Earth (sometimes) has a 2nd moon

...is the theory being floated by Cornell Astrophysicists

From the Gizmodo synopsis (which I will shorten too):

In a research paper called "The population of natural Earth satellites", astronomers say that Earth has a second moon at any given time. While these moons are small, the scientific implications of this discovery are phenomenal. 

From the Technology Review article linked below:

image via http://www.inrumor.com/

Back in 2006, the Catalina Sky Survey in Arizona noticed that a mysterious body had begun orbiting the Earth. This object had a spectrum that was remarkably similar to the titanium white paint used on Saturn V rocket stages and, indeed, a number of rocket stages are known to orbit the Sun close to Earth.
But this was not an object of ours. Instead, 2006 RH120, as it became known, turned out to be a tiny asteroid just a few metres across--a natural satellite like the Moon. It was captured by Earth's gravity in September 2006 and orbited us until June 2007 when it wandered off into the Solar System in search of a more interesting neighbour.
2006 RH120 was the first reliably documented example of a temporary moon.


-

 COOL!

Source -> http://gizmodo.com/5869840/ via Cornell & https://www.technologyreview.com/blog/arxiv/27425/

Earlier links about the Moon -> http://www.dannyfinnegan.com/2011/11/moon_19.html & http://www.dannyfinnegan.com/2011/08/was-our-moon-result-of-2-smaller-moons.html