It's difficult to keep a conspiracy under wraps because sooner or later, one of the conspirators will blow its cover, Oxford researchers said.
An Oxford study has examined how long alleged conspiracies could "survive" before being exposed - deliberately or unwittingly - to the public at large.
Dr David Grimes, researcher at Oxford University, devised an equation to express this, and then applied it to four famous collusions.
The equation developed by Dr Grimes, a post-doctoral physicist at Oxford, relied upon three factors: the number of conspirators involved, the amount of time that has passed, and the intrinsic probability of a conspiracy failing.
He then applied his equation to four famous conspiracy theories: The belief that the Moon landing was faked, the belief that climate change is a fraud, the belief that vaccines cause autism, and the belief that pharmaceutical companies have suppressed a cure for cancer.
In each case, the number of conspirators and the time before the conspiracy was revealed were over-estimated to ensure that the odds of a leak happening were a 'best case scenario' for the conspirators - around a four in one million chance of deliberate or accidental exposure.
He then looked at four alleged plots, estimating the maximum number of people required to be in on the conspiracy, in order to see how viable these conspiracies could be.
These include - the theory that the US moon landings were a hoax (411,000 people); that Climate Change is a fraud (405,000 people); that unsafe vaccinations are being covered up (22,000 people); that the cure for cancer is being suppressed by the world's leading pharmaceutical firms (714,000 people).
Using the equation, Grimes calculated that hoax moon landings would have been revealed in 3 years 8 months, a climate change fraud in 3 years 9 months, a vaccination conspiracy in 3 years 2 months, and a suppressed Cancer cure in 3 years 3 months.
In simple terms, any one of the four conspiracies would have been exposed long before now.
"It is common to dismiss conspiracy theories and their proponents out of hand but I wanted to take the opposite approach, to see how these conspiracies might be possible. To do that, I looked at the vital requirement for a viable conspiracy - secrecy," Grimes said.
"I hope that by showing how eye-wateringly unlikely some alleged conspiracies are, some people will reconsider their anti-science beliefs," Grimes said.
The findings were published in the journal PLOS ONE.
