Comet Nearly Hit Earth? Not So Fast 84
Phil Plait ("The Bad Astronomer") writes with a skeptical take on the recent report that a comet may have narrowly missed earth. According to the linked post from Plait, "When a comet breaks up, it spreads out. Even when intact, the material surrounding a comet can be tens or even hundreds of thousands of kilometers across! Claiming that a comet broke apart, yet managed to constrain its pieces to volume of space less than a few thousand kilometers across strains credulity. Mind you, Bonilla claimed to have seen these objects over the course of two days. That means they would’ve been stretched out along a path that was a million km long at least, yet so narrow that only one observatory on Earth saw them transit the Sun. That is highly unlikely. Worse, the very fact that no one else saw anything makes this claim even less tenable."
Re:That's what I said! (sort of) (Score:4, Insightful)
If this comet was so close, so much so that no other observatory on earth was able to see it due to "parallax", how come not one of the 450 or so pieces impacted the earth? (There are no reports of Tunguska sized impacts).
While I agree with your skepticism, considering this was pre-radio era, and that we might have had some impacts on water and just didn't know it. The earth is over 2/3rds water, after all, so odds are always that a meteorite will hit water, not land. There is also the possibility that we were hit with many, many smaller meteorites (smaller than a Hyundai) over mainly water. Or the fact that comets are often made of water ice, so most of what hit the atmosphere either evaporated on the way down or shortly thereafter. If a chunk of water ice had hit the planet anywhere over 100 years ago, odds were certainly in the favor of it hitting either water or uninhabited land.
Yes, we need more evidence, but it does seem worth the time and effort for someone more knowledgeable than you and I to research a bit more. As for the question "Will Earth experience near misses?", the answer is an obvious "yes", since we also get major hits every 130 million years or so, so the idea that this did happen is at least plausible.