Long-anticipated 'UFO report' finally released. No, it's not aliens.

A government employee photographed a UFO that hovered for 15 minutes near Holloman Air Development Center in New Mexico, on Dec.16, 1957.

(Image credit: Bettmann/Getty Images)

The Pentagon has released a highly anticipated "UFO report" that in no way suggests aliens are responsible for more than 140 sightings of unidentified aerial phenomena (UAPs) by navy pilots.

Even so, the report indicates that "most of the UAP reported probably do represent physical objects." And out of the 144 UAP reports between 2004 and 2021, only one could be identified with "high confidence," according to the report; that one turned out to be a large, deflating balloon.

The report is the result of the Intelligence Authorization Act for the Fiscal Year 2021, in which the U.S. Senate Intelligence Committee called for an investigation into unidentified aerial phenomena (UAPs). And on Dec. 21, 2020, when the bill was enacted, the director of national intelligence and secretary of defense were given 180 days to produce a report for the committee. The six-month deadline expired this month.

Though the UAP sightings examined varied quite a bit, the report authors said, they found some patterns around the size, shape and in particular the propulsion of the UAPs. In 18 sightings, "observers reported unusual UAP movement patterns or flight characteristics," the report said. For instance, some of the UAP seemed to "remain stationary in winds aloft, move against the wind, maneuver abruptly or move at considerable speed, without discernible means of propulsion."

To get a handle on the diverse incidents, the report authors came up with five potential UAP categories: airborne clutter, such as birds, balloons and recreational drones; natural atmospheric phenomena, such as ice crystals that might create infrared or radar signals; classified U.S. government programs; foreign adversary systems (technology released by governments such as China or Russia, or some non-government entity); and a catchall "other" bin.

The report authors also give an overview of how to develop processes and training for U.S. military on what to do when they encounter a UAP so that the intelligence community can understand the potential threat. In fact, Florida Sen. Marco Rubio, who pushed for an investigation into the UAPs, said on CBS's 60 Minutes in May, "Anything that enters an airspace that's not supposed to be there is a threat," Rubio said. "I want us to take it seriously and have a process to take it seriously. I want us to have a process to analyze the data every time it comes in."

After the release of the UFO report Friday, Rubio, who is the acting chair of the Senate Select Committee on Intelligence, said in a statement: "For years, the men and women we trust to defend our country reported encounters with unidentified aircraft that had superior capabilities, and for years their concerns were often ignored and ridiculed," Rubio said, adding that the report is the first step in cataloging such incidents, though the Pentagon and intelligence community have a lot of work ahead to actually identify the threats.

Jeanna Bryner is managing editor of Scientific American. Previously she was editor in chief of Live Science and, prior to that, an editor at Scholastic's Science World magazine. Bryner has an English degree from Salisbury University, a master's degree in biogeochemistry and environmental sciences from the University of Maryland and a graduate science journalism degree from New York University. She has worked as a biologist in Florida, where she monitored wetlands and did field surveys for endangered species, including the gorgeous Florida Scrub Jay. She also received an ocean sciences journalism fellowship from the Woods Hole Oceanographic Institution. She is a firm believer that science is for everyone and that just about everything can be viewed through the lens of science.