... Verona Rupes: Tallest Known Cliff in the Solar System . ... Verona Rupes on Uranus' moon Miranda is estimated to be 20 kilometers deep -- ten times the depth of the Earth's Grand Canyon. ... Over 400,000 light years across NGC 6872 is an enormous spiral galaxy, at least 4 times the size of our own, very large, Milky Way. ... Named Valles Marineris, the grand valley extends over 3,000 kilometers long, spans as much as 600 kilometers across, and delves as much as 8 kilometers deep. ...