Most Active Stories
Thu March 6, 2014
Dr. David Trilling, Northern Arizona University - Can an asteroid impact Earth?
Today's Academic Minute has intergalactic ramifications!
Some close calls have raised the awareness of the threat of asteroids potentially on a collision course with Earth. David Trilling, Assistant Professor of Physics and Astronomy at Northern Arizona University, explains what we can do if we're ever faced with such an interstellar calamity.
David Trilling is an assistant professor of astronomy at Northern Arizona University. He researches the evolution of our solar system and planetary systems with an interest in the properties and monitoring of near-Earth objects. He holds a Ph.D. in planetary science from the University of Arizona.
Asteroids and their Impact
Near Earth objects are comets and asteroids whose orbits bring them close to the Earth. Using telescopes, we can study these objects in space to learn about the evolution of the Solar System.
But what happens if a near Earth asteroid gets too near the Earth? It happens more often than you’d think. In early January, an asteroid was discovered just a few hours before it burned up in the Earth’s atmosphere. Last February, it happened not once, but twice. Astronomers knew months ahead of time that one of the asteroids would fly safely past the Earth.
While our telescopes were tracking that asteroid, a completely unrelated asteroid entered the atmosphere high over the Russian city of Chelyabinsk and exploded, causing extensive damage and injuries – mostly from flying glass. Fortunately there were no fatalities.
Why didn't we see the Chelyabinsk impactor coming? Because that asteroid was coming from the direction of the Sun, no nighttime telescopes could have seen it. We were literally blindsided.
One way to minimize unanticipated impacts in the future would be to launch a space telescope that orbits interior to the Earth and looks back at the Earth for any asteroids on final approach. This could allow a warning time of hours, days, or even longer. With a few hours of warning, many injuries in Chelyabinsk could have been avoided by advising people to stay away from their windows. With a lead-time of years, significant space missions could be launched to deflect the asteroid's path.
The odds of an asteroid impact are very, very low, but not zero. The societal costs of the unexpected impact of a large asteroid can be very, very high. In the near future, we may be able to see dangerous asteroids coming, and prepare long before impact.