Stephen Dowling
Deputy editor, BBC Future

Today's hearing has ended, with some of the witnesses saying they don't believe their experiences can be understood through routine explanations.

But not all "alien" signals come from space.

Astronomers spend a lot of their time looking up, scanning the heavens for signals that can give them clues about distant stars, exoplanets and galaxies. But sometimes, they also need to lower their heads and look closer to home.

In 1998, scientists in Australia's Parke's Observatory in New South Wales discovered strange radio bursts just a few milliseconds long, which were detected over several weeks. Strangely, they only seemed to occur during office hours at around the same time each day.

Then in 2015, scientists managed to trace the source. The culprit was the observatory's microwave, external. The bursts were recorded during periods when researchers were heating up their food. Opening the microwave oven before it had pinged led to brief emissions of radio waves of around 2.4GHz that were picked up by the observatory's sensitive antenna.

You can read more on investigations into UFOs in our story on "alien" signals and how they are attracting serious scientific scrutiny.

Thank you for joining us.

We're moving away from text coverage of this ongoing hearing, but you can keep watching live at the top of this page.

Though Nasa says that most UAP sightings such as the ones we've heard about from today's witnesses are likely not extraterrestrial, external in origin, you can check out more about what we do know about alien life here:

Lunar bugs to ocean moon: Seven things science has revealed about aliens so far

Where we might find aliens in the next decade

Thank you for joining us.

Richard Gray
Editor, BBC Future

We're hearing from witnesses of UAP events at this hearing today. But even many people who have never seen unexplained phenomena themselves believe them to be caused by extraterrestrial life.

Conspiracy theories are not new – they pop up (and were believed) throughout human history, external.

After a fire destroyed ancient Rome in 64AD, for example, Emperor Nero was blamed. The story spread as fast as the flames, but historians now believe it was unlikely.

There are many reasons why conspiracy theories take hold and capture people's imaginations. Researchers studying conspiracy theories have uncovered what my colleague Melissa Hogenboom describes as a "smorgasbord of explanations":

• People drawn to conspiracy theories tend to want to feel unique, external. The "secret" information they claim to have access to can help them feel this.
• Those who believe in conspiracy theories often feel more politically disengaged., external
• Conspiracy theories can also help people make sense of the world they feel is out of control, external as the answers they offer can be psychologically comforting, external.
• But ideas of a coverup or global conspiracies can also leave people feeling even more uncertain and powerless, external.
• Sightings of UFOs (or UAPs as they are now known) tend to spike during periods of macroeconomic strife, external. There was a notable surge during the Covid-19 pandemic, for example.
• If politicians acknowledge the idea that visits by aliens might be being kept secret, then the wider public are more likely to see conspiracy theories in a favourable way, external.

To find out more about why people believe conspiracies, read this article by Melissa Hogenboom on BBC Future.

Congressman Nick Begich, a Republican from Alaska, asks Knapp about "the long game" of this topic, given the easy access the general public has to videos.

Knapp tells the committee that the "secret is out" given the large number of videos that are out there and available to the public.

"The public senses that it's real and the people in authority dismiss them," he says.

Knapp adds that there is a sense from those in authority that the public can't handle the truth, but he says they can.

Witness Wiggins tells the committee there should be better systems in place for active duty military members to report UAP incidences like the one he experienced without the fear of professional reprisals.

"I have been in the Navy for almost 24 years, but what about the sailors who have been there for two years that experience things like this?" he asks, explaining that those newer service members might not know what to do, or might be fearful to make such a report so early on in their careers.

Burlison thanks Wiggins for being the first witness to come forward about a UAP sighting while still serving in the military.

Congressman Eric Burlison, a Missouri Republican, is asking questions of Knapp now.

He asks about a clip that shows a "missile being launched at orb" in Yemen. Knapp tells him that he's heard of the incident but hadn't himself seen the video.

Knapp says there is a whole bank of UAP videos that exists but that Congress hasn't seen.

"That's a hellfire missile smacking into that UFO, and bouncing right off - and it kept going," he says.

Burlison says he doesn't what to speculate about what the video shows, but says he wonders why Congress is being kept from information that could explain the video.

Republican committee member Representative Lauren Boebert has just asked witness Alexandro Wiggins whether he thinks his experience with the self-luminous tic-tac aboard the USS Jackson a few years ago could be explained by routine matters?

"It cannot," he replies, adding that he has never been debriefed by any government agency on what he witnessed following his reporting of the experience.

"I've not had any discussion outside of that day - there's been no communication to me or requests from me," he tells the hearing.

Boebert then asks Nucetelli if authorities ever got in touch about his sightings of "red squares". He says an from Aaro (All-domain Anomaly Resolution Office) followed up, but no one from the US Air Force did.

Now that opening statements have concluded, we're hearing the first questions from members of Congress.

Luna, the chair of the committee, asks Borland about the large triangular object he just told the committe about and how he can be sure of what he saw.

Borland details his experience, including that he saw the object stop 100ft (30m) above him and noticed that his phone froze.

He says he could never see the top of the craft, which was painted a black metallic colour. He also notes that there was a gold "plasma" going around the top of the object.

Borland describes feeling static around his body and the smell of a thunderstorm.

Image source, US House of Representatives

Dylan Borland, a UAP witness and US Air Force veteran, says he has endured "sustained reprisals" because of his whistleblowing around these sightings.

In 2012, he says he saw an "approximately 100ft equilateral triangle take off" from the base where he was working, at around 01:30 in the morning.

Borland says the object appeared to be made up of a "fluid or dynamic" material.

