In about six weeks a European space craft will attempt to land on a comet for the first time. A successful landing would be a startling work of science.
The lander will descend from the Rosetta satellite (which itself took a decade to arrive) to the comet '67P' via a 20km free fall. That is equivalent to dropping a 100kg washing machine from twice the cruising height of an airliner, and controlling it from half a billion kilometres away (via a 28-minute delay) to hit a spot 1km in diameter.
You might think, given the details involved, that truth would be stranger than fiction. But that's not enough for some people. Namely the people who think that the comet itself is an enormous alien space craft.
Let's look into that!
A conspiracy theory which is picking up steam on various websites and blogs Huffington Post news articles maintains (to a greater or lesser extent) that 67P is not a random comet hurtling through space, but the remnants of some ancient civilisation which has been sending radio waves out to Nasa for 20 years.
This video below contains the key points, summarised in just about explicable English, including a zoomed-in version of the above photo which appears to show (if you squint) a sort of radio dish-shaped thing on the surface.
So where does the theory itself come from?
In part, it's just echo chamber fodder for sites like UFO Sightings Daily, which do a good trade in treating each UFO rumour on the internet like it's (a) true and (b) so self evident so as to not really be worth investigating in any great detail.
There is also this comet, sent to various sites, which claims to be from an ESA official revealing the conspiracy:
Unfortunately, the conspiracy theory has more holes that the comet itself has craters.
For instance: if the comet is emitting radio waves, why has no one else been able to tune it? If there are UFOs inside, why haven't they been caught in any detail in any of the hundreds of high-resolution photographs taken by the comet? If the radio waves were picked up by NASA, why did they leave the space mission to investigate to the European Space Agency? And so on.
Needless to say, it's not true.
But when the news of the landing (good or ill) comes through at 4pm on 12 November, maybe just keep your ears open in case our alien masters choose to make their presence known through the most complicated, elaborate and risky means conceivable.