����ý

Nasa has been looking into reports of mysterious sightings in the skies and it says it's not found any concrete evidence they are aliens... but admits it's possible that they could be.

The space agency says there's "a lot more to learn" about UFOs - or Unidentified Anomalous Phenomena (UAPs), as it calls them - as it presented a report following a long-awaited study into hundreds of reports of sightings.

The Nasa experts said there was no evidence that UAPs came from outer space, but they admitted that they didn't know exactly what many of them are or what witnesses and recordings actually showed.

The report says most UFO sightings have been explained, but there are a small handful which cannot be immediately identified as "known human-made or natural phenomena."

What's a UAP vs a UFO?

Whilst often they are called UFOs - Unidentified Flying Objects - by the public, space experts now prefer to use the term UAP which stands for Unidentified Aerial Phenomena.

Some experts feel that after years of movies and books, UFOs make people think of science-fiction and not scientific study.

UAPs can be anything from an odd sighting in the sky, to aircraft being used in the wrong way.

Last year, Nasa announced that they were putting together a new team which would investigating sightings and making a plan for dealing with future UAPs.

The team, made up of a variety of scientists, were all experts in different subjects including aviation, space travel, planets and even medicine and the oceans.

What did the UAP report say?

Today's report, put together by these experts, looked at many of the cases that couldn't be explained.

They claimed that, although they found no evidence that aliens are behind them, the space agency also said it couldn't always rule that possibility out.

Nicola Fox, from Nasa's Science Mission Directorate, said: "UAP are one of our planet's greatest mysteries.

"And it's really due to the limited number of high quality data that surrounds such incidents," she explained.

Nasa also announced it has appointed a director of UAP research, and that they will use artificial intelligence (AI) and improved technology to investigate any future UFO data.

The experts were clear that although Nasa doesn't know what these UAP are, it's doing what it can to find out.

How can the public get involved in UAP mysteries?

Also Nasa said that it wants the public to get involved in UAP research.

"There's a wealth of data that cell phones take," said David Spergel, the chair of the UAP independent study team, in response to one of a question.

He suggested that apps could collect phone data and help researchers. It's "an opportunity to engage the broader public in doing science," Spergel said.

So keep watching the skies - and keep your phone handy!