Instead of channeling their energies into unknown world beyond, bringing the frontier to our doorstep, the IAU has resorted to cheap thrills by wailing and screaming to get their way, playing with the definitions. Nothing has changed actually since the Planet Pluto still orbiting out there.
We have a new Horizon probe on route. By administratively removing Pluto, now they can claim to have visited all the planets in our solar system. So much energy channeled into a useless endeavour...sad....truly sad...
Welcome to the world of Science... I wonder what is the big deal and I think this is very common in the Scientific world. If your "theory or definitions" can't stand the test of time and fact, sorry it had to go...
Anyway, I think this is a good thing that they give a definitions of what is a planet... even in the end Pluto didn't fit the definitions and had to be discarded. So what?? Now we clearly know what is a planet and what is not!! We can now answer this question when someone ask us what is a planet.
Have a nice day.
Yang Weixing "The universe is composed mainly of hydrogen and ignorance."
Remember the contest to rename the 'Black Hole'? In the end, the name still stays. It's like wasting money to come up with a new name for the Budget Terminal - and we all know the result of that contest!
[80% Steve, 20% Alfred] ------- Probability of Clear Skies = (Age of newest equipment in days) / [(Number of observers) * (Total Aperture of all telescopes present in mm)]
hmm what does the part on "clearing its neighbourhood around the orbit" means?
I think it's mean it had to be the biggest "object" around it's orbit... too bad Pluto orbit cross the obrit of Neptune.
there was a claim that due to trojan asteroids sharing Jupiter's orbit, Jupiter wont qualify for it..
But jupiter is the biggest "object" around it orbit... just ask those trojan asteroids to go near Jupiter and we'll see what does "clearing its neighbourhood around the orbit" really means... ha ha ha
Have a nice day.
Yang Weixing "The universe is composed mainly of hydrogen and ignorance."
weedee wrote:hmm what does the part on "clearing its neighbourhood around the orbit" means?
there was a claim that due to trojan asteroids sharing Jupiter's orbit, Jupiter wont qualify for it..
and does it mean that it has a roche limit wide enough to significantly crumble a good area around its path?
I was curious about what "has cleared the neighbourhood around its orbit" meant as well, and it turns that it was not clearly defined by the IAU! But, to me, it does for the most part make sense:
From Wikipedia: "clearing the neighbourhood"
Clearing the neighbourhood" is an informal description of part of the process of planet formation.
The phrase refers to an orbiting body "sweeping out" its orbital region over time, by gravitationally interacting with smaller bodies nearby. Over many orbital cycles, a large body will tend to cause small bodies either to accrete with it, or to be disturbed to another orbit. As a consequence it does not then share its orbital region with other bodies of significant size, except for its own satellites, or those collected later under its gravitational influence (such as Trojan asteroids).
[...]
The concept has been used by the IAU in its August 2006 redefinition of the term "planet" as one of the criteria differentiating a planet from a dwarf planet; a planet is a body with sufficient mass to largely clear its orbit of other objects. The IAU determined that Pluto will now be considered a dwarf planet because it has not cleared the neighborhood of its orbit (vis-à-vis Neptune and Kuiper Belt Objects such as the Plutinos).
The concept of clearing its neighbourhood does not really refer to its roche limit (Definition: Roche limit: The smallest distance from a planet or other body at which purely gravitational forces can hold together a satellite or secondary body of the same mean density as the primary. At less than this distance the tidal forces of the larger object would break up the smaller object.). Most objects will be deflected or captured by a planets significantly larger gravity without coming near its roche limit.
Last edited by chrisyeo on Sat Aug 26, 2006 7:11 pm, edited 1 time in total.
but then , if its called a dwarf planet, doesnt it make jupiter and saturn giant planets?
Yes... size is relative and to me (and I believe to most people) they are the Giant Planets because they are very big:
1) Jupiter is 2.5 times more massive than all the other planets combined.
It is 318 times more massive than Earth, with a diameter of 11 times of Earth, and a volume of 1300 times of Earth... even the Great Red Spot can put 2 to 3 Earth in it.
2) Saturn is the second massive planet. It is 95 times more massive than Earth, with a diameter of 9 times of Earth, and a volume of 763 times of Earth.
Together with Uranus and Neptune, they are the Gas Giants of the solar system!
Have a nice day.
Yang Weixing "The universe is composed mainly of hydrogen and ignorance."
i think they have to demote Pluto because pluto is the start of many more minor planets beyond. So if Pluto stays as a planet, then other small rocks discovered out there have to be classified as a planet as well. Then we have 1001 planets in the end... that would be too confusing, haha
"The universe is composed mainly of hydrogen and ignorance." 
