Killing asteroids before they kill us

摘要

The Siding Spring comet narrowly missed Mars in October 2014, just 22 months after the comet with an icy nucleus 400 to 700 meters in diameter was discoverd by an Australian scientist. If scientists discover a comet or asteroid destined to strike Earth on such short notice, there "is not a hell of a lot we can do about it at the moment," said Joseph Nuth, senior scientist for primitive bodies at NASA Goddard Spaceflight Center in Greenbelt, Maryland.