Europa

A technical description of the moon Europa, written as a class assignment for a technical writing course. It's an accumulation on all the most important/interesting information about Europa.

Europa is the sixth of eighty moons that orbit the planet Jupiter. It is remarkable for its potential to house extra-terrestrial life. Europa is sometimes called a Galilean moon, meaning it is one of the four moons observed by Galileo Galilei in 1610. Galileo named the Galilean moons Jupiter I through IV. Europa was Jupiter II and is still sometimes referred to as such. Scientists referred to the moons of Jupiter as numbers until the mid-18th century, when scientists became worried this numeric naming system would lead to confusion as they discovered more moons orbiting Jupiter. The mythological system of naming has been more common since. Europa, like many of the moons orbiting Jupiter, is named after a character from Greek mythology who is a lover to the Greek god Zeus (Jupiter in Roman mythology).
Much of what scientists believe about the moon comes from pictures and measurements taken by space probes launched by NASA (National Aeronautics and Space Administration). In 1973 and 1974, probes Pioneer 10 and Pioneer 11 took close up measurements of Europa and the other Galilean moons. Europa is the sixth biggest moon in our solar system, slightly smaller than Earth’s moon. It completes one rotation on its axis in 85 hours (3½ days on Earth). It also takes this much time for Europa to complete one orbit around Jupiter.
Many of the close-up images we have of the moon were taken by the space probes Voyager 1 and 2 (pictures taken in 1979), Galileo (1995-2003), and New Horizon (2007). By looking at these pictures, scientists are able to know about and guess certain characteristics of Europa. For starters, Europa is covered with ice, making it the smoothest object in our solar system. Meteorites have bombarded the moon for billions of years, yet the surface has few craters or mountains, suggesting the surface of Europa is either relatively new or constantly changing. This most likely means that there is an ocean of salt water under the ice that is constantly reforming the surface. Reinforcing this theory are the dark lines that cover the moon’s surface. Scientists believe these lines, called lineae, are areas of warm ice formed as Jupiter’s gravity pulls on the interior structure of Europa, which behave much like the tides on Earth. If scientists can prove there really is an ocean under Europa’s surface, it would make Europa the most likely place to find extra-terrestrial life.
In May of 2015, NASA announced the Europa Clipper mission. It will study the surface of Europa and find out if there is an ocean beneath the ice. The mission is set to launch in October of 2024.