Lay-person's article is HERE and for those interested the Scientific Paper.The graphite is older than the zircon containing it, the researchers said. They know the zircon is 4.1 billion years old, based on its ratio of uranium to lead; they don't know how much older the graphite is.
The research suggests life in the universe could be abundant, Harrison said. On Earth, simple life appears to have formed quickly, but it likely took many millions of years for very simple life to evolve the ability to photosynthesize.
The carbon contained in the zircon has a characteristic signature -- a specific ratio of carbon-12 to carbon-13 -- that indicates the presence of photosynthetic life.
"We need to think differently about the early Earth," Bell said.
This data puts the earliest evidence for life back 300 million years and the fact, as noted above, that it's photosynthetic life, suggests life had been around awhile to evolve. Considering that the earth is only 4.54 billions of years old, this adds to an idea that I have always had - as soon as conditions were such were life could form, life did form. Anyway, pretty cool.