If a future space mission to Mars brings rocks back to Earth, Schopf said the techniques he has used, called confocal laser scanning microscopy and Raman spectroscopy, could enable scientists to look at microscopic fossils inside the rocks to search for signs of life, such as organic cell walls. These techniques would not destroy the rocks.
"It's astounding to see an organically preserved, microscopic fossil inside a rock and see these microscopic fossils in three dimensions," said Schopf, who is also a geologist, microbiologist and organic geochemist. "It's very difficult to get any insight about the biochemistry of organisms that lived nearly a billion years ago, and this (confocal microscopy and Raman spectroscopy) gives it to you. You see the cells in the confocal microscopy, and the Raman spectroscopy gives you the chemistry.
"We can look underneath the fossil, see it from the top, from the sides, and rotate it around; we couldn't do that with any other technique, but now we can, because of confocal laser scanning microscopy. In addition, even though the fossils are exceedingly tiny, the images are sharp and crisp. So, we can see how the fossils have degraded over millions of years, and learn what are real biological features and what has been changed over time."
His research is published in the January issue of the journal Astrobiology, in which he reports confocal microscopy results of the ancient fossils. (He published ancient Raman spectroscopy 3-D images of ancient fossils in 2005 in the journal Geobiology.)
Since his first year as a Harvard graduate student in the 1960s, Schopf had the goal of conducting chemical analysis of an individual microscopic fossil inside a rock, but had no technique to do so, until now
Contact: Stuart Wolpert
University of California - Los Angeles