Image source, US House of Representatives

Alexandro Wiggins - who is a Navy member speaking in his personal capacity - tells the of an incident he saw on 15 February 2023 while aboard the USS Jackson Navy ship off the coast of southern California.

"I'm here to provide a first-hand account of what I saw," Wiggins says, adding that he witnessed flying objects "not consistent with conventional aircraft or drones".

He says he saw a "self-luminous tic-tac-shaped object emerge from the ocean before linking up with three other similar objects". All four of them then sped up and disappeared he said, and he couldn't figure out how they were propelling themselves and they quickly disappeared from radar.

Wiggins says that he wants his observations investigated by specialists because of the potential safety issues that come from these UAPs, no matter their origins.

Declassification and transparency, where possible, are "essential", he says.

Former US Air Force veteran Jeffrey Nuccetelli says he is speaking to the committee today because citizens have the right to know the truth - a truth that "remains hidden", silenced by "stigma and confusion".

He says five UAP events occurred in Vandenberg, California between 2003 and 2005, explaining that each was witnessed by multiple personnel.

Nuccetelli says they began on 3 October, 2003, when Boeing contractors reported a "massive glowing red square silently hovering" above two missile defence sites.

The event is now known as the "Vandenberg glowing red square event", he adds.

He also says that while he was on duty that night, security guards reported the sighting, with friends of his screaming: "It's coming right at us! It's coming right for us! and "Now it's here!"

As a reminder, UAP stands for unidentified anomalous phenomena, which might describe unexplainable sightings in the sea, air or space. In the air, these sightings are also called UFOs, or unidentified flying objects, and often refer to alien spacecraft.

Image source, Congressional Oversight Committee

We're hearing now from Texas Congresswoman Jasmine Crockett, the Democratic ranking member on the committee.

She says Nasa has said the origins of UAP sightings and other mysteries are likely not extra-terrestrial,, external but instead may be explained by new technologies developed by US global adversaries.

Regardless, the US government has a responsibility to investigate what's happening and disclose what they find, Crockett says.

The chairwoman of this committee, Republican Representative Anna Paulina Luna, says bringing this information about UAPs to the public is important work.

She says that the hearing today is not an effort to fuel speculation, but to ask the questions that every American has the right to ask.

She says committee members want to hear about "what we do know, what we don't know and why in a free society are we being told so little."

The UAP hearing begins with Republican Congresswoman Anna Paulina Luna saying the American public deserves to know the truth.

"We cannot maintain trust in government if we keep American people in the dark," she says.

We'll bring you all the top lines on this page - stay tuned, and watch live at the top of the page.

The hearing has now begun - you can follow along by clicking Watch live at the top of this page.

You'll be hearing witnesses talking about UAPs rather than UFOs today.

UAP stands for unidentified anomalous phenomena, used to describe unexplainable sights in the air, sea or space.

UFO stands for unidentified flying object, often used to describe alien spacecraft.

Both acronyms essentially refer to the same thing: an object that can’t be identified.

But as a US Navy spokesman explained a couple years ago, UAP sounds less, well, crazy. Calling them "UFOs" might discourage pilots from reporting unexplained sightings for fear of being stigmatised.

Government officials and lawmakers have been favouring UAP over UFO. (But yes, we're talking about UFOs.)

Four witnesses will be attending the hearing today.

Jeffrey Nuccetelli - a US Air Force veteran. On social media, he said he is a UAP witness and has investigated the Vandenberg red square. The reported UAP event - a huge, hovering red square above Vandenberg Air Force Base - was shared at a House hearing in July 2023 by a former Navy pilot.

George Knapp - a UAP journalist. Now chief reporter of an investigation unit at KLAS-TV, his work has received multiple awards, including two Peabody Awards. He has written hundreds of UFO-related news stories and series.

Alexandro Wiggins - a UAP witness. According to a report by George Knapp on KLAS-TV, he is a Navy veteran of 23 years and has witnessed a “Tic Tac” UAP event aboard the USS Jackson in 2023. Wiggins also said his father has worked at Area 51, the Air Force base often linked with UFO theories.

Dylan Borland - a UAP witness and Air Force veteran. With little previous media exposure, not much is known about him.

Image source, EPA

The hearing, called “Transparency Relating to Unidentified Anomalous Phenomena (UAP)”, will focus on concerns about disclosure of UAPs and information held by federal agencies, including the Department of Defense and the intelligence community.

It will also look at how effective the All-Domain Anomaly Resolution Office (AARO) is. This is a congressionally mandated body set up to address UAP issues.

The hearing is organised by the Task Force on the Declassification of Federal Secrets of the Congress Oversight Committee.

"The American people deserve maximum transparency from the federal government on sightings, acquisitions, and examinations of UAPs and whether they pose a potential threat to Americans’ safety," said the task force’s chairwoman Representative Anna Paulina Luna.

Caitlin Wilson
US live editor

Good morning from Washington DC, and welcome to our coverage of the US House of Representatives' hearing on "unidentified anomalous phenomena" - perhaps better known as UFOs.

We're expecting to hear from four witnesses, including two experts and two people who say they have seen unidentified anomalous phenomena (UAP) with their own eyes.

Though it may seem like the stuff of science fiction, the head of the Task Force on the Declassification of Federal Secrets of the Congress Oversight Committee - which is putting on today's hearing - says that bringing this testimony, about a topic often shrouded in mystery or conspiracy theories, is all about delivering government transparency to the American public.

You'll be able to watch the proceedings at the top of this page, and we'll bring you any out-of-this-world updates in this feed as well, so stick with us.