Earth's 'mini moon' may have been a chunk of our actual moon

Earth is parting company with an asteroid that's been tagging along as a “mini moon” for the past two months. The harmless space rock will peel away on Monday, overcome by the stronger tug of the sun's gravity. But it will stick around the neighborhood and pass within 1 million miles of Earth in January. Then it will zoom farther into the solar system and will not return until 2055. Discovered in August, the asteroid will be observed by NASA as it zips by next year. Scientists suspect it may be a boulder that was blasted off the moon during an asteroid impact.