The very first space exploration missions were rather disappointing, considering that the only things we actually found were bland, colorless and inhospitable environments where life as we know it would be impossible. However, as the space shuttles dived further into the solar system, most scientists realized just how wrong they were.
At this point, there are over 200 natural satellites recorded in the solar system, some of which having incredible features and a remarkable diversity. In fact, some of these moons are so amazing that some researchers believe they can foster life. Let’s review 10 of the most fascinating natural satellites in the solar system.
While many scientists dub the second largest moon in the solar system as the Second Earth, looks can be deceiving. Even though Saturn’s natural satellite includes a dense atmosphere and it is mostly composed of nitrogen, Titan’s atmosphere also includes methane and ethane. Moreover, in spite of the fact that it is the only planetoids except Earth to contain liquid seas, lakes and oceans (deducted via the bright regions observed on its surface), they are actually composed of hydrocarbons and methane gases. Yet, many researchers believe that we will colonize Titan (even just for the purpose of harvesting Saturn’s resources) at one point or another.
According to our current knowledge, an object the size of Io should have been geologically inactive for quite some time now. Yet, the huge tidal friction from Jupiter as well as a few other natural satellites of the solar system’s giant (Europa and Ganymede) makes Io the most volcanic place in the solar system. As a matter of fact, the tidal friction exerted by Jupiter and its nearby moons create an enormous amount of heat that maintains Io’s surface constantly liquid (and renewable). Due to the tremendous eruptions, some of which rising as high as 190 miles, no space shuttle was able to examine the composition of the liquid surface of Io, although some assume it is mostly molten sulfur like in the atmosphere.
Europa represents the second celestial body in the solar system where scientists believe life would be possible. Perhaps the most distinguishable fact about Europa, its incredibly smooth surface is actually an ice crust hiding a huge ocean that spans throughout the entire surface. Similar to Io, this moon is affected by the tidal friction of Jupiter, an aspect that opens several discussions regarding the temperatures of the liquid. Considering that Europa also has an iron core (like Earth), you can understand where the speculations about extraterrestrial life on it come from.
With a diameter of 3,270 miles, Ganymede is actually larger than planet Mercury and gracefully holds the title of the largest moon of the solar system. At first glance, Ganymede does not impress much, considering that it looks pretty much like the Moon. However, the big difference between Ganymede and Moon consists of the fact that the former is so large that it has its own magnetic field. Because magnetic fields are associated with planets, many scientists have suggested that Jupiter’s moon is actually a planet. Well, if Ganymede were orbiting the Sun instead of Jupiter, then it would surely have been considered a planet.
Hiding deep inside Saturn’s inner rings, Enceladus is the only body in the solar system that reflects 100% of the light hitting its surface, making this moon the second brightest object after the Sun. Still, this is not the most interesting aspect of Enceladus. Observations show that its surface is subjected to major resurfacing events and that the Southern polar region contains massive geysers, which are the main source of the ice and dust particles of Saturn’s E ring.
Unlike the other famous moon of Jupiter, Callisto does not have any geological activity to coarsen its surface. In fact, this natural satellite is the only body in the solar system whose surface has remained unchanged for the past 4 billion years. The lack of regular resurfacing makes Callisto display a fascinating face, filled with a plethora of craters piling up one on top of each other. In order to get a clue about this phenomenon let’s just say that in some areas you can see concentric rings of craters within craters, a “crater-caption” if you will.
Triton is the largest moon of Neptune and surprisingly, it was noticed only about two weeks after the planet itself was discovered. The first thing that has captured attention of the scientists was the fact that this is the largest body to have a retrograde orbit. In other words, it rotates in the opposite direction of Neptune’s orbit, an element that suggests Triton is very likely to be a captured moon. However, the most captivating thing about Triton is the fact that it contains active (ice) volcanoes that are regularly spitting out water and ammonia.
Space represents the only place where anything is possible and Dactyl stands proof of that. Although the debate still carries on, the fact remains: Dactyl is currently the only natural satellite known to orbit an asteroid (Ida). Ever since its intriguing discovery in 1995, the smallest moon in the solar system has answered some of the important questions about the universe and it showed that even objects as small as Ida can have natural satellites.
Even though Miranda is considered one of the “ugliest” moons in the solar system, the natural satellite of Uranus has one of the most diversified landscapes we came across so far. Because it looks like a bunch of rocks and particles glued together in a hurry, numerous scientists believe that Miranda’s peculiar shape must be the result of a major collision that has torn the surface apart.
10. Epimetheus and Janus
Although nowadays they are considered two distinct moons of Saturn, the fact that they share the orbit so close together made astronomers believe that they were the same body a long time ago. However, this is not the thing that makes these little moons so fascinating, but rather the show they put on every four years when they switch places and come very close to each other, almost to the point of collision.