US government says it doesn't know what was behind 143 UFO sightings

But it's not ruling out aliens.

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The Office of the Director of National Intelligence (ODNI) has published its long-awaited report on nearly two decades worth of UFO sightings. And for the most part, it leaves more questions open than it answers. ODNI examined 144 reports of what it calls "unidentified aerial phenomenon" or UAP dating back to 2004.

Of those, 18 incidents may have involved advanced technology that the US can't explain. "Some UAP appeared to remain stationary in winds aloft, move against the wind, maneuver abruptly, or move at considerable speed, without discernable means of propulsion," the report states. ODNI says there's no evidence that any of the cases involve secret technology developed by the likes of Russia and China or an extraterrestrial entity, but it also didn't rule out those explanations.

"Of the 144 reports we are dealing with here, we have no clear indications that there is any non-terrestrial explanation for them — but we will go wherever the data takes us," a senior official for the government told CNN.

Outside of a single report where intelligence officials were able to determine the cause of the incident, there was too little data for ODNI to conclude what happened in the majority of the reports it examined. What it did say is that there's no one possible explanation for all the incidents it examined. The agency's investigators tried to put the reports into five categories: airborne clutter (like errant balloons), naturally occurring phenomenon, classified technology developed by the US government, secret technology developed by an adversary like China or Russia and a final and alluring catchall "other" category. However, ODNI is convinced the majority of the sightings involved "physical objects."

The report concludes with ODNI stating that understanding these incidents will require a consolidated and standardized approach across various government agencies. It also wants to invest in technologies like machine learning algorithms to examine the reports. Government officials will provide Congress with an update on its data collection efforts in 90 days, with periodic updates to follow after that.