Conspiracy theories often rely on arguments that take the following form: “Because there is a mystery with no ready explanation, this means that things are not as they seem; there is a hidden reality, which I can explain.”

Perhaps the most well known supposed mystery surrounds the Moon landing in 1969. The American flag that the astronauts planted appeared to be rippling in the wind – but there’s no wind on the Moon, so how could this have happened? Conspiracy theorists used this mystery as “evidence” that the entire event must have been staged in a studio on Earth.

Instead of an elaborate charade, there is a very simple explanation for why the flag appeared to flutter in the breeze. NASA didn’t want the flag to hang limply, so it constructed a telescoping, horizontal bar to which the top of the flag was attached. When the astronauts deployed the flag, they could not get this bar to extend fully. This caused a kink in the flag, which made it appear to be rippling in the wind. Later crews left the flag like this because they liked the way it looked. Conspiracy theorists took this mystery, which had a very simple, but not well known, explanation and presented it as “proof” that the moon landing never took place.

This technique of pointing to supposed mysteries can be surprisingly effective. It may be that our minds are especially attuned to look for anomalies, perhaps as a sign of danger. This may have been very useful for survival in the wild, but is not very useful for understanding our complex, largely man-made world. Most apparent mysteries can be explained if one does the necessary research.