One of the most common theories lays the blame with chemicals in the environment, which mimic the sex hormone, oestrogen.

It goes on to admit that "many of the more common theories" refuse to stand up to scrutiny.

A weather balloon is one of the more common theories used to explain the UFO crash near Roswell, New Mexico and Area 51.

Despite the lack of conclusions, Schapiro addressed some of the most common theories that have circulated about what triggered last week's 20-minute market roller coaster.