![060-Meteoric-Rain](thumbs/060-Meteoric-Rain.jpg)
![066-Moon-Capture-Theory](thumbs/066-Moon-Capture-Theory.jpg)
![297 - Early Earth](thumbs/297-Early-Earth.jpg)
![338-Proto-Planets](thumbs/338-Proto-Planets.jpg)
![340 - Comets Bring Water](thumbs/340-Comet-Flood.jpg)
![Protoplanetary Disk](thumbs/362-Solar-Nebula.jpg)
![380-Life-Cloud-Meteors](thumbs/380-Life-Cloud-Meteors.jpg)
![399-White-Dwarf-Collision](thumbs/399-White-Dwarf-Collision.jpg)
![400-Yucatan-Impact](slides/400-Yucatan-Impact.jpg)
400-Yucatan-Impact
An asteroid 5-10 miles across impacts in the Yucatan to end the age of dinosaurs 65 million years ago. A fine layer of clay, rich in the element iridium -- more concentrated in meteorites than in terrestrial rocks -- marks the geological boundary between the Cretaceous and Tertiary eras. This clay layer is believed to have precipitated out of a planet-blanketing cloud of dust that was ejected into the atmosphere by the impact and subsequent fires. The dust darkened and cooled the earth so much that many species became extinct.
![457-moon-capture-theory-diagram](slides/457-moon-capture-theory-diagram.jpg)
457-moon-capture-theory-diagram
Infographic shows processes for planet to aquire a satellite. A developing planet's halo of gas expands to capture a passing body (top). Its gravitational sphere of influence expands as well (middle). Interactions between passing asteroids may cause one to fall into orbit (bottom). Artwork © 2007 Don Dixon / cosmographica.com
![474-winter-solstice-diagram](thumbs/474-winter-solstice-diagram.jpg)
![475-end-of-cosmology](slides/475-end-of-cosmology.jpg)
475-end-of-cosmology
Diagram created for Scientific American depicting the view from earth in the far distant future, as the Milky Way and Andromeda Galaxy merge to create a giant elliptical galaxy. Ultimately, the last stars wink out and and the frozen cinder that is earth's surface is blasted smooth by a trillion years of micrometeorite bombardments. Only a few stars relieve the eternal night.