Sedna
 

So, Avian. What's the deal with Sedna?

"Sedna" (an unofficial name) is the largest object found so far outside Pluto. It's location is about 13 billion (thousand million for you Brits) kilometers away. This puts it outside the Kuiper Belt, a collection of icy rocks that goes out to around 50 AU or so. But it's also inside the inner boundary of the Oort Cloud, a theoretical sphere home to trillions of cometary bodies that's supposed to extend about halfway to the next star. Sedna has a huge, ellipical orbit around the sun. It's distance to the sun ranges from 11 billion km to 150 billion km. It takes 12,000 years to orbit the sun!

It's very large. They don't know the exact size yet, but it's smaller than Pluto - about half the size of our moon - somewhere between 1,200 to 1,700 km (Pluto is about 2400 km).

It's the largest object discovered since Pluto, which was discovered by Clyde Tombaugh in 1930.

It was discovered by a team looking for large objects in the outer part of the solar system. They are the same team that discovered "Quaoar" a few years ago (1,300 km across, and much closer).

Is it a planet? That topic is sure to be debated! Many scientists are holding Pluto as the standard minimum size for a planet - anything under would be a minor planet. But that's certainly arbitrary. The search continues!

Avian

it's educational!
 

How many other stations give you science lessons along with your prog rock?

:D

I forgot to mention that an AU is an Astronomical Unit, based on the average distance between the Sun and Earth - about 150 million kilometers (93 million miles).

Avian

and I thought...
 

Sedna was a Swedish prog band.

Or "Andes" spelled backwards?

I guess Sedna is an Inuit goddess that lives under the ice or something - probably got the name from the same source!

If I discover a minor planet, I'm going to name it Mel.

Avian

I always thought Bob would be a great name for some non-descript ice ball hurtling through space, but what do I know?

Hey, are we still playing StarDate or am I just not listening to the station enough?

Tommy

I don't care what scientists believe, it's an object with an independant orbit around the sun (doesn't orbit around other object so it's not a satelite), it's not an asteroid, so despite the size it's a planet, a very small one but still a planet.

Iván

Haley's Comet orbits the sun, as does Hale-Bopp (or whatever it's called) - not planets...

Sedna
 

Sedna is the Inuit goddess of the oceans but it seems strange that they chose this name rather than another Roman or Greek diety. I would have liked them to use the name Bacchus (Roman god of wine and drinking) but then again I would!!!!

If I discover a minor planet I'd call it Eric. Well we have Eric the fish (he is an 'allibut), Eric the cat and Eric the half a bee so why not Eric the minor planet?

don't forget
 

Eric the Fruit Bat!

An Halibut!


I've always been partial to Bob. It's a palindrome, and as such it's always fun to say! (plus, full of lucrative markting ideas as Bob, the littlest planet)

The palindrome of bolton would be notlob.....it don't work.
 

You want a palindrome? I'll point you to a palindrome!!!!!

Is this fun to say? :D

http://www.neuralintegrator.com/palindrome

my son
 

loves palindromes. He checked out a book once with short ones, but have funny pictures.

This one, while not repeating, is very non-sensical. Therefore, is it really useable?

It is funny, though!

And he spelled repetitive wrong in the introduction!

Am I taking this too seriously?:)

Only on AM can we go from celestial bodies to palindromes (although there are some celestial bodies that would be fun to go forwards and backward on) says he in his best Groucho Marx voice.

There are many small bodies orbiting the sun - trillions of asteroid and comets. Some are big (many miles across), some small. None of them are considered planets, however.

Sedna is the suggested name. The IAU may indeed make teh name official in a future meeting. Many of the Roman and Greek names are already assigned. Plus, I think the IAU wants to be inclusive of more cultures in future naming of major bodies.

Naming guide:

Minor asteroids are named by usually honoring people, places, things and events. There are many living people who have an asteroid named after them by the IAU.

Major Asteroids (minor planets) have mythological names, as do planets and their major moons.

Comets are named after their discoverer(s). Hale-Bopp is Alan Hale and Tom Bopp, the latter of whom I just spent some time with, as he was just in town staying with my boss. Great guy. You'll also see comet names (like the ones coming up this spring) named after the research project that discovered them.

