INTERSTELLAR DELIVERY: The panspermia hypothesis states that life was carried to earth by comets or asteroids, like the Gaspar Asteroid shown here.
> (Source: NASAWikipedia Commons)

Sir Fred Hoyle, a British astronomer of worldwide reputation in the 20th century, was  a proponent of the panspermia hypothesis.

Hoyle’s scientific honors were numerous. In 1957, he was made a Fellow of the Royal Society, England’s venerable 350-year-old scientific body whose past members include Isaac Newton, Lord Kelvin and Robert Hooke. In 1972, he was knighted in recognition of his achievements. Although the Nobel Prize eluded him on two occasions — being instead shared by Hoyle’s co-worker William Fowler and Subramanyan Chandrasekhar in 1983 — he is credited with significantly advancing our understanding of various astronomical phenomena. Those range from nucleosynthesis and the dispersal of heavy elements via supernovae to the structure of pulsars.

Hoyle was an iconoclast who did not fear taking the unexpected position on issues thought settled. Most famously, he staunchly opposed the Standard Cosmological Model, known as the “big bang” after a comment by Hoyle himself. Instead, he favored a steady-state cosmos like the one assumed by Einstein to exist before the discovery that light from distant galaxies was shifted to the red end of the spectrum, implying a cosmic expansion.

He also remained unconvinced by the hypothesis that chemical evolution was sufficient to explain the emergence of life on Earth, instead arguing for interstellar clouds themselves as cradles of microbial life.

Along with Chandra Wickramasinghe, director of the Cardiff Centre for Astrobiology in Wales, Hoyle developed the modern notion of panspermia. Hoyle argued that comets may act as microbe carriers and that biotic evolution cannot be fully understood without the recognition that there is a regular influx into the system of viruses dispersed by comets. These ideas, unlike his work on stellar fusion, have yet to find wide acceptance.

Hoyle’s type of disagreement with the assumption of unaided chemical evolution on Earth has been criticized by Oxford University zoologist and science writer Richard Dawkins, among others. Dawkins argues in The Blind Watchmaker that this view is subject to a misapprehension about the emergence of enzymatic complexity inasmuch as it is equated with chance. Hoyle thought the possibility that cellular life could have emerged on Earth by chance to be nonsensical.

Dawkins writes that natural selection moves up a ladder of evolutionary stages in which useful adaptations are preserved at each stage, so that any critique of the likelihood that the end product will be arrived at wholly by chance is beside the point. With this view of evolution, it is not necessary to look to extraterrestrial sources to explain the rapid emergence of cellular life on Earth.

William Orem is Science Editor at Science and Theology News