Life on Earth might be a lot less unusual than we thought, according to a new study.
For decades, researchers have believed in the “hard steps” theory of life, which suggests that we needed to go through a whole set of very unlikely events to get to the intelligent life that surrounds us today.
But the new study suggests it was not that unlikely or hard in the first place. In fact, it might have been relatively straightforward.
If so, that has important effects for life throughout the universe. It suggests that life might have been likely to form elsewhere, too – and that alien life could be waiting in more places than we thought.
The “hard steps” theory had suggested that life was probably rare: it would need a whole host of things to go right to begin.
“This is a significant shift in how we think about the history of life,” said Jennifer Macalady, professor of geosciences at Penn State and co-author on the paper. “It suggests that the evolution of complex life may be less about luck and more about the interplay between life and its environment, opening up exciting new avenues of research in our quest to understand our origins and our place in the universe.”
In contrast with the traditional view, researchers suggest that life formed when it was able to because of the global environment. It might be a relatively predictable process that happens as the planet goes on, the researchers suggest.
“We're arguing that intelligent life may not require a series of lucky breaks to exist,” said Mills, who worked in Professor Macalady’s astrobiology lab at Penn State, in a statement. “Humans didn't evolve ‘early’ or ‘late’ in Earth’s history, but ‘on time,’ when the conditions were in place. Perhaps it’s only a matter of time, and maybe other planets are able to achieve these conditions more rapidly than Earth did, while other planets might take even longer.”
The researchers behind the new study propose a number of ways to test their belief. That includes looking for other planets and understanding whether those supposed hard steps are unique to our planet, for instance – or even looking at our own planet, to see whether they might have happened more than once here.
The work is described in a paper, ‘A reassessment of the “hard-steps” model for the evolution of intelligent life’, published in the journal Science Advances.
