  A recent paper by Siraj & Loeb (2021) entitled "Breakup of a long-period
comet as the origin of the dinosaur extinction" attempts to revive the
perennial debate about what type of body hit the Earth 66 million years ago,
triggering the end-Cretaceous extinction. Here we critique the paper and assess
the evidence it presents. To consider a comet more likely than an asteroid
requires extreme assumptions about how comets fragment, conflation of
carbonaceous chondrites with specific types of carbonaceous chondrites, and a
blind eye to the evidence of the iridium layer.
