Planet X Larger Than Pluto?

nova_planitia writes "The Minor Planet mailing list is buzzing with the discovery by an amateur astronomer of a 17th magnitude object 51 astronomical units from the Sun, tentatively designated 2003 EL61. For those not versed in astronomical lingo, this is an object several times brighter than Pluto even though it is 25% farther out from the Sun (the orbit vizualised by JPL). This means that barring a strangely reflective surface, this object is larger than Pluto, possibly Mars-sized! The debate whether Pluto is a planet is likely to get rekindled by this discovery."

Comments

Pluto is a planet?

[Quasar1999]

Yes, because we defined it as such. Right or wrong, we've defined it as a planet, therefore it is a planet. Stop debating and arguing over the status of the hunk of rock. It's not like if we define it as something else it will change or cease to physically exist. We are simply categorizing it. We could call it a comet, it fits into that category too.

Re:Pluto is a planet?

[Anonym1ty]

Here are My Definitions:

Star: Any massive gaseous body emitting more energy due to nuclear fusion then by thermal radiation alone.

Planet: Any body orbiting a star which is roughly spherical due to self-gravitation. (by this definition our solar system has 13 (14 now?) planets including Charon, Ceres, Sedna and Quaoar)

Planetoid: Any body not orbiting a star which is roughly spherical due to self-gravitation. There is conjecture on this one. It once was just a synonym for asteroid, however now many call Ceres, Sedna and Quaoar planitoids or even minor planets, but I don't since they all meet my definition of a planet.

Planetesimal: Any celestial object that does not have suffecient mass to form into a spherical shape. All asteroids and comets are planetesimals.

Protoplanet: Any body in a solar nebula which is roughly spherical due to self-gravitation and does not produce energy by nuclear fusion.

Moon: An object which is roughly spherical due to self-gravitation which orbits a planet. By this definition Phobos and Demos are not moons.

Satellite: An object whose mass is not sufficent to form into a spherical shape which orbits a planet.

Double-Planet: Two Planets of comparable mass orbiting one another in a system orbiting a star, who are both tidally coupled so as to always show the same face to each other in a system with a center of gravity that is not within either body. The center of gravity of the Earth/Moon system is about 2900 km or about 75% of the radius from the center of the Earth. Also, the Earth doesn't always show the same face to the moon. The Earth/Moon system is NOT a double-planet. The Pluto/Charon system is a double planet as they always show the same face to each other and the center of gravity of the Pluto/Charon system does not lay within either body.

Re:RTFA before you post an article to slashdot!

[richdun]

Actually, TFA mentions that astronomers discovered Sedna in 2004, and since this is 2005, this is a separate discovery.

from TFA: "The same team that found Sedna have designated it [the new discovery] K40506A after it was picked up by the Gemini telescope and one of the twin Keck telescopes in Hawaii."

Amateur astronomer?

[fruity_pebbles]

The TFA mentions two teams of scientists who found the object independently of each other. It doesn't say anything about discovery by an amateur astronomer.

Doesn't add up

[exp(pi*sqrt(163))]

The published magnitude of Pluto is around 13-14. This thing is 25% further from the Sun (and Earth too) away but several times 'brighter' due to being more reflective and larger. That means it ought to appear brighter in the sky than Pluto. But it's reported as magnitude 17, which is quite a bit dimmer.

Re:Broken Link, Naming Contest.

[saintp]

I'm afraid that iPlanet is already taken. And as the other responder -- the one who posts on so many phpBB boards that he's forgotten HTML -- pointed out, the my- prefix is pretty passe. It's almost as bad as "cyberplanet."

Anyhow, shouldn't the new planet be named after a Roman god or goddess? I mean, let's choose a naming scheme and stick with it, people.

Re:Never noticed it before?

[mbone]

I wouldn't expect any new planets to be found from gravitational perturbations, at least for a long while. (JPL's orbit is from the direct observations, not predicted from perturbations.)

The orbital periods are long, and generally it takes at least one orbit of observations to say much about whether you have unwanted perturbations. Pluto has an orbital period of 248 years, and about a century of observations, so it's a bit too soon to say much about perturbations yet. Come back in a century.

Plus, Pluto and Neptune are in a 3:2 resonance, and there is a lot of other junk out there also in the 3:2 resonance with Neptune. And it doesn't help much that all Pluto observations are from Earth, and it's pretty far away. But it's the short duration of observations that kills detectablility from orbit perturbations.

Re:New Scientist Coverage

[Idealius]

where's the spin!?

there's no angle!

good luck next time :)

Re:Name for it:

[Anonymous Coward]

or womanned rather

Re:Depends on the orbit

[Fiver-]

An enormous rock with a name from the Underwold? The obvious choice is Sisyphus.

Re:Planet X Larger Than Pluto?

[Anonymous Coward]

You don't considering a new planet in the solar system newsworthy!? How many have you discovered this week?

Re:Pluto is not a planet

[Peyna]

Ok, I'll say it, you can say it with me. Ready, Pluto is not a planet. It is a Kuiper belt object. http://en.wikipedia.org/wiki/Kuiper_belt Yes it's got a moon, yes it's pretty big for a KBO but it's not a proper planet. If Pluto is a planet then so is Ceres http://en.wikipedia.org/wiki/1_Ceres and Juno http://en.wikipedia.org/wiki/(3)_Juno They're even round too.


You left out the most important thing:

It doesn't matter at all whether it is a planet or not.

Besides, there is no consensus on what the definition of a "planet" should be, especially considering new discoveries that are occuring. Just as continues to be with classification of organisms, we will likely see a continuing evolution of classification of large objects in the universe.

Classifications assist our understanding of how things are related. But you can't argue that a particular object is or isn't under one particular classification until that classification actually has a solid definition (and Webster's doesn't count.)

Re:Pioneer

[truckaxle]

The Pioneer anomoly is a unaccounted for force in the direction of the Sun and results the slowing down of the probes. If this new object was some massive unkown body it would be if anything applying a force out from the Sun. Also the probes are in different quadrants and would expect to see different effect.

Re:Broken Link, Naming Contest.

[andy_shepard]

Something non-Greek/Roman at last.

We want them to stick with classical names. Otherwise, the PC brigade steps in and we get stupid names like Quaoar.

Re:Name for it:

[xihr]

There's already an Apollo asteroid named Bacchus.