Comparative planetary science closest analogue is the Pluto-Charon system, though its axial tilt is completely different. Both our Moon and Charon are hypothesized to have formed via giant impacts. Giant impacts are hypothesized to account for both the tilt of Uranus, and the retrograde rotation of Venus. Giant impacts are also candidates for the Mars ocean hypothesis, and the high density of Mercury. Most giant planets (except Neptune) have retinues of moons, rings, ring shepherds, and moon Trojans analogous to mini-solar systems. These systems are postulated to have accreted from analogous gas clouds, and possibly with analogous migrations during their formation periods. The
Solar eclipses on Uranus Solar eclipses on Uranus Solar eclipses on Uranus occur when any of the natural satellites of Uranus passes in front of the Sun as seen from Uranus. Eclipses can occur only near a solar ring plane-crossing of Uranus (equinox), occurring approximately every 42 years, with the last crossing being in 2007/2008. For bodies that appear smaller in angular diameter than the Sun, the proper term would be a transit and bodies that are larger than the apparent size of the Sun, the proper term would be an occultation. Twelve satellites of Uranus—Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Puck, Miranda, Ariel,