Scientists could be on the cusp of detecting life beyond Earth, but only if they have the tools and the knowledge to recognize it, an expert panel has concluded.
In a report to the U.S. National Academy of Sciences published Wednesday, the panel attempts to lay out a road map for accelerating the search for extraterrestrial life by identifying key questions and technical challenges that will come into play when researchers are faced with ambiguous signs of an alien biology – a possibility that may be fast approaching based on recent developments in astronomy and planetary exploration.
“We’re in a time when, in the next 10 to 20 years, the potential for discovery is huge,” said Barbara Sherwood Lollar, the University of Toronto geologist who led the international panel.
The catch is that recent findings have only expanded and complicated scientists’ understanding of what ingredients and locations in our solar system and others might make it possible for life to emerge. That requires taking a broad view, Dr. Sherwood Lollar said, in order to encompass the possibility of discovering life in a form that is entirely unanticipated.
“Life need not be as we know it,” she said.
Among the report’s recommendations are investments in technologies that can be used to identify a wide range of molecular markers that can indicate the presence of life in an alien environment, as well as a better understanding of non-living processes that could mimic those signs.
The markers – also known as “biosignatures” – could be hidden in a range of locations in our own solar system or could be detected remotely as astronomers improve their ability to measure the atmospheric compositions of planets discovered orbiting around other stars.
While the mystery of whether there is life beyond our own planet has intrigued people for centuries, a string of recent discoveries suggests that the current generation of scientists working in the field is poised to make significant progress on the question.
The discoveries include evidence published in July indicating a layer of liquid water underneath a Martian glacier, and a report last week of the possible first detection of an “exomoon” – a moon orbiting a planet in another solar system. The former identifies a new environment where the search for life might be directed on Mars, while the latter suggests that there are many more small bodies in distant solar systems that have yet to be observed, multiplying the possible places where life could spring into being.
The report also stressed the need to consider that signs of life may be located deep below the surface of a planet. That suggests robotic drilling rigs will be needed to address the question in our own solar system, while on other worlds, astronomers may depend on gasses venting from the interior of a planet to understand what may be living there.
Dr. Sherwood Lollar said that this thinking is reinforced by findings that bacterial life on Earth can exist at much greater depths than once thought, feasting on chemical energy derived from rocks, rather than from sunlight.
In general, the report concerns itself with the search for life signs that are most likely to be related to microscopic organisms, not complex animal life or intelligent civilizations – a far less likely proposition.
The report was released during a public briefing in Washington on Wednesday. It is intended to help guide the U.S. space program and science funding agencies, but the recommendations are relevant to researchers working in the field outside of the United States, including in Canada.
Ralph Pudritz, an astronomer and founding director of McMaster University’s Origins Institute, which brings together researchers looking to understand the emergence of life, said the report underscores the need to tie such research to a detailed understanding of conditions on other words as well as the early Earth.
McMaster has recently opened a new laboratory where such conditions can be simulated in a controlled way.
“By doing these experiments, we can hope to help determine which environments might be successful in driving interesting pre-biotic chemistry, and to better understand what some of the chemical and molecular signatures are that might be produced,” Dr. Pudritz said.
But while Canada has scientists that are investigating the unknowns, it lacks a larger strategy for how to marshal funding and organize efforts nationally around such big interdisciplinary questions. And unlike the U.S. National Aeronautics and Space Administration (NASA), the Canadian counterpart does not possess a cadre of in-house scientists that can develop expertise in the area.
“Figuring out how to support long-term big science remains one of our national challenges,” Dr. Sherwood Lollar said.