Meteorites could have brought all 5 genetic 'letters' of DNA to early Earth


Oct 22, 2019
"Key building blocks of DNA that previous research mysteriously failed to discover in meteorites have now been discovered in space rocks, suggesting that cosmic impacts might once have helped deliver these vital ingredients of life to ancient Earth."

Very interesting. Most meteorite radiometric ages are about 4.56 to 4.59 billion years old. This report indicates life likely flourishing on Earth some 4.28 billion years ago. Diverse life forms may have evolved earlier than previously thought,

"Diverse microbial life existed on Earth at least 3.75 billion years ago, suggests a new study led by UCL researchers that challenges the conventional view of when life began. For the study, published in Science Advances, the research team analyzed a fist-sized rock from Quebec, Canada, estimated to be between 3.75 and 4.28 billion years old."

How did the DNA molecules survive the impacts and formation of early proto-earth and Theia to make the Moon? Do we have fossil record evidence for the survival process(es)? The age of the meteorites are at least 300 million years older than the oldest accepted ages for Earth rocks. It should be challenging to show how the DNA stuff delivered via impacts on what is likely a planetesimal and proto-earth, turned into the bacteria now dated some 4.28 billion years ago. Other reports indicate these bacteria are like those on Earth today too.

The reference paper states about bombardments, "A diverse suite of exogenous meteoritic organics, including nucleobases, may have been delivered to the early Earth during the late heavy bombardment period (~4.0–3.8 billion years ago);12,13 therefore, the influx of such organics is considered to have played an important role in the chemical evolution of the Earth’s primordial stage.",

This timeline avoids problems with Theia and proto-earth impacts, though the reports now indicate life on Earth flourishing 4.28 billion years ago earlier than this meteorite delivery DNA timeline. Other issues show up to with impacts delivering DNA to Earth that later evolves into life. Differences between the Moon's near and far sides linked to colossal ancient impact,, reports like this show still much heavy hitting taking place in the Earth-Moon system when life appears on Earth too.
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