why most of the heavenly bodies are spherical in shape?

Question

anonymous · Answer

Due to gravity, in the begining small particles concentrate around a common gravity center. As increase in size, the heat (a different topic...) and the gravity itself, fashion the body (planets, stars,etc) in spherical shapes.  
Debido a la gravedad, al comienzo de la formacion del cuerpo, las particulas se concentran alrededor de un centro de gravedad comun. A medida que crece en tamaño, el calor (otro tema aparte...) y la gravedad, modelan al cuerpo con forma esperica. (planetas, estrellas)

anonymous · Answer

just to support AstroTandil's point, this 'shaping' happens during the initial conditions, when the body is still a lump of hot gas cloud, contracting due to it own gravitational attraction.