WEST LAFAYETTE — For the threat of meteor strikes large or small, early detection is key, and evacuation may be the only defense needed within the next 1,000 years, according to an asteroid impact expert.
The best investment in asteroid defense is not in weapons to deflect them, but in telescopes and surveys to find them, said H. Jay Melosh, co-author of the 2010 National Research Council report "Defending Planet Earth" that explored the feasibility of detecting all Earth-crossing asteroids greater than 140 meters in diameter and ways to mitigate their hazard.
"At this point we've found more than 90 percent of the large, civilization-ending asteroids that cross the Earth's orbit and none are threatening us, which lets us breathe a little easier for the next 1,000 years or so; but there are limits to this search," said Melosh, a professor of earth, atmospheric and planetary sciences and physics at Purdue University.
"We need to invest in telescopes that can find asteroids on Earth's sunward side, our current blindspot, and in programs to find and track the smaller asteroids, which are less devastating but far more likely to strike us."
Strikes along the lines of the Chelyabinsk meteor, which hit Russia in February, are of the greatest concern for the time being, he said.
"If we could have detected the Chelyabinsk asteroid and had tools in place to quickly assess the impact scenario, an evacuation of the area would have prevented many injuries," Melosh said. "Much like we do for hurricanes, the best option is often to get people out of harm's way and prepare for the impact."
Melosh is currently working to refine an asteroid impacts effects calculator he developed so that it could be used in such situations. The calculator, "Impact: Earth!" estimates the damage that an asteroid strike would cause if it hit the Earth.