Two tiny bodies nestled in display cases under the full glare of the world's media. Three-fingered hands, elongated heads. Proof, says Jaime Maussan, that "we are not alone".

The Mexican ufologistSomebody who investigates Unidentified Flying Objects. claims these are fossilised alien remains discovered in Peru in 2017. Experts told members of the Mexican parliament that analysis found no human DNA. And x-rays reveal they contain "eggs" and metal implants.

The footage is astonishing. But viewers online mocked the photos, noting the close resemblance to Steven Spielberg's ET. And scientists are sceptical. NasaThe National Aeronautics and Space Administration, responsible for the US space programme. astrophysicistScientists who try to understand the contents of the universe. David Spergel invited Maussan to "make samples available to the scientific community".

Spergel was presenting a long-awaited Nasa report into Unidentified Anomalous Phenomena, commonly known as UFOs. In April, the US government said it was tracking over 650 sightings. But Spergel and his colleagues said there is no evidence aliens are behind them.

However, the report did not rule out the possibility that "alien technology" operates in the Earth's atmosphere. Nasa boss Bill Nelson says the agency is taking aliens "seriously", appointing a new director to study UFOs.

Despite the scorn and scepticism, many believe there is something out there. US pilot Kenneth Arnold spotted the first "flying saucer" in 1947, starting a UFO-spotting craze. Today, over 100 million Americans think galactic travellers have visited Earth.

During the Cold WarA period of diplomatic conflict between blocs led by the USA and the USSR that lasted from 1947 until 1991, when the USSR collapsed., the US Air Force kept data classifiedInformation that is labelled as top secret, only to be shared with certain people. . Many sightings were military hardware, like U2 spy planes. This secrecy fed conspiracy theories that authorities were hiding evidence of alien encounters.

Astronomer Chris Impey says UFOs were a "taboo" topic among scientists - too closely associated with science fiction, amateur enthusiasts and elaborate hoaxes. For example, previous claims by Jaime Maussan have been debunked.¹

Scientists are more confident about the existence of life on other planets. There are an estimated 300 million habitable worlds in our galaxy, and astronomers believe it is highly unlikely we are the first advanced civilisation.

But scientists are starting to take UFOs more seriously. Nasa's Daniel Evans says they want to "move from conjectureA theory or guess based on incomplete information. and conspiracy towards science and sanity". The agency asks the public to help with a phone app to record sightings.

Science writer Joel Achenbach says a new "UFO mania" is taking hold. In 2021, leaked US military videos appeared to show alien spacecraft disappearing into the sea. And in June, a former intelligence officer alleged the US had acquired alien vehicles. 

Achenbach is unconvinced. There's a lot of excitement and a few eyewitnesses. But no data and nothing for scientists to work with. Until we have a spaceship or non-human DNA to scrutinise, UFO research is just a "distraction" from all our real problems.

So scientists want to see whether Maussan will let them examine his "alien corpses". If genuine, they would be the most significant discovery in the search for alien life.

Yes: Of course. The universe is a vast and extraordinary place, full of surprises. So, we should take any discovery seriously, especially if it may tell us about the existence of intelligent alien life.

No: This is not science. It is a media stunt organised by people who want to believe something exists. Serious research involves examining evidence, testing theories, and sharing results publicly.

Or... Critical thinking is about separating facts and opinions. Nasa says there is no evidence of UFOs with alien origins, but it cannot rule out the possibility aliens exist. This is a cautious and serious approach.

Ufologist - Somebody who investigates Unidentified Flying Objects.

Nasa - The National Aeronautics and Space Administration, responsible for the US space programme.

Astrophysicist - Scientists who try to understand the contents of the universe.

Cold War - A period of diplomatic conflict between blocs led by the USA and the USSR that lasted from 1947 until 1991, when the USSR collapsed.

Classified - Information that is labelled as top secret, only to be shared with certain people.

Conjecture - A theory or guess based on incomplete information.