Jovian-Plutonian gravitational effect

The Jovian–Plutonian gravitational effect, a hoax phenomenon stated to cause a noticeable short-term reduction in gravity

Gravitation

Gravitation, or gravity, is a natural phenomenon by which physical bodies attract with a force proportional to their mass. Gravitation is most familiar as the agent that gives weight to objects with mass and causes them to fall to the ground when dropped...

on Earth

Earth

Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

, was an invention for April Fools' Day

April Fools' Day

April Fools' Day is celebrated in different countries around the world on April 1 every year. Sometimes referred to as All Fools' Day, April 1 is not a national holiday, but is widely recognized and celebrated as a day when many people play all kinds of jokes and foolishness...

by the English

English people

The English are a nation and ethnic group native to England, who speak English. The English identity is of early mediaeval origin, when they were known in Old English as the Anglecynn. England is now a country of the United Kingdom, and the majority of English people in England are British Citizens...

astronomer

Astronomer

An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...

Patrick Moore

Sir Patrick Alfred Caldwell-Moore, CBE, FRS, FRAS is a British amateur astronomer who has attained prominent status in astronomy as a writer, researcher, radio commentator and television presenter of the subject, and who is credited as having done more than any other person to raise the profile of...

broadcast on BBC Radio 2

BBC Radio 2

BBC Radio 2 is one of the BBC's national radio stations and the most popular station in the United Kingdom. Much of its daytime playlist-based programming is best described as Adult Contemporary or AOR, although the station is also noted for its specialist broadcasting of other musical genres...

on 1 April 1976.

Background

Patrick Alfred Caldwell-Moore

Patrick Moore

(born 4 March 1923) was and still is the doyen of British television astronomers, boasting a long career in public service broadcasting

Public broadcasting

Public broadcasting includes radio, television and other electronic media outlets whose primary mission is public service. Public broadcasters receive funding from diverse sources including license fees, individual contributions, public financing and commercial financing.Public broadcasting may be...

, a quick-fire manner of speech, and a number of eccentric habits, including the wearing of a monocle

Monocle

A monocle is a type of corrective lens used to correct or enhance the vision in only one eye. It consists of a circular lens, generally with a wire ring around the circumference that can be attached to a string. The other end of the string is then connected to the wearer's clothing to avoid losing...

. A wartime navigator in the Royal Air Force

Royal Air Force

The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...

's Bomber Command

RAF Bomber Command

RAF Bomber Command controlled the RAF's bomber forces from 1936 to 1968. During World War II the command destroyed a significant proportion of Nazi Germany's industries and many German cities, and in the 1960s stood at the peak of its postwar military power with the V bombers and a supplemental...

, he was elected a Fellow of the Royal Astronomical Society

Royal Astronomical Society

The Royal Astronomical Society is a learned society that began as the Astronomical Society of London in 1820 to support astronomical research . It became the Royal Astronomical Society in 1831 on receiving its Royal Charter from William IV...

in 1945 and has presented BBC Television

BBC Television

BBC Television is a service of the British Broadcasting Corporation. The corporation, which has operated in the United Kingdom under the terms of a Royal Charter since 1927, has produced television programmes from its own studios since 1932, although the start of its regular service of television...

's The Sky at Night
The Sky at Night
The Sky at Night is a monthly documentary television programme on astronomy produced by the BBC. The show has had the same permanent presenter, Sir Patrick Moore, from its first airing on 24 April 1957, making it the longest-running programme with the same presenter in television history.The...

programme since 1957. He was appointed an Officer of the Order of the British Empire

Order of the British Empire

The Most Excellent Order of the British Empire is an order of chivalry established on 4 June 1917 by George V of the United Kingdom. The Order comprises five classes in civil and military divisions...

in 1968. Above all, Moore has a high level of public recognition in the United Kingdom as a respected astronomer.

The planet

Planet

A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...

Jupiter

Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...

is two and a half times as massive as all of the other planets in the Solar System

Solar System

The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...

combined.

Pluto

Pluto

Pluto, formal designation 134340 Pluto, is the second-most-massive known dwarf planet in the Solar System and the tenth-most-massive body observed directly orbiting the Sun...

is so small and so remote from the Sun

Sun

The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

and the Earth

Earth

Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

that it was not identified as a planet until 1930. In 2006, the International Astronomical Union

International Astronomical Union

The International Astronomical Union IAU is a collection of professional astronomers, at the Ph.D. level and beyond, active in professional research and education in astronomy...

reclassified it as a dwarf planet

Dwarf planet

A dwarf planet, as defined by the International Astronomical Union , is a celestial body orbiting the Sun that is massive enough to be spherical as a result of its own gravity but has not cleared its neighboring region of planetesimals and is not a satellite...

, deciding that it belongs to a belt of many similar small objects.

Events of April 1976

On April 1

April Fools' Day

, 1976, Moore stated to radio listeners that an astronomical event would take place at 9:47 a.m. that day, a conjunction of Jupiter and Pluto, which was expected to have an effect observable everywhere. As Pluto passed behind Jupiter, it would briefly cause a powerful combination of the two planets' gravitation

Gravitation

which would noticeably decrease gravity on Earth

Earth

Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

. If listeners were to jump into the air at that exact moment, they would find they felt a floating sensation.

Soon after 9:47 on that morning, the BBC

BBC

The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...

began to receive hundreds of telephone calls from people reporting they had observed the decrease in gravity. One woman who called in even stated that she and eleven friends had been sitting and had been "wafted from their chairs and orbited gently around the room".

Aftermath

The story was quickly revealed as an April Fools' Day

April Fools' Day

hoax

Hoax

A hoax is a deliberately fabricated falsehood made to masquerade as truth. It is distinguishable from errors in observation or judgment, or rumors, urban legends, pseudosciences or April Fools' Day events that are passed along in good faith by believers or as jokes.-Definition:The British...

. Martin Wainwright later wrote in The Guardian
The Guardian
The Guardian, formerly known as The Manchester Guardian , is a British national daily newspaper in the Berliner format...

In 1980, Moore collaborated with Clyde Tombaugh

Clyde Tombaugh

Clyde William Tombaugh was an American astronomer. Although he is best known for discovering the dwarf planet Pluto in 1930, the first object to be discovered in what would later be identified as the Kuiper Belt, Tombaugh also discovered many asteroids; he also called for serious scientific...

, the man who had discovered Pluto in 1930, to publish a new book about the dwarf planet.

Background

Events of April 1976

Aftermath

See also