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In astronomy, extinction is the absorption and scattering of electromagnetic radiation by dust and gas between an emitting astronomical object and the observer. Interstellar extinction was first documented as such in 1930 by Robert Julius Trumpler .
Dust grains in the ISM are responsible for extinction and reddening, the decreasing light intensity and shift in the dominant observable wavelengths of light from a star. These effects are caused by scattering and absorption of photons and allow the ISM to be observed with the naked eye in a dark sky.
This may be self-evident, since a gamma-ray burst in the Milky Way pointed directly at Earth would likely sterilize the planet or effect a mass extinction. [13] The Late Ordovician mass extinction has been hypothesised by some researchers to have occurred as a result of such a gamma-ray burst. [14] [15] [16]
One, in the journal Nature Astronomy, found that the samples contained a diverse mixture of organic compounds. And the other, in the journal Nature, found that the samples contained minerals ...
The Siberian Traps was a vast area of volcanic activity in Eurasia that led to the biggest mass extinction 252 million years ago. The distant mountains are remains of basalt lava flows, and the ...
The work caught the attention of NASA, which has a longstanding interest in understanding the factors that compel evolution and extinction on this planet — and, potentially, on others.
The Shiva hypothesis, also known as coherent catastrophism, is the idea that global natural catastrophes on Earth, such as extinction events, happen at regular intervals because of the periodic motion of the Sun in relation to the Milky Way galaxy.
Nemesis is a hypothetical red dwarf [1] or brown dwarf, [2] originally postulated in 1984 [3] to be orbiting the Sun at a distance of about 95,000 AU (1.5 light-years), [2] somewhat beyond the Oort cloud, to explain a perceived cycle of mass extinctions in the geological record, which seem to occur more often at intervals of 26 million years.