> Thanks for this. Obviously there was a hole in my education. But as you
> noted, the small size of these things means very little dust will be thrown
> into the atmosphere and thus very they are not likely to be a threat to
> civilizations.
Was the comment about "hole" deliberate or accidental? With respect to the threat
to civilisation, so far so good...... Sooner or later though there will be a big
one.
God Bless
Jonathan