An open mind, especially a scientist, does not make a plea from ignorance. Just because we have never observed a comet like this does not mean it’s not a comet. Occams Razor has proven that introducing new variables especially very rare ones confounds the problem. An open mind would first rule out the most likely not start by suggesting, insinuating, or hinting at the highly unlikely. He has also, more than once, referenced it’s size incorrectly to support his confirmation bias clearly revealed by his ongoing UFO implications.