All of these objects also have catalog have less exciting catalog designations as well (e.g. 422).

The guy from Gilligan's Island?

Whoa there little buddy!

Re: The palindrome of bolton would be notlob.....it don't work.
 

Tommy Shaw to that guy: "You've got too much (clap clap) time on your hands and it's ticking away with your sanity."

Well Yesspaz, the orbit of a comet is absolutely different to the orbit of a planet, it's not heliocentic because it crosses the orbits of other planets, the orbit of a planet is almost perfectly heliocentric and independant to other plamets, unless something really catastrophic happens).

Of course the comets have other features that planets don't have like tail, nucleus, coma, etc.

Iván

interesting debate
 

I'm a meat and potatoes guy, and I know only a little about this, but I do know Ivan's a lawyer and Yesspaz is an accomplished debater, so this is fun......

Maybe Avian can be the moderator.....

Sorry Ivan but............
 

Pluto IS a planet and it's orbit crosses that of Neptune. I think that at the moment or at least until recently Neptune was the furthest planet from the sun.

Jupiter, The Bringer of Jollity
 

Well, Gustav Holst crosses the orbit of Emerson, Lake and Powell, King Crimson, and possibly others.

:D

and Manfred Mann, too
 

Neptune's just weird, with the way it spins, etc. I think we should impeach Neptune.

And can we have a planet Goofy if we have a Pluto? Oh yeah, that's Earth.

many qualifications
 

There are many qualifications to make something a planet. Crossing orbits or not is not one of them (good call KW). The meteor belt between Mars and Jupiter fits that scenario, but thier not planets. All I'm saying is that there are many criteria. I don't know them all. While I think it'd be super-cool if Sedna is a planet, I think the scientists are correct to be cautious and wait and see for sure, doing more research.

Re: many qualifications
 

While I'm all for scientific prudence and all, my biggest question is: what's the difference? Is it going to affect anything at all if it's considered a planet or an Oort Cloud Object or perhaps Jimmy Hoffa's Final Resting Place? Will it affect the research that's done on it? Or will it just totally bugger up all the Astrological charts that have been drawn up for centuries?

If there's a sound scientific reason for it, I suppose it's OK (like they need MY permimssion :rolleyes: ) but it just strikes me as a whole lot of arm waving and histrionics for nothing.

Am I missing something?

You're right - but -
 

I'm sure it's important to the ones dealing with and classifying such things. Sort of like me trying to explain the difference between a Controller and a Comptroller.

I do agree about classifications - my #1 beef when discussing music................

Re: Re: many qualifications
 

I think the difference is that planets have a certain status that's different than other objects. Elementary school students learn the names of the nine planets. They don't learn about Oort Cloud objects or the dozens of comets. They don't learn the names of the asteroids or the names of the many moons. Planets have some sort of mystical ascribed status.

In other words, it's totally freaking cool to say, "We've got a tenth planet!" It's not so cool to say, "We've got a 35th Oort Cloud Object!"

Agree Yesspaz didn't remembered Pluto's weird orbit, but at least is mostly heliocentric.

Agree with that.

Iván

We didn't make this fuss before......
 

when the minor planet Chiron was discovered between Saturn and Uranus. It was widely believed that this was either a dead comet ot the brightest of a group of asteroids between Saturn and Uranus. I sort of lost touch a bit on that one.

btw. It's got a bit confusing for the mildly dyslexic when they named Pluto's satellite Charon.

Re: We didn't make this fuss before......
 

huh? man, how did I miss this one? Info Avian!

Chiron is a minor body discovered by Charles Kowal based on fotographs on 18 and 19 October 1977.

From the start it was almost certain it wasn't a planet or planetoid In 1988 a tail was observed, indicating was a comet bigger than anyone seen before.

Iván

The orbits of most comets are most DEFINATELY heliocentric (they orbit the sun). The fact that their perihelion (closest approach to the sun) is inside the orbits of the other planets doesn't mean anything. Long period comets are in highly elliptical orbits, their periods being measured in many decades - some in millenia. Some comets eventually break up completely after repeated trips to the inner solar system, if they come in that far.

Some planets have very circular orbits like the earth, others are more elliptical, like Pluto (and certinaly Sedna).

More information about Chiron and the Centaur objects can be found here.