Dr. David Morrison is senior scientist at the NASA Astrobiology Institute and a founder of the multidisciplinary field of astrobiology. He is an expert on the risk of asteroid impacts and potential ways to mitigate that risk.

NASA Tech Briefs: What is astrobiology?

Dr. David Morrison: Astrobiology is the study of the living universe. It's very broadly based. It involves understanding the origin, evolution, distribution, and future of life in the universe.

NTB: You have to be an expert in a lot of areas to cover all of that territory, don't you?

Dr. Morrison: You have to have friends who are experts that you can talk to. Astrobiology is inherently a multi-disciplinary field, which means that we do try to bring the perspectives of different scientists into addressing the same problems, hoping that we'll get answers that are more than just the sum of the individual parts.

NTB: How does one go from being an astrobiologist to becoming an expert on the potential hazards of asteroid impacts?

Dr. Morrison: Asteroid impacts and astrobiology are related in terms of the history of Earth, because impacts, after all, have been an important driver for evolution, at least in the well-documented case of the impact that did in the dinosaurs 65 million years ago. So there is a connection; however, I wouldn't want to stretch that too far. Worrying about the impact hazard today is only loosely related to astrobiology.

NTB: You just mentioned the dinosaurs. While testifying before congress in 2002, you stated, "The impact of an asteroid about 10 miles in diameter 65 million years ago not only ended the existence of the dinosaurs, it wiped out 99-percent of all life on Earth." Recently there's been much debate within the scientific community about whether it was, in fact, an asteroid that killed off the dinosaurs. Are you still convinced that it was an asteroid?