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) for the Moon was the Silver Flower, and Gollum referred to it as the White Face. The Moon was more highly valued than the Sun by the Elves, both because it came from the Elder Tree, and because it rose first. In the universe of Middle-earth, the Moon was generally regarded as masculine, in recognition of Tilion. This gender corresponds with Máni, the personified moon in Norse mythology. In the early versions of "The Silmarillion" as described in "The Book of Lost Tales 1", a part of The History of Middle-earth series, the Sun was described in great detail as