Emerald Robinson: Hi I'm Emerald Robinson and in this What Is video we're checking out one of Jupiter's most fascinating moons, Europa, named for a Phoenician princess who was one of Jupiter's many love interests Europa was discovered in 1610, almost simultaneously by Galileo and Simon Marius.
Europa is about 1900 miles in diameter, a little bit smaller than earth's moon. This makes it the sixth largest moon in the solar system. Like our moon Europa has what's called synchronous rotation, meaning that its rotation and revolution times are almost identical, and the same side always faces Jupiter. Unlike our moon however, this takes only about three and a half days instead of about thirty days.
Europa does not have a strong gravitational pull. Objects weighing 100 pounds on earth would only weigh 13 pounds on Europa. Europa's atmosphere is made of oxygen, but it's much too thin for humans to breathe.
Of Jupiter's 66 moons Europa is the sixth one away from the surface orbiting in a nearly perfect circle roughly 414,000 miles from the planet's center. Europa's average temperature ranges from about -260 degrees Fahrenheit below zero at the Equator to about -370 degrees Fahrenheit at the poles.
Europa's frozen surface is very smooth and reflects a lot of light. This is because it's covered with an icy crust that's 18 miles thick. Scientists think the crust covers an ocean similar to Earth's.
This underground ocean is kept from freezing by tides caused by Jupiter's strong gravitational pull. Because the ocean is so like Earth's, many scientists think that Europa could harbor some kind of extraterrestrial life. Perhaps we'll find out when the European Space Agency sends a new probe to explore Jupiter's icy moons scheduled for the year 2022.