Yesterday we learned about Jupiter’s most popular moon – Europa. Today let us learn a few Ganymede facts, which is the largest moon of the gas giant. It is one of the most interesting natural satellites of this solar system because scientists believe it has liquid salt water ocean that can harbor life. So instead of wasting time any further, let us learn some Ganymede facts, shall we?
Interesting Ganymede Facts: 1-10
1. Out of 67 moons of Jupiter, Ganymede is the largest moon and belongs to the group of 4 largest moons of the gas giant that are together known as the Galilean Moons.
2. It is not only the largest natural satellite of Jupiter but it is also the largest natural satellite of our entire solar system.
4. Ganymede is also slightly smaller than Mars. This is the reason why if Ganymede did not orbit Jupiter and instead orbited the Sun, we would have easily classified it as a full-sized planet.
5. Ganymede boasts a diameter of 5,268 kilometers and has a total mass of 1.4819 x 1023 kilograms.
6. The moon orbits the gas giant planet at a distance of 1,070,400 kilometers and takes a total time of 7 earth-days and 3 earth-hours to complete one complete orbit around its host planet.
7. This moon of Jupiter was first discovered by Galileo Galilei on 7th of January 1610. It was the same day when Galileo discovered the rest of three Galilean moons – Europa, Callisto and Io.
8. Compared to Mercury, Ganymede is 8% larger in size and compared to Earth’s moon, this natural satellite of Jupiter has twice as much mass.
9. This moon was originally named as Jupiter III by Galileo but the numeric naming system was given up in the 19th century. The name Ganymede was adopted after Johannes Kepler – a German astronomer and mathematician came up with a suggestion.
10. The name of Ganymede comes from Greek Mythology. In Greek Mythology, we have a called Zeus (who is actually a counterpart of Roman god Jupiter). It is said in Greek Mythology that Ganymede – a prince was carried to Olympus by Zeus where Ganymede became cupbearer for Olympian gods and also became a lover of Zeus.
Interesting Ganymede Facts: 11-20
11. Ganymede travels around Jupiter at a speed of 24,321 miles an hour or 39,165 kilometers an hour. However, it is tidally or gravitationally locked with Jupiter. This means that only one side of Ganymede always faces Jupiter.
12. By the time Ganymede completes one orbit around Jupiter, Europa manages to orbit the planet two times while Io orbits the planet 4 times.
13. Here is one of the most interesting Ganymede facts is that Ganymede is the only moon in the entire solar system which boasts its very own magnetic field. However, this magnetic field cannot be easily recognized because it is totally embedded within the massive magnetosphere of Jupiter.
14. In case you need further clarification, a magnetosphere is actually a region close to a celestial body in which charged particles are deflected or trapped within a region that resembles the shape of a comet.
15. Scientists believe that the magnetosphere of the Ganymede is a result of convection currents inside the molten iron core of this natural satellite.
16. As far as the structure of Ganymede is concerned, scientists are sure that the core of the moon is made of molten metallic iron surrounding a solid iron core. Surrounding the core is a layer of rocks which is the mantle and above the mantle is the crust which is most ice – very thick ice.
17. Photos captured by NASA’s Voyager 1 and 2 and Galileo spacecrafts reveal two distinct types of terrains on this largest moon of Jupiter. One type of terrain is dark and is riddled with craters. This terrain type covers 40% of the total surface area of the moon.
18. On the other hand, the remaining 60% of the terrain has a lighter color and there are grooves that create very delicate patterns, which is why the moon looks the way it does.
19. Scientists think that these grooves that are estimated to have a height of nearly 2,000 feet were formed either because water was released from underneath the crust or because of tectonic activities of the celestial body.
20. Photographs by NASA has revealed that these grooves actually run for thousands of miles, making those intricate patterns.
Interesting Ganymede Facts: 21-30
21. Talking of water, scientists think that even Ganymede, just like Europa has a salt water ocean. However this ocean, according to scientists, is not close to the crust as in case of Europa. Experts believe that the ocean lies at a depth of 124 miles beneath Ganymede’s crust.
22. Interestingly, scientists say that it may be possible that Ganymede actually has two layers of underground ocean of salt water. That’s kind of out of the world thinking but literally, Ganymede is out of the world. A possible explanation for this possible hypothesis is that Jupiter’s gravitational tug on the moon leads to underground friction which causes the layers oceans.
23. It is highly possible that Ganymede can harbor life. Why so? We know from our Earth that wherever there is liquid water, organic life exists. So, if Ganymede has water ocean, it may actually harbor life. This will however take years of studies only to confirm the presence of liquid water. Life detection may not take place in our lifetime.
24. The temperature of Ganymede is a literal killer. On the surface, the average daytime temperature of the moon ranges between -113 and -183 degrees Celsius or -171 and -297 degrees Fahrenheit.
25. At night, the average surface temperature of Ganymede dips even further and hovers at around -193 degrees Celsius or -315 degrees Fahrenheit.
26. Ganymede has an interesting feature. It has polar ice caps. This is caused by its magnetic field and scientists say that when ice interacts with the charged particles of the magnetosphere (or the plasma), it is channeled down, forming a frost layer on the poles.
27. Ganymede also has an atmosphere which is primarily oxygen. However, the atmosphere is way too thin to support any life. The oxygen that forms the atmosphere is more likely formed when water molecules from surface ice is broken down into hydrogen and oxygen atoms. This breaking down takes place because of solar radiations. The lighter hydrogen escapes while the heavier oxygen hangs around.
28. The cratered and dark terrain which covers 40% of Ganymede’s surface is thought to be made up of organic matter and clay.
29. Scientists hypothesize that darker region was formed by comet and asteroid impacts some 4 billion years ago. The lighter region, according to scientists, is far younger. Scientists believe that Ganymede itself is 4.5 billion years old.
30. Several spacecrafts have visited this interesting moon of Jupiter. The first one was Pioneer 10 (1973) followed by Pioneer 11 (1974), followed by Voyager 1 and Voyager 2 and finally Galileo. Galileo was the one that went extremely close to Ganymede’s surface. It hovered at a height of 162 miles from the surface and captured some striking photographs.