UFOs: Five revelations from Nasa's public meeting

A Nasa panel investigating unidentified flying objects has collected around 800 mysterious reports - but only a small fraction are truly unexplained, researchers say.

The agency set up the panel last year to explain its work on what it calls unidentified anomalous phenomena (UAP).

UAP are defined as sightings "that cannot be identified as aircraft or known natural phenomena from a scientific perspective".

The panel, which will issue a report later this year, held its first public meeting on Wednesday.