The Formation of Earth
Proto-Earth forms as a ball of molten rock from dust, ice, and other materials orbiting the Sun. All the raw materials and energy needed for life are present, but its emergence will have to wait until conditions improve and stabilize.
The Primordial Planet grows larger as it sweeps up planetesimals and other small objects orbiting the Sun. It spins much more rapidly than now: a day lasts only four or five hours.
A Cataclysmic Collision with a Mars-sized planet vaporizes Earth’s outer layer and produces a huge cloud of debris that orbits the Earth. The debris coalesces to form the Moon—which, orbiting very close to Earth, produces huge tides and giant storms in newly formed oceans. Giant meteors then pelt the planet, creating clouds of debris that block warmth and light from the Sun.
Under Earth’s thin crust, convection currents in molten material known as the mantle produce violent volcanic eruptions. Vast amounts of heat from Earth’s interior are released, and the atmosphere is filled with carbon dioxide.
In the Oceans, carbon dioxide from the atmosphere accumulates. It reacts with hydrogen escaping from inside Earth to produce more water—along with methane, acetic acid, and other, more complex molecules essential to life.
On the ocean floor, hydrothermal vents emit steaming-hot water saturated with dissolved minerals. This leads to the accumulation of other chemicals necessary for life, including nitrogen in the form of ammonia, sulfides, phosphates, and trace amounts of transition metals such as iron, nickel, manganese, cobalt, and zinc.
Violent Forces break the surface of the Earth into tectonic plates, but on the ocean floor, warm sediments and permeable rock (mainly basalt) provide environments where the first living things may emerge to subsist on a diet of inorganic chemicals like the microbial life that flourishes there today.
Continuing convection currents in the mantle generate massive collisions between the tectonic plates. As surface material slides back down into the mantle, portions of the ocean floor are uplifted to form coastal shallows.
Most organisms taking the ride from the ocean floor to the coastal shallows are killed, but some lucky colonies of bacteria may survive and find themselves positioned perfectly—deep enough to be protected from dangerous solar radiation but shallow enough to use it for energy as the process of photosynthesis evolves. Atmospheric oxygen produced by photosynthesizing bacteria over millions of years gives our planet the blue-green cast it has today.