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
Union of the Sun and Moon be assured a rebirth in a natural nirmanakaya realm during the bardo of becoming and there reveal buddhahood without further rebirths." Namkha'i and Shane (1986, 1999: p. 91) open the discourse of the 'Song of the Vajra' (Wylie: rdo rje'i glu zhig) an excerpt of the "Union of the Sun and Moon" into the English language and render it thus: <poem> Union of the Sun and Moon The Union of the Sun and Moon () is one of the Seventeen tantras of the esoteric instruction cycle () which are a suite of tantras known variously as: Nyingtik, Upadesha or Menngagde