Black and Dead comets

February 11th NASA newsflash (see full story at www.jpl.nasa.gov/news/ ) … a new satellite, launched in December to track NEOs has discovered it’s first comet. It will make an extensive survey of comets, asteroids and NEOs and routinely scan the sky with infra red imaging technology that can not only pick up comets ejecting material but also dark comets and dead comets whose whereabouts is unknown and a potential threat to life on the surface of the earth. These latter comets, or pieces of comet, are on unknown orbits and trajectories by reason they cannot at the moment be seen. The level of threat is therefore an unknown.