Yes, it's an old idea. They attempted to explain it with the "Nemesis Theory". That is, that the sun had a companion star, as most stars do. And, periodically, every 26 million years or so, that companion would stir up the comets in the distant Ort Cloud, sending some comets in toward the inner solar system and into a collision course with earth. They still haven't found compelling evidence that the sun in fact has a companion.
Another potential explanation was the Carousal Theory, or something similar to that, which theorizes that the galaxy, as it orbits around the galactic center, "bobs" up and down like a horse on a merry-go-round, and that that stirs up the comets in the Ort Cloud. I think they've since ruled that one out.
What really riled up the comets in the Ort Clout was when their production was stopped by Mercury manufacturers.
Hope I have the right car company, but the old Comet was actually a very nice looking car.
Oort Cloud