If you were stargazing on Mars, you could watch the dance of the Earth & Moon in your evening sky. ESA's Mars Express just made a little sped-up movie of what you'd see. (Both Earth & Moon would be easily visible to the naked eye.) https://www.esa.int/Science_Exploration/Space_Science/Mars_Express/Earth_and_Moon_seen_from_Mars #science #space #astrodon