No. 13: Winter 1981
The oldest fossils found so far are dated at 3.5 billion years ago. Discovered in Australia, these life forms seem to have been capable of synthesizing their own food, much like present-day plants. In other words, these life forms were not so primitive after all. If we are to assume that still simpler life and pre-life chemical evolution preceded these fossils, the advent of life on earth must be pushed back much farther to allow time for gestation.
(Anonymous; "Oldest Life-Forms May Have Made Own Food," Eos, 61:578, 1980.)
Comment. Another possibility is that life did not originate on earth and was instead brought here on comets, meteorites, etc.