NASA scientists reckon there are at least a trillion planets just like the Earth out there to be discovered, according to agency boss Bill Nelson.

Speaking at an official briefing about NASA’s involvement in the study of Unidentified Aerial Phenomena [UAPs], Mr Nelson says that one of the agency’s core missions is to search for extraterrestrial life.

He says that while there is no conclusive evidence that UAPs – what we used to call UFOs – are extraterrestrial in origin, the inquiry goes on, using both human observation and AI analysis.

READ MORE: Cattle mutilation mystery ‘could be solved by alien bodies in Mexico’

He says that somewhere out in the galaxy, there will be a planet with the same basic size and composition of the Earth, orbiting a star not unlike our sun at a distance that allows for life as we know it. NASA’s Nicola Fox called it “Earth 2.0”

Mr Nelson says that NASA research based on findings from the James Webb space telescope suggests that there are at least a trillion Earth-like planets.

“In a universe that is so vast – of course I believe that there is a replication of Earth somewhere out there,” Mr Nelson said.

Astrophysicist Frank Drake developed an equation in the 1960s that was intended to estimate the number of advanced civilisations likely to exist in the Milky Way. NASA’s new estimate puts at least one number in for mathematicians to help solve that equation.

Responding to suggestions of a UFO cover-up, Mr Nelson said that if NASA finds aliens “you bet your boots” the public would be told about it.

The director of NASA’s UAP inquiry will not be named publicly, officials said, because of the potential threat from “fringe elements”.

The agency has urged private, commercial and military pilots to report UFO sightings, and stressed that there would be an end to the historical “stigma” about these claims.

While most sightings would be likely to be explainable as “conventional” events, such as mistaken identification of aircraft, balloons or natural phenomena, NASA experts stressed the need for as many reports of sightings as possible.

To get more stories from Daily Star delivered straight to your inbox sign up to one of our free newsletters here .