“Fine” is probably something of an exaggeration. There’s more to it than just a lack of food and a “blast winter.” One of the major killers, aside from the massive fireball and superheated shock wave that basically leveled everything for a thousand miles, was believed to be the fallback of huge amounts of ejecta, which heated the upper atmosphere like a giant broiler with the expected result, including massive firestorms worldwide. If that’s “fine” then count me out.
OK, how long would we have from it reaching our outer atmosphere, and it contacting the ground? Seconds? What sort of effects on the atmosphere could we expect to see, before lights out?
But most of it would recoalesce pretty quickly, even the vapor. Most of the atmosphere would probably be blown away, though. And the hydrosphere, too. You’d end up with a nice smooth sphere of molten metal and rock.
Upthread someone suggested that Superman could do it. Sorry, no go. Superman trying to move the Earth would be like moving a large blob of Jell-O with the point of an icepick. All you do is make holes in the gellatin/Earth. Yeah, I know he’s done it in the comic books, but you can’t believe everything you read in comic books. They make stuff up, you know…
The 2004 earthquake and tsunami slowed Earth’s rotation by some fraction of a second.