“Ganymede: Jupiter’s Largest Moon and Target of ESA’s JUICE Mission”

REPUBLIKA.CO.ID, JAKARTA—Ganymede is a moon of the Planet Jupiter. It is larger than Mercury and Pluto and only slightly smaller than Mars. At the moment Ganymede is the main target for the European Space Agency’s (ESA) Jupiter ice exploration mission (JUICE) which launched on April 14, 2023 at 08:14 EDT (12:14 GMT) which is expected to arrive in the lunar neighborhood Jupiter in December 2031.

Reported from Space, Ganymede is about 4.5 billion years old, roughly the same age as Jupiter. Ganymede is the seventh moon and third Galilean satellite to emerge from Jupiter, orbiting about 1,070 million kilometers. Ganymede takes about seven Earth days to orbit Jupiter.

Ganymede’s average radius is 2,631.2 km. Although Ganymede is larger than Mercury, it has only half the mass, classifying it as low density.

In addition, the average daytime temperature on the surface ranges from -112.7C to -182.7C, according to NASA. Then, Ganymede is the only satellite in the solar system that has a magnetosphere. Commonly found on planets, including Earth and Jupiter, the magnetosphere is a comet-shaped region where charged particles are trapped or deflected.

According to NASA, Ganymede’s magnetosphere is completely embedded within Jupiter’s. Ganymede was discovered by Galileo Galilei on January 7, 1610. The discovery, along with Jupiter’s three moons, is the first time a moon has been found orbiting a planet other than Earth.

Galilei’s discoveries eventually led to the understanding that planets orbit the sun, not our solar system revolving around Earth. He called this month Jupiter III.

When the numerical naming system was abandoned in the mid-1800s, the month was named after Ganymede, a Trojan prince in Greek mythology. Zeus, the counterpart of Jupiter in Roman mythology, brought Ganymede, who took the form of an eagle, to Olympus, where she became cupbearer to the Olympian god and one of Zeus’s lovers.

Ganymede has a metallic iron core, which is overlain by layers of rock topped by a crust of mostly very thick ice. There are also a number of bumps on the surface of Ganymede, which may be rock formations.

In February 2014, NASA and the United States Geological Survey released the first detailed maps of Ganymede in the form of images and video animations created using observations from NASA’s Voyager 1 and Voyager 2 spacecraft, as well as the special Jupiter spacecraft orbiting Galilei.

Ganymede’s surface is mainly composed of two types of terrain: about 40 percent dark with lots of craters, and 60 percent lighter in color with grooves that form intricate patterns to give the satellite its distinctive appearance. The channel, which was most likely formed by tectonic activity or the release of water from beneath the surface, is 610 meters high and stretches for thousands of miles.

It is believed that Ganymede has a sea of ​​salt water beneath its surface. In 2015, a study by the Hubble Space Telescope observed Ganymede’s auroras and how they change between the magnetic fields of Ganymede and Jupiter. The “wobble” seen by the aurora provided evidence that the ocean beneath was likely salty, saltier than Earth’s oceans, scientists said at the time.

However, some scientists are skeptical that Ganymede can harbor life. Due to its internal structure, it is believed that the pressure at the bottom of the ocean is so high that the water below will turn into ice. This would make it harder for any hot-water vents to carry nutrients to the ocean, which is one of the scenarios in which scientists believe extraterrestrial life would occur.