By Harold Reitsema -
Humankind lives in a cosmic shooting gallery. For evidence of that, we need look no further than the events of 15 February 2013. On that day, a medium-size asteroid was set to pass some 28,000 kilometers from Earth, unusually close and well within the orbits of geosynchronous satellites. Dubbed 2012 DA14, the rock was first spotted the previous year. Since then, astronomers had been eagerly anticipating the opportunity to take a closer look and measure such vitals as size, shape, and composition.
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Sentinel is a private telescope satellite that will look for potential objects that could destroy our planet
