Pluto Regains Its Title As Largest Object In Its Neighborhood

sciencehabit writes "In 2005 astronomers discovered Pluto's biggest neighborhood rival: Eris, which they claimed definitely surpassed Pluto in size. Now, as astronomers report an analysis of methane gas in Pluto's atmosphere suggests that Pluto is about 2368 kilometers across, in which case it's larger than Eris and thus the champ of the Edgeworth-Kuiper belt, which boasts more than a thousand known objects revolving around the sun beyond Neptune's orbit."

Comments

Re:And when Eris' atmosphere is measured...

[cunniff]

From TFA:

Eris is just 2326 kilometers across—possibly smaller than Pluto, whose diameter is somewhere between 2300 and 2400 kilometers. The uncertainty arises because Pluto, unlike Eris, has air that complicates the interpretation of observational data.

Ah, the Planet Pluto

[ackthpt]

I remember it well -- before the anti Pluto is a Planet conspiracy. Good to see it's getting some recognition, rather than more damnation.

Re:Ah, the Planet Pluto

[Anonymous Coward]

1) With the discovery of the other clutter that could be considered within Pluto's orbit, it means that any consistent definition of a planet would either not include Pluto, would include Ceres, or would not include Mercury. After some bickering and debate, the guys who run the telescopes decided to start calling Pluto a dwarf planet, and toss Ceres, Eris, and a couple dozen other big rocks into that bucket.

2) 'Kilo' is the metric prefix for 1000, not 1024. There already was confusion between an OS's kilobyte and a storage manufacturer's kilobyte. Kibibyte is a lame hack to try to instill some semblance of binary order in a scenario where marketing will trump all such efforts.

I now return you to your regularly scheduled ranting.

Re:Ah, the Planet Pluto

[Shalaska]

First off, Pluto was originally called a planet back before all of the objects that are in the same orbit as Pluto were spotted, thus under the definition that a planet must clear its orbit fails. Second if kilobytes are so clear and unambiguous, why do hard drive manufacturers consider them 1000 bytes when all computer scientists and programmers consider them 1024? http://www.glyphtech.com/suppo...

Re:Ah, the Planet Pluto

[ChromaticDragon]

If you believe there's some pedantic reason to keep Pluto as a planet, I have to ask whether you hold the same views regarding Ceres.

Ceres was "a planet for both the common and technical definitions for quite some time".

The circumstances surrounding demotion of Ceres and Pluto are rather similar. The timeframe either of the two were considered planets is also similar.

Now, what I find more interesting BOTH for this issue of Eris and Pluto and the argument over Planet classification is to look at MASS instead of diameter:

http://en.wikipedia.org/wiki/L...
http://en.wikipedia.org/wiki/F...

Look at this chart of bodies in our Solar System ranked by mass in a logarithmic chart. The eight planets unambiguously rank as the largest bodies. Eris still is more massive than Pluto. And all the dwarf planets are outranked by several moons.

Yes definitions are arbitrary. But the eight planets stand apart. It does make sense to align definitions to match such. In any case, the definitions OUGHT to be consistent. What criteria other than inertia of publications would you prefer that keeps Pluto IN yet leaves Ceres OUT?

Re:Ah, the Planet Pluto

[cheesybagel]

Because the definition of what is a planet changed. For no good reason at all.