Science: Zircons are nearly indestructible microscopic crystals that contain traces of the material that was around them when they formed. Some zircons date to 4.4 billion years ago, well before the oldest known rocks. Now Elizabeth Bell of UCLA and her colleagues have found a zircon that formed 4.1 billion years ago whose trace of carbon isotopes could indicate the presence of organic life. If confirmed, the finding would put the origin of life 300 million years before the current first known life-forms on Earth. However, Bell's team acknowledges that several nonbiological processes could also explain the presence of the isotopes.
