My Very Educated Mother, Cathy, Just Served Us Nine Purple-Clad Xylophones!?
Alright, I'd like to comment on how ridiculous this debate is getting. The IAU (International Astonomical Union) is trying to get a universal consensus on planetary status. And while I applaud their effort, I think they are moving in the wrong direction. I guess you could link me in with the rest of the world's "Pluto-haters" because I don't think Pluto should be considered a planet. Here is the IAU's new definition of what a planet is as of today and according to FL Today:
I decided to do a little more investigation on the definition, because I fear that FL Today has missed something. According to the IAU News website, they have defined a planet to be:
This whole thing is just getting out of control. The IAU wants to add 3 new "planets" to our solar system. The list moving outward from the sun would be as follows: Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Charon and 2003 UB313.
What you say?! Ceres?! Since when did they sneak a planet in between Mars and Jupiter without me knowing!? Ah, this is where the "planet definition" comes
into play. According to the new definition. 800km is the cutoff, and the largest asteroid on the main belt, Ceres, is between 909-975km (the discrepancy is due to it being not perfectly round...a 7% non-roundness in fact!) That's right, now they want to start calling asteroids planets! FYI, that picture shows Ceres (green dot on the left) compared to the size of our moon! ARRRGG!
Ok, let's back up for a moment and delve into a little history on everything. Back in the 1800, Ceres was discovered and thought to be a planet for awhile. It was even in the textbooks. Then we got better instruments and discovered many more objects just like it orbiting in a ring between Mars and Jupiter. Ceres was immediately demoted as one of the largest of "asteroids" in this belt, and everyone was happy. Why we didn't learn from this and do the same to Pluto, I have no idea? Pluto was discovered serendipitously while looking for something much larger. There were unexplained perturbations in Neptune's orbit, so astronomers assumed there must be another "Neptune" disturbing the orbit. So they went looking for one. Years later, they found a fuzzy object that moved against the background stars, wiped their hands clean and said they found "Planet X" without taking any measurements, or doing any research on what they really found. As time went on, our instruments got better and we learned so much more about Pluto.
1. Neptune's orbit wasn't being perturbed by anything, we just miscalculated.
2. Pluto is extremely small...and more recently has be calculated even smaller because we finally were able to resolve it's moon from the combined diameter of the two.
3. Pluto's orbit is extremely eccentric (0.25).
4. Pluto's orbit has an incredibly high inclination (17%) (LOOK------->)
5. Pluto's surface is very icy, like a comet's surface. In fact, if you were to push Pluto towards the sun, it would develop a coma and a tail just like all other comets do.
6. There are many other objects, just like Pluto, that have been discovered in Pluto's region of the solar system (Kuiper Belt). In fact, the object 2003 UB313 (nicknamed Xena for now) was discovered further from the sun than Pluto and is larger than Pluto!
Does number 6 sound familiar? It was the exact reason that Ceres was dropped to asteroid status. So why isn't Pluto being dropped to Kuiper Belt Object (KBO) status?
And why isn't Pluto's inclination and eccentricity being taken into consideration? According to the standard model of how stars form, there is a "planetary disc" that forms roughly in the plane of the spinning star's equator. Material accretes together in this plane and forms planets. Pluto is way outside of this plane! And then there's the comet-like eccentricity of Pluto's orbit. In fact, short period comets are thought to originate in the Kuiper Belt!
Well, someone must've been thinking like me because the IAU has developed a working definition of a pluton.
Planet: any round object larger than 800 kilometers (nearly 500 miles) in diameter that orbits the sun and has a mass roughly one-12,000th that of Earth.That's it? That's what you boneheads have come up with?! If this were the case, then our friggin moon would be a planet!
I decided to do a little more investigation on the definition, because I fear that FL Today has missed something. According to the IAU News website, they have defined a planet to be:
A planet is a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet.Ok, so that helps a little by eliminating our moon, and all other moons from being deemed a "planet". But hold on, Charon, Pluto's moon, is up for planetary status. Why? According to Wikipedia, because "the barycenter of the Pluto-Charon system lies above Pluto's surface".
This whole thing is just getting out of control. The IAU wants to add 3 new "planets" to our solar system. The list moving outward from the sun would be as follows: Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Charon and 2003 UB313.
