Thomas Zurbuchen, the associate administrator for NASA's Science Mission directorate, says it's likely that there's life beyond Earth.
"Is there life beyond Earth? I think the answer is yes — but we just don’t know," Zurbuchen said during an interview at Boston University. "The simple reason I think so is because we underestimated nature when we doubted whether water or complex molecules would exist beyond Earth. Each one of those is much easier to achieve than we thought possible."
It's common logic: space is so incomprehensibly vast that somewhere out there, the right conditions for life must exist.
But the fact remains that earthlike conditions in outer space don't guarantee life, and University College London biochemist Nick Lane has argued that we don't have any sort of statistical justification for that assumption — arguments like Zurbuchen's are extrapolations from the singular data point of life on Earth.
Pale Blue Dot
But whether Zurbuchen's hunch is right or wrong, he argues that it won't make a bit of difference if we don't first make sure that Earth can continue to sustain life.
"No matter what the answer to that question is," Zurbechen replied to a question about off-world settlements, "we have to keep Earth livable. It’s unsafe to do otherwise. I do think about terraforming other planets a small percentage of the time, but much more time I spend focused on ways to keep the Earth livable and wonderful — not the other way around."
If we don't address the ongoing damage caused by global climate change, Zurbuchen seems to be implying, any space-exploring extraterrestrials won't find anything more than the remains of our society.
Read More: If Traveling to Space Was as Easy as Traveling to Paris [Boston University Newsroom]
More on extraterrestrial life: The Search for Aliens May Depend on In-Space Assembly