Popular Physicist Says , "We are alone in the universe"

The process which led to the creation of humankind on earth was a fluke - and it is highly unlikely it has been repeated anywhere else in the universe.

That is the view of English physicist Professor Brian Cox, who made the assertion in an episode of BBC's Human Universe.

Professor Cox thwarted suggestions alien life was a possibility and said he believed humans were the only form of life in the universe, despite the astronomical number of other planets in the galaxy.

The presenter and scientist, who also appeared on the ABC's Q&A program last week, blamed a series of "evolutionary bottlenecks" as the main reason no extraterrestrial life has been discovered.

"There is only one advanced technological civilisation in this galaxy and there has only ever been one - and that's us," Professor Cox said. "We are unique.

"It's a dizzying thought. There are billions of planets out there, surely there must have been a second genesis?
"But we must be careful because the story of life on this planet shows that the transition from single-celled life to complex life may not have been inevitable."

Professor Cox went on to say that the extinction of dinosaurs, believed by scientists to have been caused by a meteor impact, allowed mammals and ultimately humans to dominate the planet.

"We still struggle to understand how this happened," he said. "It's incredibly unusual.

"We're confident this only happened once in the oceans of the primordial earth. Life here did squeeze through."

Professor Cox's views are in stark contrast to those of astrophysicists Dr Timothy Brandt and Dr David Spiege of Princeton University, who last month made the claim that our best chance of finding aliens, if they exist at all, lies in the examination of plant life on planets outside our solar system, known as exoplanets.

They said if alien life existed on exoplanets, it might be possible to detect traces of water, oxygen and chlorophyll.

Meanwhile, NASA has offered a more widely accepted prediction; that one hundred million worlds in our galaxy are capable and fit to host alien life.