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The estimated time until a gamma-ray burst, or massive, hyperenergetic supernova, occurs within 6,500 light-years of Earth; close enough for its rays to affect Earth's ozone layer and potentially trigger a mass extinction, assuming the hypothesis is correct that a previous such explosion triggered the Ordovician–Silurian extinction 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]
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
In order to have a significant effect on atmospheric escape, the radius of the impacting body must be larger than the scale height. The projectile can impart momentum, and thereby facilitate escape of the atmosphere, in three main ways: (a) the meteoroid heats and accelerates the gas it encounters as it travels through the atmosphere, (b) solid ...
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.
NASA is on high alert for a “city-killer” asteroid that’s headed toward Earth — cuz they don’t wanna miss a thing. The asteroid, called 2024 YR4, now has a 1.5% probability of hitting ...
Most won't make the deadline. The U.N. says that's OK as long as they are working on them. So far only a dozen of the 195 nations that signed the 2015 Paris climate agreement have filed their ...
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 ...