Get flash to fully experience Pearltrees
Could ancient civilizations have harnessed the power of the atom? What about advanced aircraft capable of out-maneuvering our best jet-propelled planes?
The lunar geological timescale (or selenological timescale ) divides the history of Earth 's Moon into five generally recognized periods: the Copernican , Eratosthenian , Imbrian ( Late and Early epochs), Nectarian , and Pre-Nectarian . The boundaries of this time scale are related to large impact events that have modified the lunar surface , changes in crater form that occur through time, and the size-frequency distribution of craters superposed on geological units.
Known objects in the Kuiper belt, derived from data from the Minor Planet Center .
The Hubble Extreme Deep Field (XDF) was completed in September 2012 and shows the farthest galaxies ever photographed by humans. Each speck of light in the photo is an individual galaxy, some of them as old as 13.2 billion years; the observable universe is estimated to contain more than 200 billion galaxies.
Iron Man 2 opens today! Are you excited? Really? Huh. Well, keep reading anyway.