Alien life is common in universe

Alien life in the universe may be much more common than thought, say scientists who analysed the oldest known fossil microorganisms which indicate that life on Earth began as far back as 3.5 million years ago.

Scientists from University of California, Los Angeles and the University of Wisconsin-Madison in the US found that two of the species they studied performed a primitive form of photosynthesis, another produced methane gas, and two others consumed methane and used it to build their cell walls.

The microorganisms, from Western Australia, are 3.465 billion years old. The evidence that a diverse group of organisms had already evolved extremely early in the Earth’s history strengthens the case for life existing elsewhere in the universe.

This is because it would be extremely unlikely that life formed quickly on Earth but did not arise anywhere else. “By 3.465 billion years ago, life was already diverse on Earth; that’s clear – primitive photosynthesizers, methane producers, methane users,” said J William Schopf, professor at UCLA.

"These are the first data that show the very diverse organisms at that time in Earth's history, and our previous research has shown that there were sulfur users 3.4 billion years ago as well," said Schopf, lead author of the study published in the journal PNAS.