Despite their continuous efforts, researchers were unable to identify or find any exomoons until now, although they have found a large number of exoplanets. It seems that these tiny celestial bodies have simply been too small to detect with the technology we have at our disposal. However, this all may have changed now.
Astronomers used a Kepler Space Telescope to discover a Neptune sized moon which is orbiting a planet that is 4,000 light years away from Earth. The way they discovered this tiny body is because of the dip in brightness around the planet, which usually indicates a transient object. This is however still just speculation as nothing has been confirmed yet regardless of the promising data
For the time being, astronomers only have Kepler telescope data at their disposal. Before they make a concrete and final statement on this discovery, they want to review the data from the Hubble telescope. There is a very big chance that this object is indeed an alien moon, but there is also a distinct possibility that it is also simply another similar object which the telescope captured and it is not smart to rule out this possibility.
However, there will be plenty of people wondering what is so amazingly exciting in the discovery of an exomoon since we all know that moons are a fairly common celestial body. If not by observation, it should be clear that there are plenty of them in other systems simply through numbers of stars in galaxies.
This is all true. Nonetheless, the thing that is so interesting about this possible discovery is not really about the moon itself. If this exomoon is confirmed it will be a huge milestone for astronomers and the human race in general as it will change the way we study space.
Up until now, the scientists have been focusing on identifying the largest of objects but this might suggest that we are able to find and identify also the tiny celestial objects. This is clearly of the utmost importance as it indicates an increased chances for the sustainability of life, as moons stabilize rotation and shield from asteroids.