Up to half of Earth’s water is older than the Sun. Much of the water on our planet and around the solar system started out as tiny grains of ice floating in interstellar space. Ice found between stars is deuterium-rich, and apparently most of it made its way to Earth's on ice-rich comets that collided with our planet billions of years ago.
Asteroids that slammed into Earth and the moon more than 4 billion years ago were vaporized into a mist of iron. A cloud of iron mist will have wrapped around the globe after any such collision, falling to Earth as metal rain. The iron mist thrown up from the high-velocity impacts of these asteroids traveled fast enough to escape the moon’s gravity but stayed gravitationally stuck on more massive Earth. This may help explain why the chemistry of the Earth and the moon differ.
Evidence of living organisms contemporary with the Hadean-eon formation of the Earth was recently discovered in Western Australian, dating nearly 1 billion years before the current fossil record. Scientists discovered 4.1 billion-year-old zircon samples (before even oceans appeared on earth) that had pockets of organic carbon. Some scientists even speculate that life itself is older than the earth, suggesting that life first appeared about 10 billion years ago, which is far older than the Earth’s projected age of 4.5 billion years.
Earth's oceans formed billions of years ago over vast periods of time. The water remained a gas until the Earth cooled below 212 degrees Fahrenheit. At this time, around 4.4 billion years ago, the water condensed into rain which filled the basins that are now our oceans.
5Life on Earth
Life most likely emerged on Earth almost instantaneously after becoming habitable. The first oceans formed 4.4 billion years ago, whereas current evidence supports the first life to have formed 4.28 billion years ago. Instantaneous of course means on a geological timescale here.
6Earliest Life Forms
The earliest known life-forms on Earth are fossilized micro-organisms, found in hydrothermal vent holes in the seafloor. These were most probably chemosynthetic bacteria. These bacteria use sulfur compounds, particularly hydrogen sulfide, a chemical highly toxic to most known organisms, to produce organic material. Scientists have also recently found that hydrothermal vents at the bottom of the ocean are hot enough to emit enough light (mostly in the infrared spectrum) to support photosynthetic bacteria.
The vast majority of the Earth's gold and other heavy metals are locked up in the earth's core. Evidence from tungsten isotope studies indicates that most gold in the crust is derived from gold in the mantle which resulted from a meteorite bombardment some 3.9 billion years ago.
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Purple Earth hypothesis suggests that early life forms on Earth may have been able to generate metabolic energy from sunlight using a purple-pigmented molecule called retinal that possibly predates the evolution of chlorophyll and photosynthesis. As a consequence, early Earth’s landmass may have looked purple.
Recent studies have suggested that photosynthesis may have begun about 3.4 billion years ago. But before photosynthetic organisms developed, the earth might have not been a blue planet at all. The unoxidized iron in the ocean might have given it a dark green or even black color. Then as photosynthesis ramped up, it would have turned the oceans red as the iron oxidized and the earth became a blue planet as the dissolved iron oxide precipitated to the bottom.
As many as six supercontinents are thought to have formed and broken up prior to Pangaea. Roughly 400 million years pass between each repetition of the supercontinent cycle, which is currently causing the Pacific Ocean to shrink until yet another supercontinent will someday be formed. The oldest supercontinent on earth is Vaalbara which formed 2.7 to 3.6 billion years ago.