Europa

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Europa is one of Jupiter’s Galilean moons. Galilean moons refer to the four moons of Jupiter which were discovered by Galileo way back in January 1610. The Galilean moons are the biggest moons that orbit Jupiter, with Europa being the smallest among the four.

Compared to our own planet’s natural satellite, the Moon, Europa is slightly smaller. Europa has a mean radius of 1,569 km while the Moon has 1,737 km. This size of Europa makes it the sixth largest moon in the entire Solar System.

Here are the top 10 largest moons in the Solar System and their respective mean radii, arranged from largest to smallest: Ganymede (2,634 km), Titan (2,575 km), Callisto (2,408 km), Io (1,818 km), Moon (1,737 km), Europa (1,569 km), Triton (1,353 km), Titania (788 km), Rhea (764 km), and Oberon (761 km).

Europa is mainly composed of silicate rock but is believed to have an iron core. Interestingly, images of Europa show that its surface is very smooth; in fact, one of the smoothest in the Solar System. Although there are noticeably fewer craters on its surface than what is normally seen in popular moons like our own, Europa is striated by cracks and streaks.

Above the surface is a weak atmosphere composed primarily of oxygen. This thin atmosphere provides a very week atmospheric pressure, about 10^-12 times that of Earth’s. Its atmosphere also has a charged layer, known as an ionosphere.

Mainly because of the smoothness of Europa’s surface, some scientists suggest that this moon may have a huge body of water underneath. Now, whenever water is mentioned, some people are quick to point out, and rightfully so, the possibility of biological life.

Most of what we know of Europa were results of fly-by missions of the unmanned spacecraft, Galileo. Due to the possibility of finding extraterrestrial life there, Europa is among the celestial bodies that are being seriously considered for future exploratory missions.

One of the future missions being considered may entail the use impactors. These are parts of orbiters that are deployed into a controlled crash on the surface of interest. The moment the impactor strikes the surface, it could release a plume of debris. Data from the plume could then be collected by another spacecraft trailing the impactor.

Want to know more about the largest moon in the Solar System? We have an article about it here in Universe Today. If you’re more interested in Jupiter’s neighbor, Saturn, you might want to know what Saturn’s rings are made of.

Here’s a closer look of another moon in the Solar System from NASA: Dione at NASA. Here’s another one of Dione from the same site.

Relax and listen to some interesting episodes at Astronomy Cast. Want to know more about Ultraviolet Astronomy? How different is it from Optical Astronomy?

Reference:
NASA

Tagged as: Europa, Galilean moon, Jupiter, Moon, Solar System