what
if a planet touched earth at all I am pretty sure it would not just "scrape the surface" under any number of circumstances
also, wtf? how in the hell would nobody have noticed an entire loving planet getting close enough to earth to collide with it?
it would have been nowhere near a "normal day" anywhere on earth
and, it would have been way too far away to get anywhere near earth if the planet had been "newly discovered"
In response to the last part, thats why its fiction, you can make things happen that are impossible otherwise.
being fiction and making no sense at all are two entirely different things