Tuesday, November 14, 2006

Xena Warrior Dwarf?

Perhaps you've heard that Pluto has been demoted.

No, I don't mean Mickey's dog or Donald Duck's pet or Goofy's pooch. (Although I have always wondered why a mouse or a duck or another dog would have a dog as a pet).
I mean Pluto, the ninth planet in our solar system has been downgraded to dwarf planet status.
I don't like that particularly. I grew up with Pluto. In my science projects I've made little clay or styrofoam Pluto dangling out there farthest from the sun, and now they want to change these basic facts. Nope don't like it. I don't like the change in the pronounciation of Uranus either but, I wont go there.
But, I love astronomy and know that the more technology enhances observation of the heavens the more things will change.

Back a couple years ago a new planetary sphere was discovered by Professor Michael
Brown of the California Institute of Technology, and this new rock was at that time thought to possibly be our tenth planet or replace Pluto as our ninth planet.

This new sphere was catalogued by the International Astronomical Union (IAU) as 2003 UB313, but Mike Brown unofficially named it Xena, after the popular TV Heroine, Xena Warrior Princess.

Is it a planet? Does it have a moon? Mike brown said.
"Having a moon is just inherently cool. And it is something that most self-respecting planets have, so it's good to see that this one does too".

Being the cool guy he is, Mike named (again unofficially) the little moon Gabrielle, after Xena's TV sidekick. There was fierce campaigning to the IAU by astronomy fans, Xena fans, and Mike Brown and his science pals, to officially keep those names.

Xena and Gabrielle facts:

Xena and Gabrielle live beyond Pluto in a band known as the Kupier Belt, a region that is home to asteriods, comets and other space rocks.

Xena is about 2100 miles in diamter.

Xena's orbit is highly eccentric, 45 degrees above the other planets.

Her orbit is also elliptical, zooming in as close as 5.6 billion kilometers and out as far as 14.5 billion kilometers away.
FYI - Earth orbits rather consistantly at 150 million kilometers from the sun.
It takes Xena 560 years to make one orbit around the sun. It takes Pluto 250 years.

Gabrielle is about 250 kilometers in diameter.
Gabrielle cirles close to Xena, completing one trip around, every 14 days.

The discovery of large spheres like Xena have caused the IAU to redefine the definition of planet. Their redefinition determined that only the rocky worlds of the inner solar system and the gas giants of the outer system will hereafter be designated as planets.
Therefore, both Xena and Pluto were both demoted to dwarf planets, leaving our solar system with 8 planets. How odd that sounds.

The Name
Well this August, the IAU officially named celestial body #2003 UB313, Eris.
In Greek mythology, Eris is the goddess of warfare and strife.
Gabrielle is now officially Dysnomia. She is Eris' daughter and the demon spirit of lawlessness. (No pun intended, Lucy).

So in a world, where you can pay to name a star after cousin Fred, these old fogies (in attitude) chose that violent pair rather than two contemporary fictional ancient Greek heroines.
Well, It's too bad, Xena and Gabrielle were meant to be together. It was fun for a while to see them get this honor.

Check out, Mike Brown's charming non-scientific personal account of all of this, Requiem for Xena, it's worth a read.

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