Patrick Moore invented the 1976 Jovian-Plutonian gravitational effect hoax broadcast on BBC Radio 2.
The prank aired on April 1, 1976, when English astronomer and broadcaster Patrick Moore announced that Jupiter and Pluto would pass into a special alignment at 9:47 a.m. He claimed that the planets’ combined gravitational influence would briefly reduce Earth’s gravity. Listeners were invited to jump at the precise moment to experience a floating sensation.
The claim was scientifically absurd: a planetary conjunction could not suddenly cancel or noticeably weaken Earth’s gravity in the way described. Nevertheless, the broadcast sounded convincing enough that the BBC received hundreds of calls from people claiming they had felt the effect. One caller even said that she and eleven friends had floated from their chairs and orbited around a room.
The hoax also reflects its era. In 1976, Pluto was still widely classified as the Solar System’s ninth planet; the International Astronomical Union reclassified it as a dwarf planet in 2006. James Burke was another prominent BBC science presenter, but Moore was the prank’s inventor.