The fireballs seen in the sky of Chelyab insk this morning of Feb 15; such fireballs caused the injury of about 1000 of people because of the breaking of the glass of windows in addition to a wave of panic among people.
Almost such object is a comet and its pieces: the comet is attracted to the cold regions of the earth and the planets like Siberia, Alaska, and the north of Canada

http://quran-ayat.com/universe/new_page_3.htm#Comets