This era begins with the formation of the Solar System and Earth, outgassing of first atmosphere and oceans, bombardment by left-over planetessimals and debris. The name says it all; a hellish period lasting some 760 million years, when the Earth was subject to frequent bombardment by comets, asteroids, and other planetary debris. At one point, early in this era the moon was formed when a Mars-sized body struck the original Earth, pulverizing both. Yet incredibly, the first primitive life emerged even at this early stage. This was an era characterized by extensive volcanism and formation of first continents. By the end of the Hadean, the Earth had an atmosphere (unbreathable to most organisms today), and oceans filled with prokaryote life evolution ........ the begining got it ! lets see what next era is in my next blog !