Turns out we might not need that interstellar space rock to prove aliens exist after all, as scientists have found ‘strong’ evidence they say confirms the likelihood of life elsewhere in the universe.
And they didn’t even have to leave Earth.
Looking at ancient fossil microorganisms dug up in Australia – that are a phenomenal 3.465 billion years old (the oldest known examples we have) – the team say they couldn’t help but conclude that we are not alone in our universe.
The average lifetime of a rock exposed on the surface of the Earth is about 200 million years, says Professor J. William Schopf, adding that when he began his career, there was no fossil evidence of life dating back more than 500 million years ago.
But the rocks in this study, “are about as far back as rocks go,” says Schopf.
There are several pieces of evidence that lead the team, from the UCLA and University of Wisconsin, to this conclusion.
The first is that the fossilized species seemed to have performed a primitive form of photosynthesis, another apparently produced methane gas, and two others appear to have consumed methane and used it to build their cell walls.
Primitive photosynthesizers of this nature are fairly rare on Earth today because they exist only in places where there is light but no oxygen ― normally there is abundant oxygen anywhere there is light.
Their ability to perform these different functions mean they have evolved extremely early in Earth’s history: “These are the first data that show the very diverse organisms at that time in Earth’s history,” says Schopf.
“This tells us life had to have begun substantially earlier and it confirms that it was not difficult for primitive life to form and to evolve into more advanced microorganisms.”
This evidence combined with scientists increasing knowledge of the vast number of stars in the universe and that planets orbit so many of them undoubtedly strengthens the case for life existing elsewhere in the universe.
In short, it would be extremely unlikely that life formed quickly here and not elsewhere.
The study is the most detailed ever conducted on microorganisms preserved in such ancient fossils.
Researchers led by Schopf first described the fossils in the journal Science in 1993, and then substantiated their biological origin in the journal Nature in 2002.