[FoRK] KBO update -- this one about the size of Pluto, and much further out

Joseph S. Barrera III joe at barrera.org
Sun Mar 14 18:54:32 PST 2004


"The importance of Sedna is that it is the first such world discovered
in its normal orbit. Other similar though smaller worlds, like Quaoar
and Varuna, originated in the [Kuiper Belt] but have since been
perturbed into different orbits."

- Joe

Astronomers discover 'new planet'
By Dr David Whitehouse
BBC News Online science editor

*Astronomers have discovered a new world circling the Sun farther away 
than other planets.*

Found in an outer Solar System survey by the recently launched Spitzer
Space Telescope, it has been called Sedna after the Inuit goddess of the
ocean.

Observations show it is about 2,000 km across, and it may even be larger
than Pluto which is 2,250 km across.

The Hubble Space Telescope has also seen it. Details will be announced
by the US space agency Nasa on Monday.

*World of rock and ice*

Sedna is the largest object found circling the Sun since the discovery
of Pluto in 1930. Its size is uncertain.

One astronomer told BBC News Online that it may even be larger than
Pluto itself.

It was found during the course of a survey led by Dr Michael Brown of
the California Institute of Technology. Scientists are only midway
through this three-year project.

   KUIPER BELT OBJECTS
   Icy planetary bodies that orbit beyond Neptune in the distant region
        of the Solar System
   More than 400 such objects are currently known
   They are believed to be remnants of the formation of the Solar
        System and among the most primitive objects available for study

Preliminary calculations suggest that it is 10bn kilometres from Earth
in a region of space known as the Kuiper Belt (KB).

The KB contains hundreds of known objects and astronomers believe there
are many more awaiting discovery. Most are small worlds of rock and ice
but some, like Sedna, could be as large as or larger than Pluto.

The importance of Sedna is that it is the first such world discovered in
its normal orbit. Other similar though smaller worlds, like Quaoar and
Varuna, originated in the KB but have since been perturbed into
different orbits.

*Planet debate*

Following the objects discovery astronomers at the Tenagra Observatory
in Arizona were asked to provide positional information so that an orbit
could be determined for Sedna.

The new discovery will reignite the debate about what is a planet.

One group of astronomers believe that Pluto is not a true planet but
merely one of the largest of a vast number of minor objects in the outer
Solar System.

The alternative standpoint is that Pluto is a planet and those who
believe that will have to classify Sedna as the tenth planet.

Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/hi/science/nature/3511678.stm

Published: 2004/03/15 01:12:07 GMT

© BBC MMIV



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