Stephen Hawking's terrifying UFO warning resurfaces as 'hostile alien threat' identified by Harvard scientist

A terrifying warning from Stephen Hawking has resurfaced after Harvard researchers published a paper speculating that a comet could be a 'potentially hostile' alien object.

Last month, Harvard University researchers Avi Loeb, Adam Hibberd and Adam Crowl published a paper which suggested that comet 3l/ATLAS could be a reconnaissance probe sent by a technologically advanced alien civilisation watching our planet.

"The hypothesis in question is that [31/ATLAS] is a technological artefact, and furthermore has active intelligence. If this is the case, then two possibilities follow," the group wrote in the paper.

"First that its intentions are entirely benign and second they are malign." The researchers added that in the event of an attack it'd 'require defensive measures to be undertaken'.

It's worth noting that the researchers, as well as NASA scientists, have since stressed the most likely scenario is that 3l/ATLAS is just a comet.

A research paper discussing a 'potentially hostile' alien object has sparked discussion about UFOs again (Getty Stock Images)

But should the 'most likely outcome' of 3l/ATLAS not being a 'completely natural interstellar' object turn out to be false, then late physicist Stephen Hawking has a sobering warning to remind us why we shouldn't rush to welcome alien arrivals to Earth.

Prior to his death in 2018, Hawking had stressed numerous times about the dangers of reaching out to more technologically advanced civilisations, as they may not have peaceful or benevolent intentions.

"If aliens ever visit us," Hawking explained in an episode of Into the Universe back in 2010, "[Then] outcome might be similar to when Columbus landed in America, which didn’t turn out well for the Native Americans.

"We only have to look at ourselves to see how intelligent life might develop into something we wouldn’t want to meet," he continued.

The Cambridge researcher believed that an advanced alien civilisation capable of cruising through the cosmos would've likely have exhausted the materials on their own planet, and be on the lookout for other plants to colonise for resources or move to.

However Stephen Hawking believes if aliens are out there we should be staying very quiet (Bruno Vincent/Getty Images)

This wasn't the only time which Hawking warned against reaching out to alien civilisations, with the 76-year-old drawing a line between establishing that other planetary civilisations exist and offering an olive branch.

Hawking's warnings relate to a theory known as the 'Dark forest hypothesis'.

'Dark forest hypothesis' explained

The 'Dark forest hypothesis' suggests that several alien civilisations are out there, however no one wants to be the first to put themselves forward due to fears or alerting even more advanced civilisations to their location.

Which means if aliens are out there and beginning to make themselves known, we shouldn't be welcoming them to Earth with open arms, unless we want to live out a War of the Worlds type scenario.