Why is Asteroid 2012 DA14 Important to Monitor?
In a few weeks Asteroid 2012 DA14 will be in our neighborhood. We have received numerous inquires on this momentous event and have put together the following FAQ for you. Now you can impress your friends with all this information!
What is Asteroid 2012 DA14 and how close will it come to Earth? Asteroid 2012 DA14 (DA14), discovered in February 2012, is scheduled to fly past Earth on February 15, 2013. While it will not impact the Earth, it will fly just 17,000 miles above the Earth’s surface at about five miles per second.
What is known about DA14? How big is it? DA14 is about 160 feet in diameter, making it about the same size as an office building. Two famous asteroid impact sites on Earth were caused by asteroids about the same size (or even a bit smaller) than DA14. Both Meteor Crater in Arizona and the impact in Tunguska, Siberia on June 30, 1908 were caused by roughly 140-foot asteroids. The blast wave from the Tunguska asteroid flattened about 1000 square miles of forest.
How long ago did we learn of DA14 and its impending close flyby of Earth? DA14 was discovered on February 13, 2012, just one year in advance of its close flyby of Earth. Had it been on a collision course with Earth on February 15, 2013, there would not have been enough time to prepare a mission to deflect it. While we would have been able to accurately predict its impact location on Earth, our only possible response would have been to evacuate the area and hope for the best.
How many asteroids similar to DA14 or larger could threaten Earth? There are roughly a million asteroids larger than DA-14 whose orbits cross Earth’s orbit. We know this because we have only discovered about ten thousand of these asteroids, and we know that current telescopes have only effectively surveyed about one percent of the volume of space in which these asteroids orbit. Therefore we have only discovered about one percent of these asteroids!
Why is B612’s Sentinel Space Telescope so important? Sentinel is designed to find and track Near Earth Asteroids—over 90% of the ones larger than 400 feet in diameter—and at least 50% of those 200 feet in diameter. Sentinel will track these asteroids and give us decades of advance warning if any of them will collide with Earth. This is enough warning that we will be able to deflect an impending impact using well developed concepts like kinetic impactors and gravity tractors. Sentinel will enable us to protect the Earth by preventing future asteroid impacts.
Even though the risk of collision from DA14 is extremely low, is there anything that could raise or change the risk of impact for future generations? DA14’s encounter with the Earth is so close that the asteroid’s orbit will be significantly changed—from an asteroid “year” of 366 days to only 317 days. The path will also be changed substantially, but we can calculate what that change will be. DA14 will pass at large distances from the Earth every six to seven years, with the next close approach in February 2047.
Will we be able to study the DA14 asteroid as it passes the Earth? What might we hope to learn about it? The passage of an asteroid at such a small distance from the Earth gives astronomers an unusual opportunity to study it in detail. DA14 will be quite bright, and while probably not visible to the unaided eye, it will be easily detectable with binoculars. Telescopes will be able to collect a lot of information on the size, shape, rotation and composition of DA-14. Radar observations will give us very precise measurements of its orbital track, which will improve our knowledge of its future movements.
Could the DA14 asteroid collide with a GEO satellite and disrupt service? While the trajectory of DA14 brings it closer to the Earth than the communications satellites which orbit at about 21,000 miles overhead, its trajectory as it comes close to Earth is not near the orbits of the geosynchronous satellites. So there is no risk of collision or disruption in service.