Source picture : http://spaceref.com/comets/comet-c2012-s1-is-on-its-way-toward-the-inner-solar-system.html
Astronomers worldwide are becoming very excited about an approaching sun-grazing comet by the name of ISON . With a bit of luck , this comet could become a very bright comet , visible by the naked eye , visible during day time . Some even speculate it will have a brightness of a full moon ! Yeah !!
The tail of this comet is expected to be formed beginning of December
The NASA video ( in the link below ) is explaining what a sun-grazing comet is .
Here are some very good in-depth articles on this comet Ison :
Update Nov 29 , 2013 : not much hope for ISON to become a ” Comet of the Year ”
Update : https://alleswatis.wordpress.com/2013/12/05/update-comet-ison-as-seen-by-satellite-cor2-a/