Feeds

Xena moon's Gabrielle

More on the solar system's 10th planet

Security for virtualized datacentres

Astronomers at the WM Keck Observatory have identified a moon orbiting Xena, a body they argue is the 10th planet in our solar system. They have called the moon Gabrielle, after Xena's sidekick in the TV series Xena: Warrior Princess.

Regular readers may remember that Xena's (formally 2003 UB313) discovery reignited an old debate about what exactly ought to be classified as a planet. There is also some debate over who found the planet first, but we will not revisit that here because for astronomers, the important question has always been whether or not Xena has a moon.

Xena, the 10th planet, has a moon. Image: W.M. Keck Observatory

The California Institute of Technology's Michael Brown explains that although observations can show that Xena is physically larger than Pluto, without a companion body, it would be impossible to tell whether or not it is more massive.

"Finding a moon...allows us to precisely measure the mass of the planet. A more massive planet will pull on the moon tightly and it will circle the planet more quickly," he writes.

"A less massive planet will allow the moon to have a slow lazy orbit around the planet. We don't yet know the speed of the moon, but when we do we will suddenly have new insight into the size and even composition of the 10th planet."

The discovery could also shed new light on the history of the solar system. Several of the larger Kuiper belt objects, of which Xena is one, have moons, but how they acquired them is an open question.

The astronomical community has also yet to settle the question of whether Xena is a planet, and indeed, whether or not Pluto should be given that status. Many astronomers feel that Pluto ought more properly to be classed as a minor planet, or even just as a large Kuiper belt object.

Xena's discovery has prompted the International Astronomical Union to reconsider its definition of a planet. Currently it considers both Pluto and Xena to be trans-Neptunian objects, and says that until it has drawn up its new definition, that is what they will remain. ®

Security for virtualized datacentres

More from The Register

next story
Boffins say they've got Lithium batteries the wrong way around
Surprises at the nano-scale mean our ideas about how they charge could be all wrong
Thought that last dinosaur was BIG? This one's bloody ENORMOUS
Weighed several adult elephants, contend boffins
Europe prepares to INVADE comet: Rosetta landing site chosen
No word yet on whether backup site is labelled 'K'
City hidden beneath England's Stonehenge had HUMAN ABATTOIR. And a pub
Boozed-up ancients drank beer before tearing corpses apart
'Duck face' selfie in SPAAAACE: Rosetta's snap with bird comet
Probe prepares to make first landing on fast-moving rock
Archaeologists and robots on hunt for more Antikythera pieces
How much of the world's oldest computer can they find?
prev story

Whitepapers

Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.
Saudi Petroleum chooses Tegile storage solution
A storage solution that addresses company growth and performance for business-critical applications of caseware archive and search along with other key operational systems.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.
Providing a secure and efficient Helpdesk
A single remote control platform for user support is be key to providing an efficient helpdesk. Retain full control over the way in which screen and keystroke data is transmitted.