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