It's one of the most longstanding questions in biology: how did life first arise?
Research on the topic abounds, but there's no one accepted answer. And according to one new paper, the chances that life emerged by pure chance on Earth are so slim that it's possible that our planet was instead seeded by "advanced extraterrestrials."
While Imperial College London professor of systems biology Robert Endres concedes that the emergence of life still could've been the result of chemical reactions moving from highly disordered to ordered arrangements, as Universe Today reports, he's also leaving open to that much more exotic possibility.
The "aliens did it" hypothesis would "violate Occam's razor," Endres admitted in his yet-to-be-peer-reviewed paper, but he refuses to rule it out as a "speculative but logically open alternative."
Panspermia, you'll recall, is the theory that life spread throughout the universe via planetoids, asteroids, or other natural objects. Push the idea one step further, and you land on "directed panspermia": the hypothesis that an extraterrestrial civilization deliberately brought life to Earth.
The theory was first proposed in the early 1970s to explain the incredible unlikeliness of life on Earth. Even at the time, the authors — including molecular biologist Francis Crick, famous for discovering the helical structure of DNA, and Salk Institute for Biological Studies chemist Leslie Orgel — admitted that "scientific evidence" was "inadequate" to "say anything about the probability."
For his research, Endres developed a "framework based on information theory and algorithmic complexity" to estimate the "difficulty of assembling structured biological information under plausible prebiotic conditions."
He concluded that a "purely random soup," made up of molecules that eventually enabled the formation of life on Earth, was "too lossy," and that "some form of prebiotic informational structure must precede Darwinian evolution."
Endres also explored the "irresistible" question of whether our planet was terraformed by another species.
"Today, humans seriously contemplate terraforming Mars or Venus in scientific journals," the paper reads. "If advanced civilizations exist, it is not implausible they might attempt similar interventions — out of curiosity, necessity, or design."
Still, he admits that it's a long shot.
"Invoking terraforming adds explanatory complexity without constraint," Endres wrote. "And while we cannot prove that abiogenesis is inevitable, it remains consistent with thermodynamics," he added, referring to a hypothetical natural process by which life would arise from non-living matter.
More on life on Earth: Scientists Say They've Created a New Form of Life More Perfect Than the One Nature Made