Cometary structure

Comets were proposed to be 'dirty snowballs,' primarily composed of ice and dust that vaporizes near the Sun, forming a coma and tail. This model became widely accepted in understanding cometary composition.
 Fred Lawrence Whipple United States 1949 Cometary structure

Comets were proposed to be 'dirty snowballs,' primarily composed of ice and dust that vaporizes near the Sun, forming a coma and tail. This model became widely accepted in understanding cometary composition.