Intelligent life may be planetary rule, not an random exception: new study
Intelligent life may develop on planets as a rule, not an exception — increasing the odds of humanity existing beyond Earth, according to a new study.
Researchers from Penn State University proposed in a new academic paper that human-like lifeforms could arise as a logical consequence of a planet’s development — contradicting the long-held “hard steps” theory.
“This new perspective suggests that the emergence of intelligent life might not be such a long shot after all,” said the scientific paper’s co-author Jason Wright, professor of astronomy and astrophysics at Penn State.
“Instead of a series of improbable events, evolution may be more of a predictable process, unfolding as global conditions allow,” he said. “Our framework applies not only to Earth, but also other planets, increasing the possibility that life similar to ours could exist elsewhere.”
The proposals of the paper, published in the peer-reviewed journal Science Advances Friday, stand at odds with the commonly held understanding of the evolution of complex life developed by theoretical physicist Brandon Carter in 1983 — the “hard steps” model.
That theory maintains that the development of complex, intelligent life was a highly unlikely event and a result of a series of rare occurrences — meaning that few, if any, civilizations are bound to exist on other planets.
But the new model, developed by the team of researchers, including astrophysicists and geobiologists, suggests that the development of humanity on Earth wasn’t so improbable after all.
“We are arguing that intelligent life may not require a series of lucky breaks to exist,” said Dan Mills, the paper’s lead author.
“Humans didn’t evolve ‘early’ or ‘late’ in Earth’s history, but ‘on time,’ when the conditions were in place,” he said. “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 study claims that key evolutionary steps were the result of logical and predictable events.
For instance, photosynthesis from plant life naturally created an oxygen-rich atmosphere which allowed for the expansion of animal life on the planet.
As opposed to Carter’s claims that complex life derived as an anomaly due to random favorable conditions — the new research suggests that “windows of habitability” are a natural progression in the life of the Earth itself — a rule which could apply to other planets as well.
Carter made his judgements based on the Sun’s lifespan — which contemporary researchers are now rejecting.
“We’re taking the view that rather than base our predictions on the lifespan of the Sun, we should use a geological time scale, because that’s how long it takes for the atmosphere and landscape to change,” Wright said.
“These are normal timescales on the Earth,” he said. “If life evolves with the planet, then it will evolve on a planetary time scale at a planetary pace.”
