The constant tugging heats up Io’s interior, melting rock into lava. Io orbits between Jupiter and two of the planet’s other moons, Europa and Ganymede, and this configuration means that Io is subject to the gravitational forces of all three. The team targeting Io knows about a phenomenon the Voyager scientists didn’t, called tidal heating. Soon, perhaps, they will get a closer look at what exactly makes these extraterrestrial blasts tick. In the 40 years since, planetary scientists have moved from monitoring eruptions on Earth to finding them sprinkled across the solar system. “It was very hard for people to accept that such a small moon like Io could still have active volcanism, because Io should have cooled a long time ago,” Lopes said. Instead, Voyager found the first, surprising evidence of volcanic activity somewhere besides our planet. The moons around Jupiter, for example, are about the size of our moon or smaller, so it stood to reason that they, too, would be cold, still, and speckled with craters. In the 1970s, as the Voyager mission cruised toward the outer planets, scientists predicted that the spacecraft would find moons like our own. “Volcanism is like a window into the interior of the planet,” says Sue Smrekar, an astronomer at NASA’s Jet Propulsion Laboratory who is leading one of the proposed missions. Small bodies, like our moon, should go cold faster than others, and spurts on the surface can reveal the invisible contours of a world deep within. As a rule, volcanic activity indicates that a world is cooling off after planets and moons form-an extreme and fiery process-they can spend billions of years ejecting heat from their interiors through cracks in the surface. Not long ago, Earth held the title for the most volcanic spot in the solar system. Recently, NASA announced it would fund proposals for four new robotic missions, all headed for a close look at these kinds of worlds-Io, Venus, and Triton, a moon of Neptune. Other volcanic spots are scattered across our neighboring planets and moons, too, and probably countless more in other solar systems across the universe. Today, Io is known as the most volcanically active place in the solar system. They were several hundred million miles away, on a moon of Jupiter called Io. None of the volcanoes were on Earth, though. Lopes ended up in the 2006 edition, recognized for discovering the most active volcanoes anywhere. “‘You’re going to be in the Guinness World Book of Records’”-until one day, one of those offhand comments made its way to somebody who actually worked for Guinness World Records. “People used to joke with me, ‘Oh, you found another active volcano!’” Lopes told me. Using data from an orbiting probe, she picked out eruptions across the fiery surface, eventually spotting 71 active volcanoes that no one had ever detected before. Rosaly Lopes spent five years carefully inspecting a churning landscape where molten rock spilled forth like the arced jets of a water fountain.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |