Date: August 20, 2011

Title: David Kring: Making an Impact on Earth and the Moon

Podcaster: Nancy Atkinson

Organization: NASA Lunar Science Institute (NLSI)

For more information about Dr. Kring and a list of his past publications, please see

Music: “You’re the Weather” by Ben Bedford’s “Land of the Shadows” CD. Used by permission.

Description: David Kring is a noted lunar scientist but is also well known for another discovery: he was part of the team that discovered the Chicxulub impact crater, and Kring and his team worked to link the crater and its ejecta to the K-T boundary mass extinction of dinosaurs and over half of the plants and animals that existed on Earth 65 million years ago.

Bios: The NLSI brings together leading lunar scientists from around the world to further NASA lunar science and exploration.

Dr. David Kring leads the Center for Lunar Science and Exploration, which is part of the NASA Lunar Science Institute. Kring received his Ph.D. in earth and planetary sciences from Harvard University. He specializes in impact cratering processes produced when asteroids and comets collide with planetary surfaces.Kring has been actively engaged in communicating scientific issues to the public through a variety of print, radio, and television forums, including popular science books, magazine articles, and science documentaries for the Discovery Channel, Learning Channel, History Channel, PBS, Channel 4 (U.K), and NHK (Japan).

Nancy Atkinson is a science journalist and is the Senior Editor for Universe Today.

Sponsor: This episode of “365 Days of Astronomy” is sponsored in-kind by Universe Today, your source for space and astronomy news updates since 1999. Find us at


Voice: You are listening to the NASA Lunar Science Institute podcast which highlights the latest news information of the Moon, on the Moon and from the Moon. It is produced from the NASA Lunar Science Institute at the Ames Research Center in Moffett Field, California.

Nancy: Hi, this is Nancy Atkinson for the NASA Lunar Science Instiutute. Today we’re at NASA’s Ames Research Center talking with Dr. David Kring, from NLSI. He is a noted lunar scientist but is also well known for another discovery, he was part of the team that discovered the Chicxulub impact crater, and Kring and his team worked to link the crater and its ejecta to the K-T boundary mass extinction of dinosaurs and over half of the plants and animals that existed on Earth 65 million years ago. He has also studied the environmental effects of impact cratering and shown how impact processes can affect both the geological and biological evolution of a planet.

Thanks for being with us today, Dr. Kring, could you tell us about your involvement in the Chicxulub crater discovery.

David Kring: Yes, actually in the early 1980’s it was hypothesized that the extinction of dinosaurs and most life on Earth 65 million years ago was extinguished by an impacting asteroid or comet, and about ten years later we had the good fortune of discovering the impact point which was an immense impact crater nearly 200 km in diameter on the Yucatan Peninsula of Mexico.

Nancy: Could you explain some of the particulars of how you were able to determine the impact point?

Kring: Scientists, before we got involved, had detected the chemical fingerprints of that impact at various locations around the world, and what we did was focus our attention on the re-deposits that would have been ejected from the crater, portions of the Earth’s crust that was excavated from the crater as it was being formed and re-deposited on the surrounding landscape. This being such a big impact event, this material actually covered a large part of the Western Hemisphere and we had the opportunity to go to Haiti in the late 1980s and detected nearly a meter of that material on the island of Haitia. That told us that somewhere in the Gulf of Mexico region was the point of impact and that led us to the structure on the Yucatan Peninsula.

Nancy: Now, how does this work relate to lunar science or how did it impact your career?

Kring: Interestingly enough, I started my career as an undergraduate student studying Apollo samples, some of which were affected by impact processes. That was my first exposure to the concept of asteroids or comets impacting planetary surfaces and damaging those surfaces and altering them in some very interesting ways. I then went off and began to study other things like the origin of the solar system, which at the time fascinated me, but then there was this very big question about the extinction of dinosaurs, this dramatic change and evolution of life on Earth and it captured my attention. And I put to use those old tools, so those things I had learned about cratering processes the Moon were then applied to this questions here at home on Earth.. So I always say the discovery of the Chicxulub crater is one of the most interesting and perhaps even most important contributions that planetary science has made to terrestrial science. We now understand because of the discovery that impact catering not only affects the geological evolution of a planet, it affects the biological evolution of the planet and that is as a huge change in the way we think about our own existence and the existence of life on our planet.

Nancy: So you are typical of all young people, you liked dinosaurs and space,

Kring: Yes, I certainly did like dinosaurs and I still like space. I have to say, I often times have opportunities to speak to younger school age children about this, and that is actually frightful! I used to know a lot more about dinosaurs than I do today, and there no more knowledgeable about dinosaurs than a fourth grade student!

Nancy: What are some of the advances in knowledge that we’ve gotten about impact craters on the Moon.

Kring: Ahh! One of the problems that just vexes us here on Earth is the impermanence of the impact cratering record. Impacting objects are constantly peppering the Earth’s surface but we have these other geological processes; we have volcanism, we have weather, which causes erosion. Of course we have seas that cover a big percentage of the planet, and so the understanding of what these impacting objects have done to the planet is imperfectly preserved. The Moon, in contrast, has none of these geologic processes and so if you actually want to get a measure of the cadence of these types of impact events and the distribution of small versus life-altering ones, you have to go to the Moon. So that is in fact at the core of Earth studies of lunar impact events we are trying to find the tempo of these life-altering impact events. We will do that on the Moon but it has direct application to the evolution of our own planet Earth.

Nancy: Can I ask you how important to you think a is lunar sample return would be as far as going someplace where there was an impact and getting that back?

Kring: Lunar sample return is absolutely essential and what we have to do, is we have to land on the lunar surface, we have to collect a sample that was melted by an impact event and analyze it in our laboratories. And while we are at it, we will collect samples of other things nearby and learn about all sorts of interesting things like how the Moon formed, how it might have formed from the Earth and so those types of missions are incredibly exciting for a variety of reasons, but it is important to bring samples back to Earth and once they are here people like myself and our students can study these things literally for decades.

Having said that, it is so frustrating that we aren’t getting to the Moon sooner and bringing samples back. I mean, it has been 40, it is getting closer to 50 years since we’ve actually brought samples back. It is as if we’ve said in this country, let’s stop learning and that is just, in my mind a travesty and a tragedy and it is not the type of thing that I think Americans would really want if they actually thought about it.

Nancy: Exactly, I agree with you. Well, Dr. David Kring, thank you very much for being with us today.

Kring: My pleasure.

Voice: To find out more about this topic, visit our website at Any opinions expressed are the individuals and do not necessarily reflect the opinion of NASA or the NASA Lunar Science Institute. This podcast is produced for educational purposes only. On behalf of the NASA Lunar Science Institute, thanks for listening.

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