A top Harvard astrophysicist has claimed that Earth has been visited by extra-terrestrial life in the past, as research in the US continues into the possibility of alien life forms.
In 2022, NASA launched their Unidentified Anomalous Phenomena Independent Study, in which an assembled panel begun analysis to roadmap unidentified anomalies.
NASA administrator Bill Nelson has previously admitted to his belief that there is other life within the universe.
Speaking about the UAP study in 2022, Nelson said there is a "global fascination" with unidentified objects and the belief of alien life.
Avi Loeb claims extra-terrestrial life forms have visited earth in the past
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Nelson stated: "There's a global fascination with UAP. On my travels, one of the first questions I often get is about these sightings. And much of that fascination is due to the unknown nature of it.
"If you ask me do I believe there's life in a universe that's so vast that it's hard for me to comprehend how big it is, my personal answer is yes."
Speaking to GB News, astrophysicist Avi Loeb agreed that there is every possibility of extra-terrestrial life, and that the Earth may have been visited before the human race existed.
Loeb stated that Earth has existed for 4.6 billion years, but humans have only existed "over the past two million years".
Loeb explained: "We came just at the end of this history of the Earth, and throughout our history there might have been visits.
"For example, the Earth very abruptly started to have oxygen in its atmosphere. We don't understand why. And 252million years ago, the Earth went through a global warming event of the type that we are now producing with our technologies.
"And so the question arises as to whether any of these sudden changes in the history of Earth could have been triggered by visits."
Loeb went on to criticise those who deny the existence of other life, and stated that "reality bites" those who deny that other life does not exist in the wider universe.
Avi Loeb says the human race should 'search for neighbours' in the universe
GB News
Loeb told GB News: "What I would like to say about our cosmic neighbourhood is that reality bites those who deny it.
"The best approach is to adapt to the reality and figure out you know what it is, rather than ignore it or deny it and say there is nothing out there.
"That is a very arrogant approach to say we know everything. We are the only smart beings that existed since The Big Bang. I don't think so.
"I think we should search for neighbours and from that we will learn new things."