Formation and evolution of the Solar System impact event, the Tunguska event, the Chelyabinsk meteor and the impact feature Meteor Crater in Arizona. The process of accretion, therefore, is not complete, and may still pose a threat to life on Earth. Over the course of the Solar System's evolution, comets were ejected out of the inner Solar System by the gravity of the giant planets, and sent thousands of AU outward to form the Oort cloud, a spherical outer swarm of cometary nuclei at the farthest extent of the Sun's gravitational pull. Eventually, after about 800 million years, the gravitational disruption caused by galactic tides, passing stars
Sun and Moon (Middle-earth) the Elven lore, as presented in the legendarium of "The Silmarillion", the Man in the Moon of the Hobbits' tales must have his origins in the legend of Tilion the Maia. In The Book of Lost Tales, his name is given as Uolë Kúvion, but the tale of how he came to live there was never fully told. Sun and Moon (Middle-earth) The fantasy author J. R. R. Tolkien of Middle-earth fame included Earth's sun and moon for the cosmology of his myths of Arda. These astronomical bodies appear in various versions of "The Silmarillion", a history of a world,