(NewsNation) — UFOs and UAPs have become common acronyms in news headlines as members of Congress have called for more transparency on what the government knows — and doesn’t know — about unidentified aerial phenomena, previously the subjects of conspiracy theories and grainy images.

Members of Congress have led a bipartisan effort to investigate and declassify government documents containing information regarding such unidentified phenomena following the testimony of UFO whistleblower David Grusch, a former Air Force and intelligence officer, before a House Oversight subcommittee in July 2023.

Grusch testified the U.S. is concealing a longstanding program that retrieves and reverse engineers unidentified flying objects.

Grusch said he brought his concerns to the Office of the Inspector General of the Intelligence Community, including classified details he could not share with the public or Congress in an open setting.

Now, in early 2024, the House Oversight Committee will again get a classified briefing from the intelligence community inspector general.

As the ability to track, record and identify the objects becomes more sophisticated, an independent panel has urged NASA to improve the data it collects about unidentified aerial phenomena.

But what exactly do the acronyms “UFO” and “UAP” stand for, and why have they become such a hot topic of conversation?

What are UFOs?

“UFOs,” or “unidentified flying objects,” have captured the nation’s imagination since the late 1940s and have been the source of conspiracies and theories about extraterrestrial life outside Earth.

The UFO craze hit the United States in 1947. In June of that year, pilot Kenneth Arnold said he saw shiny, unidentifiable objects flying in the sky near Mt. Rainier in Washington. Several weeks later, military personnel announced they were in possession of a “flying disc” after a local rancher found strange debris on his land in Roswell, New Mexico.

Decades later, conspiracy theorists claimed that the Roswell disc was a UFO and that the government covered up the incident.

“I think there’s always this anticipation of, did something really happen in Roswell and are there really extraterrestrial beings,” said Juanita Jennings, public affairs specialist for Roswell.

The term “UFO” was added to the world’s lexicon by the U.S. Air Force in 1952, just five years after the Roswell sighting, USA Today reported.

Since then, UFOs have been affiliated with the belief there is extraterrestrial life or aliens outside Earth. People have called those flying objects all sorts of names, such as “flying saucers,” “hovering lights” and “floating discs,” according to HowStuffWorks.

However, it’s important to note that UFOs don’t necessarily mean aliens are visiting Earth, either, BBC reported. UFOs can also refer to other objects in the sky such as weather balloons or drones.

But the technology of some of these objects has been seen as too advanced for our modern day, with some saying the saucers can suddenly zip off or disappear into the night.

In an interview with NewsNation in July, Rep. Tim Burchett, R-Tenn., even said UFOs had the ability to fly underwater and not show a heat trail.

Interest in UFOs has become so widespread that NASA created its own team in 2022 to study the subject.

What are UAPs?

“UAP,” or “unidentified aerial phenomena,” is used to describe unexplainable sights in the sky, not just unidentified flying objects.

While still a fairly new term, it has become more popular among officials, studies and investigations when discussing sensitive information regarding potential UFO/UAP sightings.

The National Aeronautics and Space Administration coined the acronym to describe observations of the sky that can’t be identified as a known object or phenomenon, USA Today reported.

While both acronyms refer to the same unidentified events reported in the sky, government agencies began using UAPs instead of UFOs in 2021 in hopes of muting some of the conspiracies flooding the public.

The issue with using UFO is that most people correlate it with aliens or extraterrestrials. The goal of using the term UAPs is to eliminate the baggage the term UFO carries.

In 2021, the Office of the Director of National Intelligence (ODNI) used the term UAP in its Preliminary Assessment: Unidentified Aerial Phenomena report. The document did not use the term UFO once or mention anything about extraterrestrials, HowStuffWorks reported.

“Most of the UAP reported probably do represent physical objects given that a majority of UAP were registered across multiple sensors, to include radar, infrared, electro-optical, weapon seekers and visual observation,” the report said.

However, the report also reiterated that while it might be easy to dismiss eyewitness reports of physical objects, it’s a lot harder for agencies to deny eyewitnesses of UAPs corroborated on a radar, HowStuffWorks reported.

UAPs can also be classified into five categories, according to the report. Those categories include airborne clutter, natural atmospheric phenomena, USG or U.S. industry development programs, foreign adversary systems and “other,” USA Today reported.

Why have UFOs and UAPs become a hot topic of conversation?

Since making headlines, there has been a huge bipartisan push for the Pentagon to collect and declassify UFO/UAP data and documentation.

Congress has moved forward with its investigation into them after claims made by Grusch, a former member of the National Geospatial-Intelligence Agency.

Grusch spoke in 2023 to investigative journalist Ross Coulthart on NewsNation about his time in Congress’ Unidentified Aerial Phenomena task force, which is now called the All-domain Anomaly Resolution Office, or AARO.

Congress held a hearing in 2023 on threats posed by unidentified flying objects and unexplained aerial phenomena, marking its first hearing on UFOs in more than 50 years.

Lawmakers from both parties have claimed UFOs/UAPs are a national security concern.

Sightings of what appear to be aircraft flying without discernible means of propulsion have been reported near military bases and coastlines, raising the prospect that witnesses have spotted undiscovered or secret Chinese or Russian technology.

In early 2024, UFO journalist Jeremy Corbell released footage of what he calls a “jellyfish” UAP spotted in Iraq in 2018.

NewsNation has not independently verified the footage that, according to Corbell, shows an object that resembles a jellyfish as it moves through a sensitive military installation before moving over water and submerging.

As with the “jellyfish” UAP, most sightings are usually fleeting.

Some appear for no more than an instant on camera — and then sometimes end up distorted by the camera lens. The U.S. government is believed to hold additional technical information on the sightings that it has not disclosed publicly.

The Pentagon has said there is no information “to substantiate claims that any programs regarding the possession or reverse engineering of extraterrestrial materials have existed in the past or exist currently.”

However, Sen. Chuck Schumer, D-N.Y., introduced new legislation to declassify government records related to UFOs. Congress passed the legislation in a defense bill in 2023 that included a measure requiring the National Archives to release all documents related to UAPs to the public within 25 years.

A new bipartisan bill went further and encouraged commercial pilots to report sightings of UAPs and UFOs to the United States government.

The highly anticipated House Oversight subcommittee hearing on UAPs in 2023 brought out hundreds of people eager to hear from the three witnesses firsthand, and Rep. Glenn Grothman, R-Wis., made it clear he believes the House of Representatives investigation has just begun.

The All-domain Anomaly Resolution Office was tasked with creating a website by Congress. It will serve as a place for the AARO to release declassified UFO investigation results and a system for the general public to report sightings. 

Now, in early 2024, the House Oversight Committee will again get a classified briefing from the intelligence community inspector general.

The briefing will be limited to just committee members.

NewsNation special correspondent and investigative journalist Ross Coulthart fears the House Oversight Committee will only get general information.

“I think at best what they’re going to get is an explanation as to why the inspector general determined that Mr. Grusch’s allegations were credible and urgent,” Coulthart said. “I think that’s very important because a lot of people have said that there’s no basis to Mr. Grusch’s allegations. A lot of people have suggested that it’s all unsourced, whereas we know that the inspector general deposed witnesses. He actually got witnesses to come forward with evidence.”

The Associated Press, Taylor Delandro, Mystery Wire contributed to this report.