How can extraterrestrial life be identified if it looks nothing like organisms on earth?
The U.S. National Aeronautics and Space Administration has funded a project to find an answer to that question. And Allison Enright, an assistant professor of environmental geochemistry at the University of New Brunswick, has been part of the team helping to do that.
"Examples of that would be things like looking for DNA," Enright said. "We don't know that DNA would evolve the same way on another planet. So rather than look chemically for the structure of DNA or something similar, we might look for energetic bio signatures."
"Or we might look for evidence of the existence of cells, but not based on the chemistry or the structure that we would expect to observe on earth."
Enright spent the summer as a visiting scholar at Harvard University working on the project, which falls within the Interdisciplinary Consortium for Astrobiology Research (ICAR). ICAR supports NASA's astrobiology program, which examines the distribution, evolution and origins of life in the universe.
She worked with a small team of researchers studying electrochemistry at Harvard. But a professor at Georgetown University is leading the five-year project, which also includes work from 50 to 100 scientists at other universities.
Despite the potentially far-reaching aim of the project, its work will also be useful on this planet.
"Just because this particular project is really exciting, and we're thinking about life outside of Earth, it's not just an investment in an idea that doesn't benefit people," Enright said.
She said her work can help with wastewater management or environmental monitoring on this planet.
The large five year project should be wrapping up in the coming months, she said. But timelines were delayed by the pandemic and as she's not the project leader, Enright couldn't say for certain when it will end.
All life has energy
One thing that unites every living thing on earth is the "process of having to take in energy from the environment, and then harness it to fulfill some kind of purpose or function and then release waste products," Enright said.
She said this is likely the case for organisms on other planets as well.
"What would be a life process if there was no conversion of energy? Life is energy."
So the team looked to detect evidence of biological energy transfers that take place through electron and ion interactions. The energy transfer can be used as a biosignature – meaning evidence of past or present life.
The team also experimented with conditions that might be found on other planets. They were able to identify patterns in how bacteria organize under specific chemical conditions, conditions that humans could seek out on other planets.
"So by looking at environments that we could find with the technology and instruments we have, and then knowing what evidence to look for once we get there," Enright said. "We're sort of narrowing down into what would be a proof positive or a good life detection."
The thrill of working on a project for NASA
Enright said that a project of this size fosters a powerful and collaborative atmosphere for scientists.
'When you have projects that are of this magnitude…and you have lots of different contributors with different expertise, it creates an environment where you can be more innovative just because you have so many people with this similar shared goal," she said.
She said that the chance to work on something like this is a full-circle moment for many scientists.
"I think a lot of us end up becoming scientists, because we're interested in science fiction, maybe as children or earlier in our career. And coming even into labs and onto research teams where we get to sort of explore these ideas can be really exciting."