intriguing ocean worlds. Europa

2 This moon of Jupiter has the smoothest surface of any object in the solar system. It has a thick, icy crust streaked with reddish marks, which scientists think could be deposits of salt from an interior sea. The liquid ocean beneath Europa's crust is kept from freezing by "tidal heating." This means that the act of orbiting Jupiter keeps the moon's interior warm. Europa might share some key characteristics with the oceans on Earth. A study from NASA's Jet Propulsion Lab earlier this year suggested that the moon could have the right balance of chemicals to allow for living organisms. A NASA mission to do several long flybys of Europa is already in the works. Enceladus In 2005, NASA's Cassini spacecraft noticed something strange going on near the surface of Enceladus, one of Saturn's moons. Geyser-like jets of water vapor, carbon dioxide and other gases and particles were erupting from cracks near the moon's south pole. Beneath Enceladus' craggy surface, a liquid ocean is being stirred up by volcanic activity in the moon's rocky interior. It is thought that life on Earth first evolved around similar sea vents on our planet. This characteristic makes Enceladus fascinating to astrobiologists. Carolyn Porco, the imaging team leader for the Cassini mission, said Thursday, that the moon shows promise. She said some astrobiologists regard Enceladus as the best place in the solar system to look for extraterrestrial life. Ganymede Ganymede, Jupiter's biggest moon, is the largest moon in our solar system and the only one with its own magnetic field. Researchers have said Ganymede has a large, salty ocean sandwiched between an inner and outer layer of rock. It could even have several oceans layered between sheets of ice, like a very strange club sandwich. Titan Saturn's largest moon is the only place in the solar system known to have liquid lakes on its surface (other than Earth, of course). The far-flung moon is super cold, with an average surface temperature of minus-292 degrees Fahrenheit. Lakes filled with water would freeze at this temperature, but Titan's lakes are filled with liquid methane and ethane. Scientists think there is a liquid ocean below the surface of Titan. This ocean layer is believed to cause the moon to morph and deform as it responds to Saturn's gravitational pull. Titan has been called the most Earth-like world ever discovered, and it could, in theory, support life. Earth

3 There are parts of Earth's oceans that are as foreign to scientists as any extraterrestrial sea. Scientists didn't discover lifeforms around deep-sea vents until Before then, they imagined the dark, deep ocean as a lifeless place. "Of all the earthbound sciences," said Chris German, a geologist at Woods Hole, "the ocean sciences might be about as close to possible as the science of space."

4 Quiz 1 What idea is suggested by the selections below? The liquid ocean beneath Europa's crust is kept from freezing by "tidal heating." This means that the act of orbiting Jupiter keeps the moon's interior warm. Beneath Enceladus' craggy surface, a liquid ocean is being stirred up by volcanic activity in the moon's rocky interior. Movement may be what keeps the oceans beneath the surfaces of moons from freezing. Liquids like methane and ethane will not freeze on the cold surfaces of moons. One of Jupiter's moons has the smoothest surface of any object in the solar system. Life is more likely to be found on moons that have magnetic fields and water. 2 Which of the following is the STRONGEST piece of evidence that scientists may find life on one of the solar system's moons? Europa might share some key characteristics with the oceans on Earth. A study from NASA's Jet Propulsion Lab earlier this year suggested that the moon could have the right balance of chemicals to allow for living organisms. Researchers have said Ganymede has a large, salty ocean sandwiched between an inner and outer layer of rock. It could even have several oceans layered between sheets of ice, like a very strange club sandwich. Scientists think there is a liquid ocean below the surface of Titan. This ocean layer is believed to cause the moon to morph and deform as it responds to Saturn's gravitational pull. There are parts of Earth's oceans that are as foreign to scientists as any extraterrestrial sea. Scientists didn't discover lifeforms around deep-sea vents until Before then, they imagined the dark, deep ocean as a lifeless place. 3 The central idea of the article is developed by: explaining why oceanographers and planetary scientists work together illustrating the places on moons where scientists have already found life comparing the characteristics of different oceans on Earth describing the conditions on moons that may support life

5 4 Which of these selections would be MOST important to include in an objective summary of the article? Perhaps most remarkable of all, water is also sloshing about in huge oceans hidden under the icy crusts of far-away moons. These moons are known as "ocean worlds." If there is life in our solar system beyond Earth, there's a decent chance it lives in one of these places. This moon of Jupiter has the smoothest surface of any object in the solar system. Researchers have said Ganymede has a large, salty ocean sandwiched between an inner and outer layer of rock.

2007 Pearson Education Inc., publishing as Pearson Addison-Wesley. The Jovian Planets

2007 Pearson Education Inc., publishing as Pearson Addison-Wesley. The Jovian Planets The Jovian Planets The Jovian planets are gas giants - much larger than Earth Sizes of Jovian Planets Planets get larger as they get more massive up to a point... Planets more massive than Jupiter are