The size of a comet changes depending on how close it is to the sun. As a comet gets closer to the sun, the ices on the surface of its nucleus vaporize and form a cloud called a coma around...

The comet's size is further extended by an enormous hydrogen cloud that surrounds the coma.

Comet structures are diverse and very dynamic, but they all develop a surrounding cloud of diffuse material, called a coma, that usually grows in size and brightness as the comet approaches the Sun.

"Spitzer was crucial in pinning down the comet's size, and the combination of Spitzer and Hubble was vital to learning its reflectivity and rotation rate," said Michael A'Hearn of the University...

I report here simulations of the tidal breakup of the parent comet, which I assume ... By comparing the size, number and distribution of the stimulated fragments with observations of Shoemaker–Levy 9,

"Spitzer was crucial in pinning down the comet's size, and the combination of Spitzer and Hubble was vital to learning its reflectivity and rotation rate," said Michael A'Hearn of the University...

This video will show you how to determine the best screen size for your living room space. ... This video will show you how to determine the best screen size for your living room space. ... Your Comet

And estimating its size. (diameter of Comet Hale-Bopp may be four times large - The brightness of Hale-Bopp in the latest observations with the Hubbl : Encyclopedia.com ... He cautions, however,

It was a cataclysmic event that underscored the enormous scale and terrible randomness of space: a comet, a planet and a spectacular collision that left Jupiter nursing a dark bruise roughly the...

Dan, The real issue here is not of the size of the object, but of the energy it releases in the collision.