What you say?! Ceres?! Since when did they sneak a planet in between Mars and Jupiter without me knowing!? Ah, this is where the "planet definition" comes
into play. According to the new definition. 800km is the cutoff, and the largest asteroid on the main belt, Ceres, is between 909-975km (the discrepancy is due to it being not perfectly round...a 7% non-roundness in fact!) That's right, now they want to start calling asteroids planets! FYI, that picture shows Ceres (green dot on the left) compared to the size of our moon! ARRRGG!Ok, let's back up for a moment and delve into a little history on everything. Back in the 1800, Ceres was discovered and thought to be a planet for awhile. It was even in the textbooks. Then we got better instruments and discovered many more objects just like it orbiting in a ring between Mars and Jupiter. Ceres was immediately demoted as one of the largest of "asteroids" in this belt, and everyone was happy. Why we didn't learn from this and do the same to Pluto, I have no idea? Pluto was discovered serendipitously while looking for something much larger. There were unexplained perturbations in Neptune's orbit, so astronomers assumed there must be another "Neptune" disturbing the orbit. So they went looking for one. Years later, they found a fuzzy object that moved against the background stars, wiped their hands clean and said they found "Planet X" without taking any measurements, or doing any research on what they really found. As time went on, our instruments got better and we learned so much more about Pluto.
1. Neptune's orbit wasn't being perturbed by anything, we just miscalculated.
2. Pluto is extremely small...and more recently has be calculated even smaller because we finally were able to resolve it's moon from the combined diameter of the two.

3. Pluto's orbit is extremely eccentric (0.25).
4. Pluto's orbit has an incredibly high inclination (17%) (LOOK------->)
5. Pluto's surface is very icy, like a comet's surface. In fact, if you were to push Pluto towards the sun, it would develop a coma and a tail just like all other comets do.
6. There are many other objects, just like Pluto, that have been discovered in Pluto's region of the solar system (Kuiper Belt). In fact, the object 2003 UB313 (nicknamed Xena for now) was discovered further from the sun than Pluto and is larger than Pluto!
Does number 6 sound familiar? It was the exact reason that Ceres was dropped to asteroid status. So why isn't Pluto being dropped to Kuiper Belt Object (KBO) status?
And why isn't Pluto's inclination and eccentricity being taken into consideration? According to the standard model of how stars form, there is a "planetary disc" that forms roughly in the plane of the spinning star's equator. Material accretes together in this plane and forms planets. Pluto is way outside of this plane! And then there's the comet-like eccentricity of Pluto's orbit. In fact, short period comets are thought to originate in the Kuiper Belt!
Well, someone must've been thinking like me because the IAU has developed a working definition of a pluton.
The IAU draft Resolution also defines a new category of planet for official use: "pluton". Plutons are distinguished from classical planets in that they reside in orbits around the Sun that take longer than 200 years to complete (i.e. they orbit beyond Neptune). Plutons typically have orbits that are highly tilted with respect to the classical planets (technically referred to as a large orbital inclination). Plutons also typically have orbits that are far from being perfectly circular (technically referred to as having a large orbital eccentricity). All of these distinguishing characteristics for plutons are scientifically interesting in that they suggest a different origin from theAlright. Finally a ray of hope. So let's label Pluto, Charon, and Xena plutons, keep Ceres as an asteroid, and call it a day, huh? The IAU officially votes August 24th! Do the right thing guys!
classical planets.


3 Comments:
At 12:48 PM,
Ibid said…
I guess everyone is calling it Xena so I should, too. I thought they'd decided on Sedna, but then all the newspapers started using Xena. I asked the people at The Register why they made the change and they didn't even know they had until they checked the archives.
I'd think that Ceres would be the planet that should have been where the asteroid belt is but failed. Torn apart by the gravitational confict between Sol and Jupiter I guess. Still, it's too big for rubble, clearly part of Sol's accretion disk... I don't wanna call it a Pluton. Can we keep calling it a planetoid?
If Pluto didn't have those moons I'd have no problem calling it a comet. But just as my mind stuck on the name Sedna and refuses to let go it doesn't want to lose Pluto either.
>"barycenter"
Stop. You're getting me all turned on here.
At 9:35 PM,
Rene' said…
Ceres cannot be a pluton because it does not reside in the Kuiper Belt...so yes, it should still be called a planetoid, or asteroid or whatever.
And moons, shmoons for Pluto. There are a lot of Kuiper Belt objects floating around out there...two or more of them are bound to be close enough to get gravitationally locked, don't you think? I bet if we looked at the main asteroid belt we would see tons of binary asteroid systems.
At 8:08 AM,
Ibid said…
New rule:
"the object must be the dominant body in its orbital area."
Awwww. I liked having a binary planet.
Post a Comment
<< Home