* Astronomy

Soggy rocks hurtling through the solar system gave life on Earth an addiction to left-handed proteins, according to a new study. The research suggests that water on asteroids amplified left-handed amino acid molecules, making them dominate over their right-handed mirror images.
Curiously, almost every living organism on Earth uses left-handed amino acids instead of their right-handed counterparts. In the 1990s, scientists found that meteorites contain up to 15% more of the left version too. That suggests space rocks bombarding the early Earth biased its chemistry so that life used left-handed amino acids instead of right.

"Meteorites would have seeded the Earth with some of the prebiotic compounds like amino acids that are needed to get life started, and also biased the origin of life to the left-handed amino acid form" - Daniel Glavin at NASA's Goddard Space Flight Centre in Greenbelt, Maryland.

Some have suggested that polarised starlight preferentially destroyed right-handed amino acids on asteroids. But this alone couldn't explain why the meteorite bias is so strong.
Now Glavin and colleague Jason Dworkin have shown that water amplified the asymmetry.

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Scientists are puzzled as frozen life forms get exposed in the asteroids. The frozen life forms means the ingredients of life forms waiting for high velocity impact to form amino acids, the starting of the evolution cycle.
The association of the most abundant population of meteorites, the ordinary chondrites, and the S-type asteroids through the comparison of their reflected spectra in the visible and near infrared spectrum, is still widely debated.

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One of the most enduring questions is how life could have begun on Earth. Molecules that can make copies of themselves are thought to be crucial to understanding this process as they provide the basis for heritability, a critical characteristic of living systems. New findings could inform biochemical questions about how life began.
Now, a pair of Scripps Research Institute scientists has taken a significant step toward answering that question. The scientists have synthesized for the first time RNA enzymes that can replicate themselves without the help of any proteins or other cellular components, and the process proceeds indefinitely.
The work was recently published in the journal Science.
In the modern world, DNA carries the genetic sequence for advanced organisms, while RNA is dependent on DNA for performing its roles such as building proteins. But one prominent theory about the origins of life, called the RNA World model, postulates that because RNA can function as both a gene and an enzyme, RNA might have come before DNA and protein and acted as the ancestral molecule of life. However, the process of copying a genetic molecule, which is considered a basic qualification for life, appears to be exceedingly complex, involving many proteins and other cellular components.
For years, researchers have wondered whether there might be some simpler way to copy RNA, brought about by the RNA itself. Some tentative steps along this road had previously been taken by the Joyce lab and others, but no one could demonstrate that RNA replication could be self-propagating, that is, result in new copies of RNA that also could copy themselves.

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Japanese researchers have given us a new glimpse into the beginnings of life on Earth by recreating a meteoric collision into the sea to generate the building blocks of life, a British scientific journal reported Monday.
Hiromoto Nakazawa, fellow emeritus at the National Institute of Materials Science in Tsukuba, Ibaraki Prefecture, along with a research team at Tohoku University succeeded in recreating the moment a meteor crashes into the ocean, generating amino acid and other bioorganic molecules that comprise the basis of life.

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