Pluto fight not over....

[Dr Mordrid]

http://www.newscientistspace.com/article/dn9890-astronomers-plot-to-overturn-planet-definition.html

Astronomers plot to overturn planet definition

* 20:42 31 August 2006
* NewScientist.com news service
* David Shiga

Pluto's status could shift yet again, as astronomers are mounting a grassroots campaign to readdress the definition of a planet.

More than 300 researchers have signed a statement denouncing the recently adopted definition that relegates Pluto to "dwarf planet" status, and some are planning a conference in 2007 to hash out an alternative definition.

Last week, scientists at a meeting of the International Astronomical Union (IAU) in Prague, Czech Republic, voted to approve a new planet definition that recognises only eight planets.

But many astronomers find fault with the new definition's criteria – which state a planet must have cleared out the neighbourhood around its orbit. There have also been complaints about the small number of scientists allowed to vote on the issue.
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[RedRed]

Have we (Earth) cleared out our orbit? I notice a big ball of rock glowing in the sky some evenings

I suppose we are getting semantic here- Current theory is that the Earth/Moon is a binary formed from a 'billiard ball' reaction to a massive whack on the earth some time ago.....

[lowlifecat]

couple theories about that.

1 is that the moon was the satelite of whatever smacked the earth that got left behind

2 race of superiour beings(feline) live on this smacking planet and geneticly engineered us monkeys

3 earth lost 40% of it's initial mass from the smack

i don't know anymore, it's been a long night

[Gurm]

By "cleared out its orbit" they simply mean that there's nothing ELSE hanging out in orbit that isn't now orbiting around the planet. So if there were a planet in whose orbit there were asteroids that didn't orbit the planet... then under this new definition it's not a planet but a really big asteroid.

The problem with Pluto is that it HAS cleared out its orbit, but its orbit is at an angle. If it weren't at an angle, odds are it would have become a moon of Neptune long ago.

[Dr Mordrid]

As I asked before; who has the crack concession at the IAU?

Hopefully with more people voting they'll recind the abomination they passed this time. A perfect example of a poorly thought out rule if ever there was one.

[Jon P. Inghram]

As I asked before; who has the crack concession at the IAU?

Hopefully with more people voting they'll recind the abomination they passed this time. A perfect example of a poorly thought out rule if ever there was one.

Yeah, lets not apply logic to anything, that might confuse and scare some people.

[KRSESQ]

By "cleared out its orbit" they simply mean that there's nothing ELSE hanging out in orbit that isn't now orbiting around the planet.

What about Lagrange points? Has anyone actually measured what is in Earth's leading and trailing Lagrange points?

Kevin

[Dr Mordrid]

IMO half the IAU members wouldn't know a Lagrange point from the end of their ....

[Nowhere]

Gurm, no - apparently they mean what was happening during the creation of the planet; not about objects that ended in its vicinity much later. Also, none of planets of our system shares its region with other objects of significant influence - as a matter of fact, what's left is governed by the planets gravity.
And as such Pluto hasn't cleared its orbit - it's totally governed by Neptune.

KRSESQ, the same thing applies to Earth, which is a governor in its region of system. Not only when it comes to the Moon...there are bodies orbiting Sun that are locked in one way or another to Earth:

http://en.wikipedia.org/wiki/3753_Cruithne

http://en.wikipedia.org/wiki/2002_AA29

http://en.wikipedia.org/wiki/2003_YN107

And Doc...ohh, cut the crap of rebelling against them just for principles. Probably removing Pluto is better option...and after all, it was discovered purely by chance, expected to be something much bigger (which later proved to be error in observations/calculations of Neptun's orbit) (BTW, Pluto would develop features of a comet if placed closer to the Sun). Sure, the current definition isn't perfect (is that even possible?), surelly will be replaced by something more optimal in the future...but it serves it's purpose - removes Pluto from the list of planets. And while that may alienate large number of people from astronomers - you'll either do that, or add to the list of planets dozens of new objects that will be discovered in the future (already one of them is larger than Pluto...).

Technically, they could come up with much more weird descriptions - after all, for example, we're practically living in a some form of binary system: barycenter of Sun and Jupiter lies between the two, not inside of Sun (so...it's Sun, Jupiter and debris...and why the Jupiter should be included in the same class as debris?). What they come up with at least uses limits set by nature to decide (of course you still have to choose the criteria)