Download Solar System has 8 planets instead of 9 — IAU official vote

Solar System has 8 planets instead of 9 — IAU official vote
17176 Views · August 24 · Filed under nature, world record
Pluto loses its status as a planet, declared officially by International Astronomical Union (IAU)
today on Aug 24, 2006 after several years of debate since its discovery in 1930.
Definition of a Planet
1. must be in orbit around a star while not itself being a star
2. must be large enough in mass for its self-gravity to overcome rigid body forces so that it
assumes a… nearly round shape
3. has cleared the neighbourhood around its orbit
With this definition, Pluto was automatically disqualified because its oblong orbit overlaps with
Neptune’s.
Some Facts about Pluto
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A “demoted” planet
Named after underworld god
Average of 5.9bn km to Sun
Orbits Sun every 248 years
Diameter of 2,360km
Has at least three moons
Rotates every 6.8 days
Gravity about 6% of Earth’s
Surface temperature -233C
Nasa probe visits in 2015
Why the name “Pluto”? Read more…
Astronomers meeting in the Czech capital have voted to strip Pluto of its
status as a planet.
About 2,500 experts were in Prague for the International Astronomical Union’s
(IAU) general assembly.
The scientists rejected a proposal that would have retained Pluto as a planet
and brought three other objects into the cosmic club.
Pluto has been considered a planet since its discovery in 1930 by the American
Clyde Tombaugh.
The ninth planet will now effectively be airbrushed out of school and university
textbooks.
“The eight planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus
and Neptune,” said the IAU resolution, which was passed following a week of
stormy debate.
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They agreed that to qualify as a planet, a celestial body must be in orbit around
a star while not itself being a star. It also must be large enough in mass “for its
self-gravity to overcome rigid body forces so that it assumes a… nearly round
shape, and has cleared the neighbourhood around its orbit.”
Pluto was automatically disqualified because its oblong orbit overlaps with
Neptune’s.
It will now join a new category of “dwarf planets”.
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Named after the god of the underworld in Roman mythology, Pluto orbits the
Sun at an average distance of 5.9 billion kilometres (3.7 billion miles) taking
247.9 Earth years to complete a single circuit of the Sun.
An unmanned US spacecraft, New Horizons, is due to fly by Pluto and the
Kuiper Belt in 2015.
Read more on: bbc.co.uk