Pure bull sh-t. A 62 mile diameter ice ball would have had most its mass when it hit the earth. This would be a global extinction event. Yes, the outer layers could fracture and explode. Most of that iceball would have made it to earth. THIS DID NOT HAPPEN.
cpdiii, you have a point but only because the paper was sorely misreported by Universe Today. From the very first sentence the actual paper maintains that we encountered a 100km comet that had been disintegrating for millennia before we crossed into a particularly lumpy and dangerous portion of the existing debris stream. The pre-existing fragments, large and small, impacted earth and exploded in the atmosphere. As you say, a 62 mile or 100km diameter object would hit the ground and ruin the earth completely before ever disintegrating in the atmosphere. As a (non-credentialed;) co-author of the papers, I have written to Universe and asked they correct this mistake. The same miscommunication on this point has dogged us for years. See the actual papers here on my blog, the Cosmic Tusk, and enjoy the incredible evidence behind our claims: https://cosmictusk.com/9483-2/
George A. Howard, Comet Research Group