A controversial scientist says he has overwhelming evidence that life was brought to Earth from space. Professor Chandra Wickramasinghe claims life was delivered by comets. That presumably means we are all aliens.

The professor is an astrobiologist at Cardiff University and has spent years investigating a cosmic origin for life. He used data from Nasa missions to comets including Deep Impact for his research.

Professor Wickramasinghe says his calculations show that it is one trillion trillion times more likely that life began inside a comet than on Earth.

He has created computer models suggesting that comets are full of porous clay particles that can hold water liquid in which organic material are nurtured for millions of years.

Comets are balls of ice and dust that travel round the Sun from the edge of the solar system. Collisions with our planet were frequent in the early days of the solar system and we still pass through dust scattered by comets as meteor streams throughout the year.

Professor Wickramasinghe said: “Comets and the warm, watery clay pools in comets are settings in which the organic molecules are transformed into living structures.

“The odds of life starting on Earth rather than on a comet are now calculated as around one trillion trillion to one against. The conditions inside the comet can act as perfect incubators for early life.”

The professor has sparked controversy before by claiming that flu epidemics begin on Earth following brushes with passing comets. He drew up his theories about life’s origins in space – called panspermia – when he worked with the late, famous British astronomer Fred Hoyle.

Professor Wickramasinghe added: “Life is like an infection that spread out across the galaxy. People are essentially aliens and life on Earth is a cosmic phenomenon.” A report by the professor and his team or researchers is to appear in the International Journal of Astrobiology.

Last year, scientists in India sparked controversy by claiming they had found particles of alien life in a shower of red rain.

The photo of Comet Hale-Bopp was taken by Paul Sutherland.

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