Also, wouldn't there be obvious traces outside N.A.?
And what connection is implied by "a supernova" and "lunar meteorites" and a comet hitting the earth? Maybe he should restrict his language to math, instead of trying to speak English.
Or, was this a Babelfish translation from English to Manglish?
Right side image: The Mark of the Cosmic Turtle!
Or, maybe WE'RE SAVED!
Last time I saw that critter, rocket flames were coming out of the leg holes of his shell, and he was leaving Earth for Mars. Took him long enough to get there.
"Calling Monster Island; come in Monster Island; Godzirra, protect us! Over!"
“Isn’t “1,000 KPH” (625 MPH or ~0.25 KPS) pretty slow for a cometary inpact?”
You’re right. The Earth itself is barrelling around the Sun at 66,705 MPH; and Earth-incoming meteorites, comets, etc. can be expected to enter Earth’s space at incredible velocities ... especially in head-on situations.
One for-instance is Chesapeake Bay; it was apparently carved out by a comet strike about 36 million years ago.