Reacción a "What could be the first exomoon orbiting a brown dwarf has been discovered"

Detecting an exomoon for the first time (that is, observing that planets in other stellar systems have their own moons) is a milestone of enormous significance in astronomy. On the one hand, because it would tell us that we do not have to wait for future technology or undertake interstellar travel, but that we can observe them now. And on the other, because it would help us understand how planetary systems form. The significance is comparable to that of the wave of discoveries that followed the start of the exoplanet discovery race, which has helped us understand not only that planet formation is far more common than we thought, but also that the architecture of our solar system—with small planets orbiting closer to the star and giant planets orbiting further out—is not exactly ‘normal’ in other stellar systems.

However, the authors admit that they are not sure whether they can categorically state that this body can be called an ‘exomoon’, as it is almost as large as Jupiter and orbits a brown dwarf (which is something halfway between a planet and a star). Nevertheless, I believe that it is precisely this uncertainty that highlights the significance of the discovery made by Kevin Hoy and his team: the observation of a body that challenges our understanding of what we can call a ‘moon’. Something similar happened when it was discovered that the dwarf planet Pluto had a moon, Charon, which was far too large and massive for what moons are usually like in comparison to the planets they orbit. Sometimes, discovering something unexpected is even more exciting than finding what you were looking for in the first place. Above all, because it forces us to rethink everything we know.