Answers about whether people are alone in the universe might lie beneath Earth's surface.
The subsurface of Earth is very similar to that of the planet Mars, said IU geology professor Lisa Pratt. Pratt leads a team of scientists from the Indiana Princeton Tennessee Astrobiology Initiative, which is funded by the NASA Astrobiology Institute.
Pratt and her team recently found bacteria living in the subsurface of Earth. The key to life in the subsurface seems to be sulfur, which also exists on Mars. Pratt said that if it's possible for the bacteria to live here, there is a possibility that a similar organism could survive on Mars.
"It's very philosophical," Pratt said. "We're finding out we're not alone, where life originated and how it is evolving all over the universe."
Because the subsurfaces of Earth and Mars are so similar in their geographic and chemical makeups, the probability of microorganisms living on Mars is high, Pratt said.
"We should actually prove that (life) is not there," she said.