WASHINGTON — A new unclassified document on unidentified sightings, or U.F.O.s, reported to the U.S. military found that a majority have ordinary explanations, though dozens remain officially unexplained.
The failure to categorize many incidents has frustrated intelligence officials and fueled conspiracy theories, but Pentagon officials say the incomplete findings are a result of inadequate sensor collection, not evidence of advanced technology or any sort of government cover-up.
The new report, released by the Office of the Director of National Intelligence, examines 366 incidents either observed or submitted since the last report on unexplained phenomena was released in 2021.
With the release of any government report on U.F.O.s, officials hope the information will quell speculation around the unexplained incidents. But such hopes are inevitably dashed because incidents that cannot be categorized fuel new rounds of speculation and conspiracy.
Of the newly documented incidents, 26 were found to be drones, 163 were balloons, and six more were airborne clutter, such as birds or trash. The remaining 171 incidents have not yet been attributed.
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A portion of those unexplained incidents that “demonstrate unusual flight characteristics” will get further study, according to the report. But the report does not outline how many incidents fall under that category, an omission likely to stoke further speculation by people who have embraced explanations such as otherworldly visitors or advanced unknown technology by adversarial powers.
Mick West, a science writer who has focused on debunking conspiracy theories, said the government should put out specific information about how many cases it is continuing to examine.
“If they had a case that had enough information to determine something was genuinely doing unusual things, that would be a huge deal,” Mr. West said. “But what they are basically saying is they don’t have cases where it is unambiguously something interesting.”
Military and intelligence officials have said in many cases that imperfect sensor readings have prevented any sort of formal conclusion. Even in those cases, however, the limited available evidence suggests that the incidents are likely to have more ordinary explanations as well.
On Thursday, Brig. Gen. Patrick S. Ryder, the Pentagon spokesman, said the Defense Department had established improved reporting procedures to collect more information.
“More data allows us to be a little bit more rigorous in how we go after investigating these incidents,” General Ryder said.
The report also noted that there were no adverse health effects linked to the unexplained sightings. The finding, analysts said, was important because some people had tried to tie unexplained incidents to Havana syndrome, the mysterious ailments that have affected spies and diplomats.
As with the previous report, the new document made no direct mention of extraterrestrials or aliens. But in other public comments, Pentagon officials have said there is no evidence of space aliens, and that they have not collected extraterrestrial material or anything else that smacks of the stuff of science fiction or “The X-Files.”
At a Defense Department briefing with members of the media in December, this reporter asked Ronald Moultrie, the Pentagon’s top intelligence official, if the government had collected “affirmative evidence” that any of the unexplained anomalies was “a space alien.”
“At this time, the answer’s no, we have nothing,” he said, adding that they had not seen anything “that would lead us to believe that any of the objects that we have seen are of alien origin, if you will.”
Sean Kirkpatrick, the head of the Pentagon task force examining the unexplained incidents, said officials are setting up mechanisms to make sure that no American government testing of classified programs — like futuristic and secret stealth aircraft or drones — is the cause of the mysterious reports.
Congress has pressed the Pentagon and intelligence agencies to do a new review of material they have collected, stretching back to the days of the Air Force’s Project Blue Book.
In that era, the Pentagon referred to reports — sometimes of their own classified programs — as unidentified flying objects. In recent years, as new reports from Navy pilots sparked new interest, the Pentagon began calling the unidentified sightings unidentified aerial phenomena, reflecting a belief that some incidents might not be objects but optical illusions or poorly understood, but natural, atmospheric events.
With the creation of yet another task force to examine the sightings, the Pentagon changed the name again to “unidentified anomalous phenomena,” keeping the same acronym but reflecting that some unexplained incidents could be on the water, under the sea or in space.
The report released Thursday was the unclassified version of a secret report that was due to go to Congress in late October, but was submitted on Wednesday, several months late.
While some in the public have wondered why the unclassified report took so long to release, officials insist it is bureaucratic inertia, not a secret cover-up of alien visitation, that accounts for the delay.