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Abiogenesis. Stages in the origin of life range from the well-understood, such as the habitable Earth and the abiotic synthesis of simple molecules, to the largely unknown, like the derivation of the last universal common ancestor (LUCA) with its complex molecular functionalities. [1]
Panspermia is the hypothesis that life exists throughout the universe, distributed by meteoroids, asteroids, comets [1] and planetoids. [2] It does not attempt to explain how life originated, but shifts the origin to another heavenly body. The advantage is that life is not required to have formed on each planet it occurs on, but rather in a ...
Many alternative abiogenesis scenarios have been proposed by scientists in a variety of fields from the 1950s onwards in an attempt to explain how the complex mechanisms of life could have come into existence. These include hypothesized ancient environments that might have been favourable for the origin of life, and possible biochemical mechanisms.
UV and abiogenesis. UV light is considered a key component of prebiotic chemistry on an early Earth. Because of their short wavelengths (10-400 nanometers), UV photons carry enough energy to effect the electronic structure of molecules by interacting with molecular bonds by breaking them (), ionizing them (photoionization), or exciting their electrons (photoexcitation).
Warm little pond. A warm little pond is a hypothetical terrestrial shallow water environment on early Earth under which the origin of life could have occurred. The term was originally coined by Charles Darwin in an 1871 letter to his friend Joseph Dalton Hooker. [1][2] This idea is related to later work such as the Oparin-Haldane hypothesis and ...
The earliest known life forms on Earth may be as old as 4.1 billion years (or Ga) according to biologically fractionated graphite inside a single zircon grain in the Jack Hills range of Australia. [2] The earliest evidence of life found in a stratigraphic unit, not just a single mineral grain, is the 3.7 Ga metasedimentary rocks containing ...
Great Filter. The Great Filter is the idea that, in the development of life from the earliest stages of abiogenesis to reaching the highest levels of development on the Kardashev scale, there is a barrier to development that makes detectable extraterrestrial life exceedingly rare. [1][2] The Great Filter is one possible resolution of the Fermi ...
The Miller–Urey experiment was a synthesis of small organic molecules in a mixture of simple gases in a thermal gradient created by heating (right) and cooling (left) the mixture at the same time, with electrical discharges. The Miller–Urey experiment, [1] or Miller experiment, [2] was an experiment in chemical synthesis carried out in 1952 ...