Why NASA is getting serious about UFOs

NASA's new chief is setting up an effort to further study unidentified flying objects within his first month in office.

Bill Nelson, the former Florida senator and spaceflight veteran, told CNN Business' Rachel Crane during a wide-ranging interview on Thursday that it's not clear to anyone — even in the upper echelons of the US space agency — what the high-speed objects observed by Navy pilots are. Nelson added that he does not believe the UFOs are evidence of extraterrestrials visiting Earth. "I think I would know" if that were the case, Nelson said. But, he acknowledged, it'd be premature to rule that out as a possibility.

Nelson's comments echo the findings of a new Pentagon report expected to be released later this month. Five sources familiar with the results of that study told CNN that US intelligence officials found no evidence that the UFOs are alien spacecraft, but investigators also have not reached a definitive assessment as to what these mysterious objects might be.

"We don't know if it's extraterrestrial. We don't know if it's an enemy. We don't know if it's an optical phenomenon," Nelson said. "We don't think [it's an optical phenomenon] because of the characteristics that those Navy jet pilots described ... And so the bottom line is, we want to know."