Among one of the most ridiculous-sounding fears about the supposed 2012 Mayan apocalypse is the idea that the Earth might be hit by a rogue planet.
Asteroids - sure, they're flying all over the place. But planets? They're pretty hard to lose.
Well, not that hard it turns out.
According to research released in 2011, but causing concern for the gullible and easily worried this week ahead of the 21 December end of the world 'deadline', we may be missing a planet.
Research into the early history of our Solar System indicates there may once have been at least one or more extra 'giant' planets orbiting the Sun which have since disappeared.
Researchers at the Southwest Research Institute in Colorado ran more than 6,000 computer simulations of the formation of the Solar System, and found surprising results.
In short, our solar system makes a lot more sense if it once had more planets.
According to the study, those models which began with four giant planets - as we have now - had only a 2.5% chance of leading to a system which looks like our own.
In that case, the violence of the early solar system would have been too great to end up with our current structure without difficulty, the researchers said.
Models which looked at systems starting with five giant planets resulted in solar systems like us more than 10 times as often.
The extra planet - possibly an "ice giant" like Neptune or Uranus - would have been scattered away from the Sun after about 600 million years.
Similar 'lost' worlds have been found before, wandering alone through space.
So how likely is it that Earth could be hit by one?
Not. At. All... Yet.
Nasa explained recently that if such a planet were heading for Earth, we'd know about it for at least a decade.
It said:
"Nibiru and other stories about wayward planets are an Internet hoax. There is no factual basis for these claims. If Nibiru or Planet X were real and headed for an encounter with the Earth in 2012, astronomers would have been tracking it for at least the past decade, and it would be visible by now to the naked eye.
"Obviously, it does not exist. Eris is real, but it is a dwarf planet similar to Pluto that will remain in the outer solar system; the closest it can come to Earth is about 4 billion miles."
So there you go. No need to panic. It'll probably be aliens instead. Now go watch the world end online.