Sudbury Impact basin caused by a comet

Comets are becoming more complex the more we get to know them. And now Canada/Sudbury Ontario claims one hit just 1,849.5 million years ago, just circa 100km from where I am "astronomer in residence" for the past 4 years. I wipe the sweat from my brow!Sudbury impact basin

"The findings settle ..." - well, they do not. And science does not work quite that way - rather in a sentence
above: "... was likely formed by an enormous comet  ... suggested ... " is a little better.

We should also bear in mind that while Philae and Rosetta will relay to us much more detail about comet 67P Churyumov-Gerasimenko than we had previously known, it is detail about ONE comet and we have much to learn about how this fits into the general picture of our solar system. We know that there is much variety in composition among comets and even in the same comet - spatially, comet Hartley, or temporarily, comet Hale-Bopp.

                                                                   Comet Hartley:

 

Comet Hale-Bopp:

(The rise and fall of production of the various molecules is not constant  nor parallel.)