There are tens of thousands of asteroids with orbits that cross Earth’s path. Most pose little or no threat to the inhabitants of our planet, but occasionally, a large space rock will pass between the Earth and Moon or even enter the Earth’s atmosphere. Large impacts are rare, but everywhere we look in our solar system, we see craters and other evidence from past collisions with asteroids and other space debris that could have a global impact if Earth had been the target.

Spacecraft visiting asteroids have revealed a diverse population of these remnants from the formation of the solar system, differing in composition, mass and density, but how much do we really know about these denizens of deep space, and how can we protect ourselves and our planet from future encounters? Efforts are underway to better understand the risks posed by Near-Earth Objects and the options available to avoid a large-scale catastrophe. These include NASA's first planetary defense test mission, DART, which assesses the ability to shift an asteroid's orbit through kinetic impact.  

Bill Cloutier is a NASA Solar System Ambassador,  amateur astronomer, and founding member of the John J. McCarthy Observatory in New Milford, Connecticut. He has a life-long interest in astronomy, astrophotography, space exploration history, with a special interest in lunar imaging, and sharing those interests with the public.

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