Earth formed around 4.54 billion years ago, approx 1/3rd the age of universe by collisions in the giant disc-shaped cloud of material that also formed the Sun.
At initial there is no life, no oxygen, no land, no water on the Earth. There is only heat, burning floating lava's. Volcanic outgassing probably created the primordial atmosphere and then the ocean. The creation of Earth's Moon occurred due to the collision with a planet-sized body named Theiaed.
Over time, the Earth cooled, causing the formation of a solid crust, and allowing liquid water on the surface.
The following Archean and Proterozoic eons produced the beginnings of life on Earth and its earliest evolution. The succeeding eon is the Phanerozoic, divided into three eras: the Palaeozoic, an era of arthropods, fishes, and the first life on land; the Mesozoic, which spanned the rise, reign, and climactic extinction of the non-avian dinosaurs; and the Cenozoic, which saw the rise of mammals.
In 2012, researchers Michiel Lambrechts and Anders Johansen from Lund University in Sweden proposed that tiny pebbles, once written off, held the key to rapidly building giant planets.
"They showed that the leftover pebbles from this formation process, which previously were thought to be unimportant, could actually be a huge solution to the planet-forming problem," Levison said.
Levison and his team built on that research to model more precisely how the tiny pebbles could form planets seen in the galaxy today. While previous simulations, both large and medium-sized objects consumed their pebble-sized cousins at a relatively constant rate, Levison's simulations suggest that the larger objects acted more like bullies, snatching away pebbles from the mid-sized masses to grow at a far faster rate.
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