An article published in the journal “Science Advances” presents the evidence of the existence of a exomoon, a moon orbiting a planet of another solar system, named Kepler-1625b-I. David Kipping and Alex Teachey of Columbia University used observations of the Kepler and Hubble space telescopes to examine the traces left by the exoplanet Kepler-1625b in front of its star, similar to the Sun. The first indications of the discovery of the exomoon candidate were revealed in July 2017, follow-up observations carried out with the Hubble Space Telescope provided new confirmations.