NASA has held its first public meeting of a panel studying unidentified aerial phenomena, commonly known as “UFOs.” The 16-member panel said Wednesday more high-quality data is needed to explain many of the sightings, but that there’s no evidence any of them could be explained by extraterrestrial origins. Wednesday’s event at NASA headquarters in Washington, D.C., came after Congress last year held its first hearings on the subject in over half a century.