There have been 1000’s of planets looked at though only a handful considered inhabitable. Well that number increases exponentially if you consider moons as a place to live as well.
We are planning on ‘living’ on our moon, so why not other moons?
Trying to understand why this is a new concept I looked up each in the dictionary afraid maybe there was something simple that I didn’t know. But no - A moon is quite simply a natural satellite revolving around a planet. A planet, on the other hand, is a body that orbits the Sun and is massive enough for its own gravity to make it round and has cleared its neighborhood of smaller objects around its orbit.
So it would seem that the definition that limits us is the one of planet, not the one of a moon. Actually a ‘planet’ such as Earth that were to have different circumstances could perhaps end up as the satellite instead.
The moons we know of are also loaded with resources; what could be the down side? Could it be an atmosphere? Titan (Saturn’s moon), Triton (Neptune’s moon), Io (Jupiter’s moon), Ganymede and Europa (also Jupiter’s moons) all have atmospheres. Why is an atmosphere important? Several reasons; one is filtering out radiation, then there is holding the surface heat of the planet, it gives us variations such as weather, and probably most important it protects us. Every day meteoroids enter our atmosphere but thanks to the friction in the air, they burn up. Okay so where is the problem?
The moon has a ‘Dark Side’ well; it doesn’t really have a dark side, just a side that never faces us. It is Tidal forces from Earth have slowed the rotation making it so that while it goes around us, the same side faces is always facing us. Dark Side is a misnomer Far Side is the correct nomenclature as it is not dark just out of our sight! Once we had achieved space flight thanks to the Russian spacecraftLuna 3 in 1959 and then the Russian probeZond 3 soon thereafter we got a chance to see what the ‘Dark Side’ actually was, a pile a dust and craters just like the side we see.
What else, Oxygen? Europa has oceans that offer more oxygen as a byproduct than Earth. Saturn’s moon Dione has the slightest bit of Oxygen. Our moon has FeTiO4 in the soil so oxygen is certainly accessible.
It would appear that the necessary things might not have anything to do with whether it is a planet or a moon but more whether it is hot or cold and other questions that might have more to do with our survival.