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  2. Great Oxidation Event - Wikipedia

    en.wikipedia.org/wiki/Great_Oxidation_Event

    Oxygen, O 2, meanwhile, was present in the atmosphere at just 0.001% of its present atmospheric level. [12] [13] The Sun shone at about 70% of its current brightness 4 billion years ago, but there is strong evidence that liquid water existed on Earth at the time. A warm Earth, in spite of a faint Sun, is known as the faint young Sun paradox. [14]

  3. Geological history of oxygen - Wikipedia

    en.wikipedia.org/wiki/Geological_history_of_oxygen

    The increase in oxygen concentrations had wide ranging and significant impacts on Earth's biosphere. Most significantly, the rise of oxygen and the oxidative depletion of greenhouse gases (especially atmospheric methane ) due to the GOE led to an icehouse Earth that caused a mass extinction of anaerobic microbes , but paved the way for the ...

  4. Future of Earth - Wikipedia

    en.wikipedia.org/wiki/Future_of_Earth

    The ablation and vaporization caused by Earth's fall on a decaying trajectory towards the Sun may remove Earth's mantle, leaving just the core, which will finally be destroyed after at most 200 years. [102] [103] Earth's sole legacy will be a very slight increase (0.01%) of the solar metallicity following this event. [104]: IIC

  5. Ozone–oxygen cycle - Wikipedia

    en.wikipedia.org/wiki/Ozone–oxygen_cycle

    If an oxygen atom and an ozone molecule meet, they recombine to form two oxygen molecules: 4. ozone conversion: O 3 + O → 2 O 2. Two oxygen atoms may react to form one oxygen molecule: 5. oxygen recombination: 2O + A → O 2 + A as in reaction 2 (above), A denotes another molecule or atom, like N 2 or O 2 required for the conservation of ...

  6. Oxygen cycle - Wikipedia

    en.wikipedia.org/wiki/Oxygen_cycle

    The Earth's atmosphere, hydrosphere, and biosphere together hold less than 0.05% of the Earth's total mass of oxygen. Besides O 2, additional oxygen atoms are present in various forms spread throughout the surface reservoirs in the molecules of biomass, H 2 O, CO 2, HNO 3, NO, NO 2, CO, H 2 O 2, O 3, SO 2, H 2 SO 4, MgO, CaO, Al2O3, SiO 2, and ...

  7. How to make oxygen on the moon - AOL

    www.aol.com/finance/oxygen-moon-000221275.html

    Luckily, the lunar regolith is full of metal oxides. But while the science of extracting oxygen from metal oxides, for example, is well understood on Earth, doing this on the moon is much harder.

  8. Doomsday device - Wikipedia

    en.wikipedia.org/wiki/Doomsday_Device

    Many hypothetical doomsday devices are based on salted hydrogen bombs creating large amounts of nuclear fallout.. A doomsday device is a hypothetical construction – usually a weapon or weapons system – which could destroy all life on a planet, particularly Earth, or destroy the planet itself, bringing "doomsday", a term used for the end of planet Earth.

  9. Doomsday clock ticks down, closest ever to "global catastrophe"

    www.aol.com/doomsday-clock-ticks-down-closest...

    The Doomsday clock was set at 89 seconds to midnight on Tuesday morning, putting it the closest the world has ever been to what scientists deem "global catastrophe."