MARZIANI, PaolaPaolaMARZIANI2020-04-232020-04-2320152296-987Xhttp://hdl.handle.net/20.500.12386/24199This paper describes the framing of three challenges in Galactic and extra-galactic astronomy that can be legitimately called “grand:” the expansion of the redshift frontier, the census of galaxies and of their constituents with a full understanding of galactic evolution, and the study of accretion onto supermassive black holes in galactic nuclei, whose event horizon is literally a physical frontier of the Universe and where there is a potential for the development of new physics.ELETTRONICOenArticle10.3389/fspas.2015.000012-s2.0-85079376120000453947800001https://www.frontiersin.org/articles/10.3389/fspas.2015.00001/full2015FrASS...2....1MFIS/05 - ASTRONOMIA E ASTROFISICA