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Pluto has lost its seven-decade status as the ninth and outermost planet of the solar system, the world's top astrononomical body has decided.
The decision was made at an assembly of the International Astronomical Union (IAU).
"The eight planets are Mercury, Earth, Venus, Mars, Jupiter, Saturn, Uranus and Neptune," said the IAU resolution, passed in a raised-hands vote after what, by the discreet standards of the astronomical community, was a stormy debate.
Pluto's status had been contested for many years by astronomers who said that its tiny size and highly eccentric orbit precluded it from joining the other acknowledged planets.
The call for an official definition of the word "planet" gained ground after the discovery of a distant object beyond Pluto's orbit called 2003 UB313, nicknamed Xena. It is slightly bigger than Pluto and thus could lay claim to being a planet.
Pluto was discovered on 18 February 1930 by US astronomer Clyde Tombaugh, who was then 24 years old.
Named after the god of the underworld in classical mythology, it orbits the Sun at an average distance of 5,906,380,000 kilometres (3,670,050,000 miles), taking 247.9 Earth years to complete a single orbit.
