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New Discoveries In Pluto
Ongoing discoveries in the transneptunian
region keep rejuvenation the debate. In 2002,
50000 Quaoar was discovered, with a 1280 km diameter,
making it quite more than half the size of Pluto.
Another recent discovery, 90482 Orcus, is perhaps
even larger. In 2004 the discoverers of 90377
Sedna, an extremely distant object well beyond
the other known transneptunian objects, placed
an upper limit of 1800 km on its diameter, close
to Pluto's 2320 km.
Trans-Neptunian object called
2003 UB313 was announced in July 29, 2005,, which
on the basis of its magnitude and simple albedo
considerations is implicit to be larger than Pluto.
This caused its discoverers to call it as the
"10th planet" of the solar system, although
there is no accord so far on whether to call it
a planet, and others consider the new discovery
to be the strongest dispute however for demoting
Pluto to the status of a minor planet. 2003 UB313
could be the largest object yet discovered in
the solar system since Neptune in 1846. The last
remaining distinctive feature of Pluto is now
its large moon, Charon, and its atmosphere; these
characteristics may not, however, be unique to
Pluto: several other transneptunian objects (not
including Sedna) are known to have satellites;
and 2003 UB313's spectrum suggests that it has
a similar surface composition to Pluto, as well
as a moon discovered in September of 2005.
There is some chronological model for "demoting"
a "planet" in the light of consequent
discoveries. The first four asteroids (1 Ceres,
2 Pallas, 3 Juno and 4 Vesta) were considered
to be planets for several decades. Still,
in 1845, the first new asteroid in 38 years
was discovered, just one year before Neptune,
and soon every year brought more asteroid
discoveries. It was soon accepted that Ceres
and the others were just the most well-known
members of a populous asteroid belt, and although
asteroids are also known as "minor planets",
they are no longer considered "planets".
Some see in this a precedent for noting that
Pluto is just the most important member of
the Kuiper belt. |
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In contrast, it may very well
regardless of of future astronomical discoveries;
Pluto will stay grandfathered as a planet in much
the same way that Europe is considered a separate
continent for past reasons although geographically
it makes more sense, from first ideology, to consider
both Europe and Asia to encompass the single continent
of Eurasia.
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