- It is already known that the body was discovered in
2003 by the designation 2003 ULB313.
- Why is it now stated it was spotted in "January",
inferring that the discovery occurs in 2005?
- Even more interestingly, why was the discovery kept
- Note the following statement: "Xena was first
spotted in January. Since then scientists have been checking its
position and size before making their announcement. They had hoped to
hold back for longer, but a secure website containing details of the
discovery was recently hacked and the hacker threatened to release the
The Little Rock Causing Galactic
It's been named after the warrior princess. But
the only fighting involved with Xena is between scientists, bitterly
divided as to whether she is our latest planet, or just a jumped-up
By Robin McKie
The Observer - UK
- Astronomers have found a new world orbiting the Sun.
The giant lump of rock and ice is larger than the planet Pluto and is
now the farthest known object in the solar system.
- The discovery was announced by US scientists
yesterday and the object has unofficially been named Xena, after the
TV series starring Lucy Lawless. 'We have always wanted to name
something Xena,' said Michael Brown, a member of the team that made
the discovery using telescopes at the Palomar Observatory, outside San
- Preliminary observations suggest Xena - officially
known as 2003 UB313 - is an extremely strange world. It is currently 9
billion miles away from the Sun, roughly 100 times more distant than
the Earth, and is now about three times more remote than Pluto. At its
present distance, the Sun will appear so small in the sky it will
almost be indistinguishable from other stars.
- Xena will also be incredibly cold. Its surface
temperature is likely to be only a few degrees above absolute zero,
while a year there - the time Xena takes to make one passage round the
Sun on its highly elliptical orbit - will be the equivalent of 560
- Despite its distance, the little world is also
proving to be highly controversial. Astronomers cannot agree whether
it is a planet or just a jumped-up asteroid. Its discoverers are
claiming Xena is the 10th planet. Other astronomers say it is just
another of the Sun's minor planets. There are thousands of minor
planets in the solar system, but only nine fully fledged major
- The last full planet to be discovered - in 1930 by
US astronomer Clyde Tombaugh - was Pluto. But recently some
astronomers have campaigned to have Pluto downgraded to 'minor planet'
status. It is so small - its diameter is a mere 2,200 kilometres -
that it is unworthy of the status of full planet, it was argued. This
bid was finally rejected after heated scientific debate.
- But now the discovery of Xena, which is only
slightly bigger than Pluto, will re-ignite that row. Both Pluto and
Xena are components of the Kuiper Belt, which is made up of thousands
of small asteroid-like objects, many mere lumps of rock, that sweep
the outermost depths of the solar system. As members of the Kuiper
Belt, neither Pluto nor Xena should be rated full-fledged planets, it
- The trouble for astronomers is that they do not have
an exact definition of a planet. Many say that, if Pluto had been
discovered today, it would not have been called a proper planet. In
1999 one group from the US Minor Planet Centre proposed that Pluto be
given a new joint classification so that it would keep its position
among the major planets, but also be given a designation as a minor
planet. The centre dropped the proposal after outcry from those who
saw it as a demotion.
- Gareth Williams of the centre said he still
supported dual status for Pluto, but did not think Xena should be
added to the registry of major planets. It should be left as as a
minor planet 'permanently', he said.
- But Mark Sykes, director of the Planetary Sciences
Institute in Tucson, Arizona, disagreed. It should be classed as a
full planet, he said. 'The kinds of questions we would ask about this
object [Xena] would be planet-like questions,' he said. For example,
does it have an atmosphere and what sort of geological processes
generated its apparently bright surface?
- This view was backed by the leader of the team that
discovered Xena. 'It is definitely bigger than Pluto, and I would say
it counts out as the 10th planet,' said Brown.
- Xena was first spotted in January. Since then
scientists have been checking its position and size before making
- They had hoped to hold back for longer, but a secure
website containing details of the discovery was recently hacked and
the hacker threatened to release the information.
- For Brown, the discovery is particularly satisfying.
Five and a half years ago, he bet fellow astronomer Sabine Airieau
five bottles of good champagne that he would find a Kuiper Belt object
larger than Pluto by the end of last year. In December, having failed,
he bought the champagne to send to her. Then 2003 UB313 was spotted on
- 'I lost the bet by eight days,' Brown said. 'But she
graciously decided she would let that window slide and I would win the
bet. That means I get to drink 10 bottles of good champagne. And I
think I will.'
Astronomers Detect '10th
By Dr David Whitehouse
BBC news website
- The new planet has a highly inclined orbit
- Astronomers in the United States have announced the
discovery of the 10th planet to orbit our Sun. The largest object
found in our Solar System since Neptune was discovered in 1846, it was
first seen in 2003 but has only now been confirmed as a planet.
- Designated 2003 UB313, it is about 3,000km across, a
world of rock and ice and somewhat larger than Pluto.
- Scientists say it is three times as far away as
Pluto, in an orbit at an angle to the orbits of the other
- Astronomers think that at some point in its history,
Neptune likely flung it into its highly-inclined 44-degree
- It is currently 97 Earth-Sun distances away - more
than twice Pluto's average distance from the Sun. Bigger than
- Its discoverers are Michael Brown of Caltech, Chad
Trujillo of the Gemini Observatory in Hawaii, and David Rabinowitz of
- David Rabinowitz told the BBC News website: "It has
been a remarkable day and a remarkable year. 2003 UB313 is probably
larger than Pluto. It is fainter than Pluto, but three times farther
- "Brought to the same distance from the Sun as Pluto,
it would be brighter. So today, the world knows that Pluto is not
unique. There are other Plutos, just farther out in the Solar System
where they are a little harder to find."
- It was picked up using the Samuel Oschin Telescope
at Palomar Observatory and the 8m Gemini North telescope on Mauna
- Slow Mover
- Chad Trujillo told the BBC News website: "I feel
extremely lucky to be part of a discovery as exciting as this. It's
not every day that you find something Pluto-sized or larger!"
- "The spectra that we took at the Gemini Observatory
are particularly interesting because it shows that the surface of 2003
UB313 is very similar to that of Pluto."
- The object was first observed on 21 October 2003,
but the team did not see it move in the sky until looking at the same
area 15 months later on 8 January 2005.
- The researchers say they tried looking for it with
the Spitzer Space Telescope, which is sensitive to heat radiation, but
failed to detect it.
- This gives them an upper limit of its size of 3,000
km, they say. The lower limit still makes it larger than Pluto.
- The discovery of 2003 UB313 comes just after the
announcement of the finding of 2003 EL61, which appears to be a little
smaller than Pluto.