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11 maj 2023 · Our Sun formed about 4.57 billion years ago from a cloud of collapsing dust and gas, in an unremarkable corner of the Milky Way galaxy. The material left over the Sun’s formation coalesced into everything else in our Solar System, including Earth, which was born around 4.55 billion years ago.
21 sie 2019 · That process leaves what's known as oxygen-16 nucleus, which decays and becomes what is found in solar wind and 99.762 percent of oxygen on Earth.
Geological history of oxygen. Although oxygen is the most abundant element in Earth's crust, due to its high reactivity it mostly exists in compound (oxide) forms such as water, carbon dioxide, iron oxides and silicates. Before photosynthesis evolved, Earth's atmosphere had no free diatomic elemental oxygen (O 2). [2]
At some point early in the game, perhaps within hundreds of millions of years of Earth's formation, a mechanism for pulling energy provided by sunlight from certain chemicals was chanced upon. Though it was technically photosynthesis, it wasn't the kind that left an excess of oxygen.
12 gru 2022 · On modern Earth, the dominant tectonic activity is called plate tectonics, where oceanic crust — the outermost layer of Earth under the oceans — sinks into Earth’s mantle (the area between...
19 sie 2009 · So how did Earth end up with an atmosphere made up of roughly 21 percent of the stuff? The answer is tiny organisms known as cyanobacteria, or blue-green algae.
12 wrz 2008 · The most abundant oxygen-bearing molecule in the solar nebula was carbon monoxide, CO, and self-shielding has been considered a key to the relative amounts of oxygen that result when CO is dissociated by vacuum ultraviolet light, or VUV. (VUV refers to wavelengths from 200 to 10 nanometers.)
