Detecting Potentially Dangerous Asteroids & Comets

Things have been progressing nicely in The Planetary Society’s Planetary Defense program that is working towards preventing asteroid impact. Progress has ranged from asteroid observers improving their systems, to asteroid impact public education, to collaboration with the world’s Planetary Defense community.

 The 2015 Shoemaker NEO Grant winners have all gotten their hardware set up using their grants to improve their asteroid observing capabilities.  The six winners spread across 3 countries on 3 continents are amateurs with amazing telescope systems.  They focus mostly on tracking near Earth asteroids, and characterizing them, following up on discoveries made by the larger professional surveys, so that we know what the asteroids’ orbits are and whether they are dangerous, and what the nature of the asteroids are, for example if what looked like one asteroid is actually a binary pair. 

 We have also begun to gear up for another round of grants.  The call for proposals will come out this fall.  We are excited to announce that Dr. Timothy Spahr has once again agreed to serve as the Shoemaker NEO Coordinator.  Tim, a long time asteroid scientist and former Director of the Minor Planet Center which is responsible for organizing the asteroid observations from around the world, helps guarantee that we are making the most impact for the money available.  He also will head the review panel of professionals who will recommend the proposals for funding.

 Our Director of Science and Technology, Dr. Bruce Betts, has been asked to once again serve on the organizing committee for the Planetary Defense Conference (PDC).  The PDC is held every 2 years and brings together the world’s experts on all aspects of planetary defense, from observers, to those developing techniques to move dangerous asteroids when they are discovered, all the way to disaster management experts starting to thinks about how evacuations or disaster relief might be handled in the event of an impact.

 We are also working to ramp up our asteroid threat public education.  One way we currently provide information is through periodic planetary defense related interviews on our weekly Planetary Radio show.  A recent episode interviewed Lindley Johnson, NASA’s Planetary Defense Officer about the recent formation of NASA’s Planetary Defense Coordination Office.

The Planetary Society established the Gene Shoemaker Near Earth Object grant program in 1997. Grants are awarded to amateur observers, observers in developing countries and underfunded professional astronomers.  This allows more eyes on the sky that will increase contributions to Near Earth Object research.  Have you ever wondered how these objects are assessed?  How on earth – or in this case, in space - do you categorize them?

The Torino Scale is one method used for categorizing the impact hazard associated with near-Earth objects and is intended as a communication tool for astronomers and the public to determine the seriousness of collision predictions, by combining probability statistics and known kinetic damage potentials into a single threat value.  

The Torino Scale uses an integer scale from 0 to 10. A 0 indicates an object has a negligibly small chance of collision with the Earth, compared with the usual "background noise" of collision events, or is too small to penetrate Earth's atmosphere intact. A 10 indicates that a collision is certain, and the impacting object is large enough to precipitate a global disaster.

An object is assigned a 0 to 10 value based on its collision probability and the kinetic energy (expressed in megatons of TNT) of the possible collision.

The Torino Scale also uses a color code scale: white, green, yellow, orange and red. Each color code has a meaning as indicated on the scale shown below.

No object has ever been rated above level 4, and currently all objects are rated level 0.

The Chicxulub impact, which many believe was a significant factor in the extinction of the dinosaurs, has been estimated at 100 million megatons, or Torino Scale 10.  Both the Barringer Crater in Arizona and the Tunguska event of 1908 are estimated to be in the 3-10 megaton range.  2013’s Chelyabinsk meteor in Russia was 0.4 megatons, a 0 on the Torino Scale.

Your contributions to planetary defense fund our Shoemaker NEO grant program, allowing our researchers to do critical work – defining NEO orbits to tell whether they are on a collision course with Earth and continuing to discover new NEOs.  With your continued support, this important work can further our knowledge of, and defense from, potentially hazardous near earth objects.