"You have indicated that Mars was totally different thousands of years ago. Is it possible that there was a civilization on Mars thousands of years ago?" Rohrabacher asked.
The response was pretty clear.
"Mars was different billions of years ago, not thousands of years ago. And there's no evidence that I'm aware of that ..." a professor of geochemistry replied.
"Would you rule that out, that — see there's some people — well, anyway," Rohrabacher said.
"I would say that is extremely unlikely," the scientist said.
NASA has yet to find evidence of life on Mars. And while all hope isn't lost, the agency says any life on the red planet would probably be microscopic.
Rohrabacher's talk of Martians got the most media attention. But he also offered some other concerns about a manned mission to Mars.
"I think the moon is close by. And whatever we can actually get benefit out of going back there, we should before you take the next step," Rohrabacher said.
It's been 45 years since a human walked on the moon, and NASA notes it still has a lot of unanswered questions about it. As for Mars, the agency wants to put astronauts on the red planet by 2030.