Retrograde and prograde motion with retrograde rotation – are Venus and Uranus. Venus's axial tilt is 177°, which means it is rotating almost exactly in the opposite direction to its orbit. Uranus has an axial tilt of 97.77°, so its axis of rotation is approximately parallel with the plane of the Solar System. The reason for Uranus's unusual axial tilt is not known with certainty, but the usual speculation is that during the formation of the Solar System, an Earth-sized protoplanet collided with Uranus, causing the skewed orientation. It is unlikely that Venus was formed with its present slow retrograde rotation, which takes 243
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,