speaking of

used to introduce a remark about a topic recently alluded to:

Asteroid 2012 DA14 – Earth Flyby Reality Check

Graphic depicts the trajectory of asteroid 2012 DA14 on Feb 15, 2013. In this view, we are looking down from above Earth’s north pole. Image credit: NASA/JPL-Caltech 

Graphic depicts the trajectory of asteroid 2012 DA14 during its close approach, as seen edge-on to Earth’s equatorial plane. The graphic demonstrates why the asteroid is invisible to northern hemisphere observers until just before close approach: it is approaching from “underneath” our planet. On the other hand, after close approach it will be favorably placed for observers in the northern hemisphere. Image credit: NASA/JPL-Caltech 

"According to NASA scientists, the trajectory of the Russia meteor was significantly different than the trajectory of the asteroid 2012 DA14, making it a completely unrelated object. Information is still being collected about the Russia meteor and analysis is preliminary at this point. In videos of the meteor, it is seen to pass from left to right in front of the rising sun, which means it was traveling from north to south. Asteroid DA14’s trajectory is in the opposite direction, from south to north."

(Source: nasa.gov)