Professor's alien life 'seed' theory claimed
The remains of living matter have been found in interstellar dust clouds
New evidence from astrobiology "overwhelmingly" supports the view that life was seeded from outside Earth, a scientist has claimed.
Prof Chandra Wickramasinghe of Cardiff University says the first microbes were deposited on Earth 3,800m years ago.
The astrobiologist has helped developed the panspermia theory which suggests an extra-terrestrial origin for life.
He argues for a cycle of life as microbes find their way into comets and "multiply and seed other planets".