Titan's tides: Looking for life in lunar lakes and oceans By Washington Post, adapted by Newsela staff on 08.31.16 Word Count 615 Level 950L 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. NASA/JPL-Caltech/SETI Institute; NASA/ESA/K. Retherford/SWRI; NASA; NASA; NASA There's more water throughout the solar system than you might expect. In space, water is everywhere. It's frozen in flying chunks of space rock. It's floating in the atmospheres of gas giants, huge planets composed mostly of gas. Perhaps most remarkable of all, it's sloshing around in huge oceans beneath the icy crusts of distant moons. These moons are known as "ocean worlds." If there is life in our solar system beyond Earth, there's a good chance it lives on one of these moons. Dozens of scientists met Thursday at the Woods Hole Oceanographic Institute, a research center for marine science, to discuss how we might explore ocean worlds. It would be a long trip, taking us to the freezing outer edges of the solar system. But there are plenty of beaches to stop at along the way. (You may not want to go swimming, though.) Here are This article is available at 5 reading levels at https://newsela.com. a few of the most interesting ocean worlds. Europa This moon of Jupiter has the smoothest surface of any object in the solar system. It has a thick, icy crust with reddish marks that scientists think could be deposits of salt from an interior sea. The ocean beneath Europa's crust is kept from freezing due to "tidal heating." This means the act of orbiting Jupiter keeps the moon's interior warm. Europa might share some important characteristics with the oceans on Earth. Earlier this year, a NASA study suggested that the moon might have the right balance of chemicals to allow life to form there. NASA is currently planning a mission to do several long flybys of Europa. Enceladus Enceladus is one of Saturn's moons. In 2005, NASA's Cassini spacecraft noticed something strange near its surface. Jets of water vapor, carbon dioxide and other gases were exploding from cracks near the moon's south pole. Beneath the moon's surface, volcanic activity stirs up a liquid ocean. Scientists think that life on Earth first evolved around similar vents, or openings, on the sea floor. This connection makes Enceladus exciting to scientists. Carolyn Porco is a team leader for the Cassini mission. She said Thursday that the moon shows promise. Some scientists think it may be the best place in the solar system to look for life, she said. This article is available at 5 reading levels at https://newsela.com. Ganymede Ganymede is Jupiter's largest moon, and the largest moon in our solar system. It is also the only moon with its own magnetic field. Researchers think Ganymede has a large, salty ocean between two layers of rock. It could even have several oceans packed in between layers of ice, kind of like a 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). This far-flung moon is super cold. The average surface temperature is minus-292 degrees Fahrenheit. The lakes are filled with methane and ethane, rather than water, which would freeze. Scientists think that a liquid ocean layer below Titan's surface causes the moon to change and deform in response to Saturn's gravitational pull. Titan has been called the most Earth-like world ever discovered. It could, in theory, support life. Earth There are parts of Earth's oceans that are as unknown to scientists as any extraterrestrial sea. Scientists didn't discover lifeforms around deep-sea vents until 1977. Before then, they thought the dark, deep ocean must be a lifeless place. Now they see more possibilities to discover strange new life in the deep sea as they do in space. "Of all the earthbound sciences," said Chris German, a scientist at Woods Hole, "the ocean sciences might be about as close to possible as the science of space." This article is available at 5 reading levels at https://newsela.com..