Title text:
Paleontologists have long worried that the dinosaurs blasted into space 66 million years ago will one day complete their orbits and fall back down.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3265/
Based purely on the thumbnail and title, I thought this was going to be a joke about a tiny clone of Earth being the asteroid and wondered how the heck that would work as set-up and punchline.
And even though that's not actually what's going on in the image, I still kind of want someone to make the wrong interpretation work.