Are we alone in the Universe? That's the question Andrew Knoll, author of Life on a Young Planet: The First Three Billion Years of Evolution on Earth, will ask at this year's Margaret and Herman Sokol Science Lecture on Nov. 3. The event will begin at 8 p.m. in the Alexander Kasser Theater.

Knoll is a leading authority on Proterozoic life (544 to 2,500 million years old), environmental change in the later part of Precambrian time and the rapidly developing field of chemostratigraphy. He has been involved in recent work, with Chinese scientists, on fossil embryos from the earliest Cambrian era. A member of the National Academy of Sciences, Knoll is Fisher professor of Natural History, associate dean of the Faculty of Arts and Sciences, and curator of the Paleobotanical Collections at the Harvard University Herbaria.

In his lecture, Knoll will explain how 21st-century scientists are exploring the solor system and beyond for signs of life. Building on his own research, he will explain how our understanding of biological history on Earth informs the search for life elsewhere, how the 2004 Mars rovers are reshaping astrobiological debate about our planetary neighbor, and how future exploration will carry the search beyond Mars to the outer solar system, nearby stars and the farther reaches of space.

A native of south central Pennsylvania, Knoll is a graduate of Lehigh University and holds a doctorate from Harvard. He specializes in the evolution of prehistoric bacteria, in what he calls the "deep history" of life, going far beyond the unfolding of animal diversity 550 million years ago known as the "Cambrian explosion."

In Life on a Young Planet, Knoll takes readers on a fascinating journey back in time to understand how life on Earth came to be. The book also draws on the latest scientific discoveries, many of them made by Knoll and his students.

Hailed by Time magazine as one of America's best paleontologists, Knoll also has been a science team member for the Mars Exploration Rover missions.

Through a generous gift from Margaret and Herman Sokol, the Margaret and Herman Sokol Science Lectures were established to allow members of the University and surrounding communities to gain a greater appreciation and expanded knowledge of important issues in science.

Each semester, a speaker of national or international renown is invited to MSU to meet with faculty and students, and conduct an evening seminar open to the public. Speakers are selected on the basis of strong interdisciplinary appeal in their area of expertise and public recognition.