The world's oldest known fossil, dating back 3.7 billion years, has been found in Greenland. Scientists have announced that the fossil, which dates back to when asteroids were all over, will have "staggering" implications. Rocks that were recently exposed after the snow melted contained stromatolites, sediments that researchers conclude had been created by the growth of multiple layers of micro-organisms.
If this is confirmed as evidence of life, then they will be 220 million years older than the previous record-holder. It is also extremely sophisticated.
A NASA expert said that if fossils were evidence of living creatures, then this showed that “life is not a fussy, reluctant and unlikely thing,” which increases the chances that it will have developed on Mars or somewhere else in the Universe.
Dr. Abigail Allwood of NASA's Jet Propulsion Laboratory said that while there aren't actually fossilized organic remains, the rocks did contain “fairly credible hallmarks of microbial activity”.
Researcher from Australia and the UK wrote in Nature about the stromatolites, saying that they grew “in a shallow marine environment” in what is now Isua, south-west Greenland. “The stromatolites predate by 220 million years the previous most convincing and generally accepted evidence for oldest life remains in the 3,480 million-year-old Dresser Formation of the Pilbara Craton, Australia,” they added.
They also suggested that the “sophistication of life” some 3.7 billion years ago was “in accord with genetic molecular clock studies placing life’s origin in the Hadean eon,” which was more than four billion years ago. Many people believe that earth was only formed 4.6 billion years ago.
They have said that there was an “equable climate” at the time despite the “the faint young Sun,” which suggests that there was a difference in the amounts of carbon dioxide and/or methane.
Dr. Allwood said that the discovery could lead to answers about what happened at the dawn of earth. “Did life on this planet begin only after a relatively long planetary evolution, until suitable environments emerged that allowed life to gain a toehold, or was the cradle of life ready and rocking when Earth itself was but an infant?” she wrote.
The rocks show signs of activity such as “ancient ripple marks and piles of rock fragments deposited during an ancient storm,” according to Dr. Allwood. She did caution that there would be some disagreement about what the fossil symbolize.
“The discovery … will no doubt also spark controversy,” Dr. Allwood wrote. “There are no organic or cellular remains … [but there] are fairly credible hallmarks of microbial activity.”
“If these are really the figurative tombstones of our earliest ancestors, the implications are staggering,” Dr. Allwood wrote. “Earth’s surface 3.7 billion years ago was a tumultuous place, bombarded by asteroids and still in its formative stages.