The U.S. Congress will host a public hearing on UFOs, now officially known as unexplained aerial phenomena, or UAP, for the first time in nearly half a century on Tuesday.

The hearing will focus on the contents of a Pentagon report from June 2021 that stated naval pilots had reported 144 encounters of unexplained aerial phenomena (UAPs) since 2004, the majority of which the department decided "probably do represent physical objects."

All those reports of strange flying things over the years, according to the Pentagon UFO report, fall into various categories, require further investigation, and remain mainly unexplained and unidentified.

According to the document, each UAP report "probably ... fall into one of five potential explanatory categories: airborne clutter, natural atmospheric phenomena, USG or US industry developmental programs, foreign adversary systems, and a catchall 'other' bin."

A couple of these categories prompt the report's authors to raise potential concerns:

"Safety concerns primarily center on aviators contending with an increasingly cluttered air domain. UAP would also represent a national security challenge if they are foreign adversary collection platforms or provide evidence a potential adversary has developed either a breakthrough or disruptive technology."

The UAP Task Force of the Department of Defense recorded 11 "documented instances in which pilots reported near misses with a UAP."

According to the assessment, there is insufficient information to determine whether any UAP belongs to a potential opponent.

Some of these purportedly propulsionless UFOs appear to be traveling at supersonic speeds in released video clips, while one piece of evidence (taken by the US Navy) appears to show a spherical UFO floating in midair while bouncing from side to side before plummeting into the water.

Luis Elizondo, a retired Pentagon official, told the Washington Post that UAPs have harmed secret U.S. nuclear weapons installations, forcing some to go offline.

The study does not answer the long-standing topic of whether we have been visited by aliens, but it does not reference E.T. in any way, either.

At the public hearing, which begins at 9 a.m. and will be streamed live here, EDT (1300 GMT) - U.S. representatives will question Undersecretary of Defense for Intelligence and Security Ronald Moultrie and Deputy Director of Naval Intelligence Scott Bray on the inexplicable phenomenon.

Following this public session, Congress will hold a secret, classified hearing on the activities of the Pentagon group tasked with investigating the sightings, known as the Airborne Object Identification and Management Synchronization Group (AOIMSG).