Some of the world's finest scientific minds have assembled to discuss the question of UFOs.
Eminent academics and scientists are attending a two-day conference in London organised by the Royal Society - the UK's national academy of science.
World leading astronomers, biologists and astrophysicists including professor Colin Pillinger, principal investigator for the British Beagle 2 Mars lander project, will address questions such as: What will alien life look like if we find it? Will we be meeting life-forms incredibly similar to ourselves or will they be the frightful monsters of sci-fi films? How do you break news of alien discoveries to the world without creating wide-spread pandemonium?
Professor Paul Davies, director of BEYOND: Center for Fundamental Concepts in Science, will discuss man's search for extra-terrestrial life and the consequences for science and society.
Speakers will also include representatives from Nasa, the European Space Agency and the UN Office for Outer Space Affairs. Martin Rees, President of the Royal Society and Astronomer Royal will also be chairing one of the sessions.
The discussion meeting 'The detection of extra-terrestrial life and the consequences for science and society' is the first to take place in the Royal Society's 350th anniversary year.
Astronomers are now able to detect planets orbiting stars other than the Sun where life may exist, and living generations could see the signatures of extra-terrestrial life being detected.
Should it turn out that we are not alone in the universe, it will fundamentally affect how humanity understands itself and we need to be prepared for what will follow.
Highlights of the conference include palaeontologist professor Simon Conway Morris on predicting what extra-terrestrial life might be like and preparing for the worst and Nobel prize winner Christian de Duve on life as a cosmic imperative.
Professor Davies, a physicist from Arizona State University, will conclude the meeting with a public lecture 'The Eerie Silence: are we alone in the universe?'