Dirty iceballs

There are days I wonder why I even read Nature. Gives you just way too much to worry about.

Anyway, in the one more thing to worry about file, we now have this:

The dark comets would present a major challenge to astronomers searching the skies for objects that might collide with the Earth. "They're so black you can't see the damn things," says Napier. "These things will just come out of the dark and hit you with no warning. It looks as if we're dealing with a substantial impact hazard that people haven't clicked into yet."

...and I have to say, that's just wrong. Everyone who's been to grade school knows it ain't nice to pack rocks into your snowballs... let alone tar.