This is only a Test: Asteroid tracking network observes close approach
Today, 12 October 2017, a small asteroid designated 2012 TC4 will safely pass by Earth at a distance of approximately 26,000 miles (42,000 kilometers). This is a little over one tenth the distance to the Moon and just above the orbital altitude of communications satellites. This encounter with TC4 is being used by asteroid trackers around the world to test their ability to operate as a coordinated international asteroid warning network.
Source: Homeland Security News