This was on the cards for a long time. Now there are 8 planets
instead of 9 or 12 (proposed earlier). How would the astrologers
react to this after humans (whose fate is supposedly controlled
by planetary motions) change the status of planets themselves.
It might be interesting to see how long it takes for textbooks
to change.

--
http://news.bbc.co.uk/2/hi/science/nature/5282440.stm
--
Pluto loses status as a planet

Pluto's status has been contested for many years.
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, Earth, Venus, Mars,
Jupiter, Saturn, Uranus and Neptune," said the IAU
resolution, which was passed following a week of
stormy debate.

The initial proposal put before the IAU to raise the
number of planets in the Solar System to 12 - adding
the asteroid Ceres, Pluto's "moon" Charon and the
distant object known as 2003 UB313 - met with
opposition.

Robin Catchpole, of the Institute of Astronomy in
Cambridge, UK, told the BBC News website: "My own
personal opinion was to leave things as they were; I
met Clyde Tombaugh and thought how nice it was to
shake hands with someone who had discovered
a planet.

"But since the IAU brought out the proposal for new
planets I had been against it - it was going to be
very confusing. The best of the alternatives was to
leave the major planets as they are and then demote
Pluto. So I think this is a far superior situation."

Louis Friedman, executive director of the Planetary
Society in California, US, commented: "The
classification doesn't matter. Pluto - and all Solar
System objects - are mysterious and exciting new
worlds that need to be explored and better understood."

Dwarf planet

Amid dramatic scenes which saw astronomers
waving yellow ballot papers in the air, the IAU meeting
voted in criteria that define the exact nature of a "planet".

They agreed that to qualify, 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".

Pluto's status has been contested for many years
as it is further away and considerably smaller than
the eight other "traditional" planets in our Solar System.

Its orbit around the Sun is also highly inclined to the
plane of those big planets.

In addition, since the early 1990s, astronomers have
found several objects of comparable size to Pluto in an
outer region of the Solar System called the Kuiper Belt.

Some astronomers have long argued that Pluto
belongs with this population of small, icy worlds.

Allowances were once made for Pluto on account of
its size. At just 2,360km (1,467 miles) across, Pluto is
smaller even than some moons in the Solar System.
But until recently, it was still the biggest known object
in the Kuiper Belt.

That changed with the discovery of 2003 UB313 by
Professor Mike Brown and colleagues at the California
Institute of Technology (Caltech). After being measured
with the Hubble Space Telescope, it was shown to be
some 3,000km (1,864 miles) in diameter, making
it larger than Pluto.

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.

-- Vinayak

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