The Solar System and the Asteroid Threat
On September 11-13, 2013, an international seminar “The Solar System and the Asteroid Threat” will take place at the HSE. Mark Boslough, Professor at the University of New Mexico and a member of the technical staff at Sandia National Laboratories, and Roberto Furfaro, Professor at the University of Arizona and the head of the Space Systems Engineering Laboratory, will speak on the issues. The event is being organized by the Research Laboratory of Space Research, Technologies, Systems, and Processes at the HSE. Mark Boslough gave a special interview to the HSE news service.
— The joint project " Space Exploration and Technology" is partly devoted to the development of managed space missions and missions of protection when the asteroid and comet impact hazard. Most people usually think of asteroid danger while watching a horror movie or a film like Melanholia by Lars von Trier. How could you describe your research project to non-scientists?
— My research in this area has primarily involved the phenomenon known as airbursts. These are explosive events that are caused by the conversion of kinetic energy to thermal energy when a small asteroid or comet interacts only with an atmosphere but is not large enough to reach the ground intact to form a large crater. The most famous example of a terrestrial airburst is the 1908 Tunguska event, which I think was caused but an asteroid about 40 meters in diameter with an effective explosive yield equivalent to about 3 to 5 Megatons. The explosion over Chelyabinsk was caused by an asteroid with a mass about 10% as big as the Tunguska object, so it was only about 10% as powerful. Comet Shoemaker-Levy 9, which was discovered 20 years ago and collided with Jupiter in 1994, is an example of an airburst on another planet. This event helped us understand the airburst phenomenon and how important it is to include it as part of the NEO threat to our own planet.
— You said that the meteorite in Сhelyabinsk on February, 15, 2013 was going to be a benchmark and the first steps after that was building a computer model of this event. Did it happen already? Have you been involved in computer modeling of the fiery trail and blast? Could you please provide some update on that largest after Toungouska meteorite?
— I consider this to be a benchmark because, unlike Tunguska, it is so well documented and observational data can be used to guide and validate the computer models. We are in the process of modeling this event, and are working to make sure that our models agree with the data in all respects. This is work in progress and our models continue to improve. We hope to publish our preliminary results soon.
— You believe that comet and asteroid impact risk—at its core—is primarily a climate-change risk. You raise scientific and public attention to climate change as a looming national security threat. What international steps should be undertaken to avoid that threat? How do you see a role of researchers in this process?
— In the earliest comet and asteroid impact probabilistic risk assessment papers, back in the early 1990s, scientists recognized that the largest contribution to the overall threat was from asteroids greater than about 1.5 km in diameter because they would be expected to cause a global ecological collapse due to a “nuclear winter” type climate change. Even though the exact mechanism of global catastrophe was not (and is still not) completely understood, it was recognized that climate disruption was the primary cause. I argue that we should apply the same conventional probabilistic risk assessment methods to human-caused global warming that we apply to the asteroid threat. The primary focus should be on reducing the likelihood of global catastrophe by minimizing human-caused changes to the atmosphere that damage its ability to maintain a stable climate and habitable planet.
— How is your cooperation with Russian researchers being developed? What are your expectations and goals on joint work with the HSE colleagues in Moscow?
— I have attended many international meetings on planetary defense and the science of impacts and airbursts (including a 2008 conference in Moscow on the centennial of the Tunguska event). I have exchanged information with my Russian colleagues on the nature of airbursts and their contribution to the impact threat. I think the Chelyabinsk event provides an opportunity to relate computer models to observations, and hope to work with my Russian colleagues to understand it and reduce the threat from similar airbursts in the future.
Anna Chernyakhovskaya, specially for HSE news service