School of Rocks
Published Oct 1, 2006 12:00 AM
Copyright ©Greg Clarke '82
Sometimes, science doesn't take the straight route to a breakthrough. And research in one field can link to another far, far away from the original point of inquiry. Another planet, for example.
That's the fascinating trip UCLA paleobiologist J. William Schopf and his colleagues took in producing the first three-dimensional images of ancient fossils — 650 million to 850 million years old — preserved in rocks. Ironically, this novel exploration into Earth's distant past offers exciting promise in the search for life on a distant neighbor — Mars.
If a future space mission to the Red Planet brings rocks back to Earth, Schopf, who also serves as director of UCLA's Institute of Geophysics and Planetary Physics Center for the Study of Evolution and the Origin of Life, believes the two new approaches he and his team applied to microbiology could give scientists a detailed look at microscopic Martian fossils inside the rocks to search for signs of life, such as organic cell walls. The first technique, confocal laser scanning microscopy, involves shining a laser on fossil-bearing rock, in which the organic matter fluoresces the way a white T-shirt under a black light does. First used by biologists to study living cells, this is the first time confocal laser scanning has been applied to geology.
The second approach, Raman spectroscopy, measures how the wavelength of light scattered from the fossil differs from that of the laser. And that's been used primarily by chemists until now. Several years ago, a proposal to use Raman spectroscopy to study minerals on Mars gave Schopf the idea of applying it to microfossils.
Seek Out New Life
With the breakthrough, "We can look underneath the fossil, see it from the top, from the sides, and rotate it around," says Schopf, adding, "I have wanted to do this for 40 years."
Work on early life naturally connects to astrobiology — a field of study aimed at finding life elsewhere in the Universe and understanding what it might be like. If Earth's history is any guide, simple life emerges easily, but complex plants and animals take billions of years to evolve. As Schopf puts it, Earth "is a planet that, for most of the history of life, has been dominated by pond scum."