Scientists Discover Life Proof of 3.95 Billion Years on Earth

Rudimentary life may have existed on Earth 3.95 billion years ago, when our baby planet was bombarded by comets and barely oxygenated, scientists said last week. A team led by Takayuki Tashiro and Tsuyoshi Komiya presented what they call the oldest known fossil evidence to live in Graphite Blue Planet, a form of carbon, sandwiched in ancient sedimentary rocks in Labrador, Canada.

The earliest life footprint was previously reported in March, from a location in Quebec estimated to be between 3.8 billion and 4.3 billion years old, although a new study author has called the discovery process "highly controversial."

"This is the oldest evidence," said Tsuyoshi Komiya of the University of Tokyo insisted in an email exchange with AFP. "Our samples are also the oldest supracrustal rocks stored on Earth."

The sample is similar to a formation containing a Quebec sample. Fossil evidence for early organisms and rocks remaining from that period is often poorly maintained.

The main difficulty of scientists in trying to find the oldest life on Earth proves that organic waste is produced by living organisms rather than geological processes.

This study is aimed not only to determine the beginnings of life on our planet, but also to explain the possibilities of life that exist or still exist on other planets such as Mars. For this new study, Komiya and the team studied graphite, a form of carbon used on the tip of a pencil, on rocks in the Saglek Block in Labrador, Canada.

They measured the isotopic composition, the chemical element mark, and concluded the graphite was biogenic which means produced by living organisms. The identity of the organism, or what it looks like, remains a mystery.

"We will analyze other isotopes such as nitrogen, sulfur and iron from organic matter and minerals to identify the types of organisms," Komiya said of the next step.

In addition, we can estimate the environment in which organisms live by analyzing the chemical composition of the rock itself.

If these findings are accurate, it means life began on Earth just a second geologic after its formation some 4.5 billion years ago. Prior to the Quebec fossil, which is also described in Nature, the earliest life trail discovered scientists in Greenland and dated 3.7 billion years ago. 

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