New research suggests that microscopic fossils found in a 3.5-billion-year-old piece of rock from Western Australia are the oldest evidence of life on Earth. Some of them were primitive photosynthesizers while others were producers of methane.
The research shows that it is not so hard for life to form and that some microorganism managed to live in places and environments that were considered to be unlivable. Researchers are trying to know more about the nature of these tiny microscopic fossils. They say that if they could live in such inhospitable environment, then there is the chance that life could exist all over the universe.
“This tells us life had to have begun substantially earlier and it confirms that it was not difficult for primitive life to form,” said lead author and UCLA paleobiology professor J. William Schopf, in a statement about the research, adding that scientists can’t yet be sure how much earlier life may have actually begun on Earth. “But, if the conditions are right, it looks like life in the universe should be widespread.”
What are these microscopic organisms?
These tiny microorganisms would likely die if they were in today’s atmosphere because they would be poisoned by the quantity of oxygen that exists nowadays. Researchers realized that these old tiny fossils were different.
They are thought to live where there was little to no oxygen, which is similar to the surface of Mars and other planets. The researchers also found that they were methane users which leads to thinking that there could be life in Saturn’s moon Titan, since it may be covered with vast seas of liquid methane.
These organisms lived on the surface of the Earth about 3.5 billion years ago when the conditions of the planet were utterly unpleasant. No oxygen, high chances of being attacked by giant asteroids and frequent volcanic eruptions. Even so, diverse organisms adapted to such conditions.
This suggests abiogenesis, which is the start of life from no-life. Scientists consider that these little organisms might have been the product of a billion years of evolution. The Earth is thought to be about 4.5 billion years old. By that time the Earth was in the Hadean or “hellish” period, and the atmosphere contained helium and hydrogen, with no free oxygen, and it was too hot for water or ice to form.
“We have no direct evidence that life existed 4.3 billion years ago but there is no reason why it couldn’t have,” study co-author John W. Valley aid in the statement. “This is something we all would like to find out,” Valley added. He is a professor of geoscience at the University of Wisconsin-Madison.
The findings were published Monday in the Proceedings of the National Academy of Sciences. The study was conducted by researchers from the University of California, Los Angeles, and the University of Wisconsin.
These microfossils were unearthed in Western Australia in 1982 and described for the first time in 1993. They can’t be viewed with the naked eye. Eight of them lined up one after the other would be as thick as a human hair. At first, scientists debated whether or not they were actual organisms since a lot of them considered that they were just strange minerals.
Other planets might host this kind of life
If this life evolved on Earth just after forming and when there was practically nothing on its surface to live with, then there is a possibility that other planets, where the conditions are as extreme as the ones we had on Earth back then, could host this sort of life. That is what the astrobiologists want to know.
They are the ones that study the possibility of non-intelligent extraterrestrial life. They study and try to understand in which part of the universe life might evolve based on what we have found down here, on planet Earth. That is because a lot of planets have similar elements and conditions as Earth’s.
For example, the extremophiles, are organisms that live in extreme conditions with temperatures and levels or chemicals unsustainable by the human body or by most living beings. If those microorganisms can live like that, then it is logical to think that somewhere else in the universe similar organisms might inhabit planets where the conditions are extreme.
William Schopf, director of UCLA’s Center for the Study of Evolution and the Origin of Life, said that given these results then he considerers that life could be more abundant in our solar system or beyond that it was though.
NASA has a large and vital division dedicated to astrobiology. The researchers try to understand why Earth is habitable to know how other places outside our planet could also be.
Source: Newsweek