WASHINGTON — Pentagon officials testifying at a House subcommittee hearing on Tuesday showed a previously classified video of an unidentified aerial phenomenon, a fleeting color image of a reflective spherical object speeding past a military fighter jet.
The congressional hearing was the first in more than a half-century to focus on military reports of unexplained phenomena — the current term for U.F.O.s — and a chance for lawmakers to prod the Pentagon for more information. It was also an opportunity for government officials to clarify why explanations were not forthcoming and outline their plans for improving data collection.
The Pentagon officials testified under oath that the government had not collected materials from any alien landing on Earth, pushing back on at least one favored conspiracy theory.
The highlight of the hearing was a split-second image, shot last year through the window of an FA-18 fighter jet, of a spherical object in the distance. The pilot also reported observing an object. It remains unexplained and is an example of how difficult it is to determine what a short video clip may show.
Pentagon officials also played a video and displayed an image shot through night-vision lenses that showed glowing green triangles moving through the air. The first video, shot on the West Coast in 2019, puzzled military officials. But the small triangles in the second recording, made this year on the East Coast, were determined to be drones, the spooky look being an artifact of the lens used to produce the imagery.
“This time, other U.S. Navy assets also observed unmanned aerial systems nearby, and we’re now reasonably confident that these triangles correlate to unmanned aerial systems in the air,” said Scott W. Bray, the deputy director of naval intelligence.
The declassified videos were released at the urging of lawmakers as they pledged to bring transparency to an investigation of unexplained reports by miliary pilots and others that have long been shrouded in stigma, confusion and secrecy.
The hearing was followed by a classified session, where the Pentagon officials could candidly discuss the capabilities and limitations of the cameras and other sensors used to record images.
In the open session, Pentagon officials said they had to be careful.
“We do not want potential adversaries to know exactly what we’re able to see or understand, or how we come to the conclusion,” Mr. Bray said. “Therefore, disclosures must be carefully considered on a case-by-case basis.”
The Pentagon is creating a new task force to examine the reports, with the aim of collecting more information about incidents so that they can be better, and more quickly, identified.
Part of the effort going forward, said Ronald S. Moultrie, the Defense Department’s under secretary for intelligence, is to make sure that military sensors are properly calibrated to record as much information as practical on the unexplained phenomena. Better, higher-fidelity data will allow the Pentagon to draw better conclusions about unidentified phenomena.
Mr. Bray said the Pentagon was focused on a few reports of unexplained phenomena with strange flight characteristics — like fast movement or no visible means of propulsion. “We’ll go wherever the data takes us,” Mr. Bray said. “Again, we’ve made no assumptions about what this is or isn’t.”
The Office of the Director of National Intelligence released a report last year, largely compiled by the military, cataloging unexplained aerial phenomena dating to 2004. The intelligence community criticized the document because it failed to draw conclusions or offer explanations for most of the events.
On Tuesday, Mr. Bray tried to explain why it is so difficult to identify the images in the fuzzy videos. But lawmakers insisted that the Pentagon had been too dismissive of explanations.
“You need to show us, Congress and the American public, whose imagination you have captured, you are willing to follow the facts where they lead,” said Representative André Carson, Democrat of Indiana and the chairman of the House Intelligence subcommittee that held the hearing.
“We fear sometimes that D.O.D. is focused more on emphasizing what it can explain, not investigating what it can’t,” he said. “I am looking for you to assure us today that all conclusions are on the table.”
Mr. Moultrie, who under questioning from lawmakers said he was a fan of science fiction and attended at least one sci-fi convention, tried to assure Congress that the Pentagon was taking the reports seriously.
“We have our inquisitiveness; we have our questions,” he said. “We want to know what’s out there as much as you want to know what’s out there.”
Privately, many senior U.S. officials have been dismissive of theories suggesting that unknown objects captured in videos could be aliens and insist there is no evidence that such explanations are probable.
Mr. Bray tried to stamp out speculation that the phenomena were extraterrestrial in origin. “We have no material. We have detected no emanations within the U.A.P. task force that would suggest it’s anything nonterrestrial in origin,” he said, referring to unidentified aerial phenomena.
Representative Rick Crawford, Republican of Arkansas, said he was more interested in discussions of Russian or Chinese hypersonic weapons programs than unidentified phenomena. But he said it was important to identify the images.
The government’s inability to identify objects in sensitive operating areas was “tantamount to an intelligence failure that we certainly want to avoid,” Mr. Crawford said. “It’s not about finding alien spacecraft.”
Officials are also skeptical that the phenomena could be some unknown Chinese or Russian technology, but concede it would be a significant concern if they were. That possibility, lawmakers and officials have said, is why the phenomena need to be examined more carefully.
“When we spot something we don’t understand or can’t identify in our airspace, it’s the job of those we entrust with our national security to investigate and report back,” Representative Adam B. Schiff, the California Democrat who leads the Intelligence Committee, said on Tuesday.
Congress last held a public hearing on the issue decades ago, after Project Blue Book, the Air Force’s flawed effort to investigate reports of alien sightings, which inspired generations of television programs.
After the report last year, intelligence officials pledged to renew their efforts. Prompted by Congress, the Pentagon overhauled its task force for looking into the unexplained events, calling it the Airborne Object Identification and Management Synchronization Group.
In his opening remarks, Mr. Carson criticized the Pentagon for failing to name a director to lead the new task force and pledged to bring “the organization out of the shadows.”
Military officers who were too embarrassed to report unexplained phenomena had impeded “good intelligence analysis,” Mr. Carson said.
“Pilots avoided reporting or were laughed at when they did,” he said.
Representative Tim Burchett, Republican of Tennessee, is not a member of the Intelligence Committee but sat in on the hearing. He said that the Pentagon was not transparent about its findings and that officials were too dismissive of theories that the videos could show objects coming from space or alien craft.
“We just got hosed. On some level I think it is a cover-up,” he said. “I have a T-shirt I sell on my website. It says, ‘More people believe in U.F.O.s than believe in Congress.’”
But outside experts who specialize in debunking conspiracy theories said the testimony was important. Mick West, a science writer who has focused on debunking conspiracy theories, has long argued that the objects seen in the videos recorded by the military have plausible — and dry — explanations that are far more likely than any kind of extraworldly technology.
After the hearing, Mr. West said the testimony confirmed his theory that the triangle images were created by the camera lens.
He also said the spherical object in the color video was almost certainly a balloon.