Astronomers from the University of Geneva (UNIGE), Switzerland and collaborators used the Hubble Space Telescope to study an exoplanet that had been observed losing its atmosphere, forming an enormous cloud of hydrogen and giving the planet the appearance of a giant comet. During earlier observations in 2015, it was not possible to observe the whole cloud, whose shape was predicted by numerical simulations. Thanks to these new observations, however, the scientists have finally been able to confirm the initial predictions. The results are unveiled in the journal Astronomy & Astrophysics.