[Dragon Star]

They characterized the first results as no less than shocking. The astronomers expected to find mostly interstellar grains — tiny, crystalline and noncrystalline specks that stuck together to form the cometary material. They found interstellar grains, but found much larger particles that are made of complex minerals, many of which had been shocked and melted in the distant past, and stuck together like brecciated rocks.

Comets are mostly icy dirtballs, and they are presumed to have formed out in the very coldest part of the solar system. If this is so, how could they contain rock that was obviously superheated? This major puzzle now looms over planetary scientists.

http://www.astronomy.com/asy/default.aspx?c=a&id=4801

Now that's just odd. Perhaps the Comet was struck by a recent explosion and the small particles were embedded within the Comet?