Do you think Sedna is the 10th planet?

[DJ critikaL]

http://news.bbc.co.uk/2/hi/science/nature/3511678.stm

http://newsimg.bbc.co.uk/media/images/39890000/jpg/_39890536_sedna_nasa_203.jpg

Astronomers have detected what could be the Solar System's 10th planet.
It was first seen by astronomers using California's Mount Palomar Observatory, and has been given the name "Sedna" after the Inuit goddess of the ocean.

Observations show it measures about 1,180-2,360km (730-1,470 miles) across, making it similar in size to Pluto.

Astronomers now say they have evidence that Sedna has its own moon, although this needs to be confirmed, and is also very red in colour.

There is likely to be some debate about whether it qualifies as a true planet, but some scientists are already saying it re-defines our Solar System.

Further than Pluto

Sedna, or 2003 VB12, as it was originally designated, is the most distant object yet found orbiting our Sun. It is three times further away than Pluto (average distance to the Sun is 5.9 billion km or 3.6 billion miles).


It was discovered using the Mt Palomar facility in November by astronomers from the California Institute of Technology, Yale Observatory and the Gemini Observatory.
Dr Mike Brown of the California Institute of Technology, US, leader of the research team that found the body, said he did not believe it was a true planet.

He suggested this "planetoid" is about half rock and half ice mixed together, but further work is needed to verify this.

The scientists say that its rotation on itself is relatively slow, suggesting it could have a satellite in orbit around it.

Follow-up studies by the Tanagra Observatory have measured the thermal radiation coming from Sedna to determine how hot it is, and therefore provide some estimate of its size.

Researchers believe that Sedna's surface temperature is about -240 degrees Celsius (-400 degrees Fahrenheit).


Click here to see Sedna's size and distance from the sun
This estimate is uncertain but the object is likely to be between half the diameter of Pluto (2,360km or 1,470 miles) and Pluto's size; though some astronomers think it could be larger than the ninth planet itself.

From the observations made so far, astronomers have determined Sedna's orbit to be a very large one.

It is currently 90 times the Earth-Sun distance away (149 million km or 93 million miles), but its orbit can take it 10 times further away still.

Small worlds

Although Sedna could be a so-called Kuiper Belt object, its discoverers are unsure if it is as they consider it to be unlike any other object yet found.

The KB contains hundreds of known objects and astronomers believe there are many more awaiting discovery. Most are small worlds of rock and ice but some could rival Pluto in size.


KUIPER BELT OBJECTS
Icy planetary bodies that orbit beyond Neptune in the distant region of the Solar System
More than 400 such objects are currently known
They are believed to be remnants of the formation of the Solar System and among the most primitive objects available for study
In recent years, astronomical work has thrown up several big objects. Quaoar, found in 2002, is about 1,200km (745 miles) across. Ixion, discovered in 2001, is 1,065 km (660 miles) wide. Varuna, detected in 2000, has a diameter of approximately 900 km (560 miles).

And only in February this year, scientists picked up the object 2004 DW, which is though to be 1,800km (1,120 miles) across.

Is it a planet?

The new discovery will reignite the debate about what constitutes a planet.

One group of astronomers believe that Pluto is not a true planet but merely one of the largest of a vast number of minor objects in the outer Solar System.

The alternative standpoint is that Pluto is a planet and those who believe that will have to classify Sedna as the 10th planet.

The name Sedna has been provided by its discoverers.


However, if its planetary status is confirmed, it may be that astronomy's governing body, the International Astronomical Union, will want to reconsider this, to make it more consistent with the mythological names of other planets.

http://newsimg.bbc.co.uk/media/images/39891000/gif/_39891622_sedna_info_416.gif

[Bigsky770]

. . .Good to have you with us, moved this new thread over to the "Science, Nature & History" section as it's more appropriate for this topic. . .

. . .I'm voting "No", If it's anything at all I think it'd be considered as a "Planetoid" as opposed to a "Planet", it's just too small in size, and as well at 3X's the distance of Pluto, doesn't that qualify it as being 'out-of-bounds' for its' inclusion within our solar system?

. . .I DID think it was pretty cool though when it was discovered; there's so-much out there we have YET to find! Again, Welcome to the "Forum", take a look around/Enjoy! :D

Joe (Bigsky770) :vbroll:

[ALIENTheorist]

I have one thing to say haven't scientists already proven the existance of Sedna as our tenth planet and wasn't it like the size of Saturn...

[cjpluss]

Here's what i think:
If it's smaller than pluto, its definitely not a planet, as pluto is on the edge of the planet/asteroid line. Some even argue that pluto isn't a planet, but who gives a f***. In my opinion, the more planets the better!

[lazserus]

Sedna is smaller than Charon, Pluto's moon, and is not spherical. It is not classified as a planet.

[Zach]

I know this has nothing to do with the topic at hand, but nice avatar Lazserus

[lazserus]

Thanks, bud. It's fun.

Back to the topic, if anyone is curious I have two greatly informative links about planetary classification, Pluto, and why planets are spherical.

What constitutes a planet and is Pluto one? (http://www.sciam.com/askexpert_question.cfm?articleID=0009D053-74A9-1C72-9EB7809EC588F2D7&catID=3&topicID=2)

Why are planets spherical? (http://www.sciam.com/askexpert_question.cfm?articleID=000D93E1-778C-1C72-9EB7809EC588F2D7&catID=3&topicID=2)

[RavenWhitefang]

SwRI Researchers Show Planetoid Sedna May Have Formed Far Beyond Pluto

Boulder CO (SPX) Jan 12, 2005 Recently, astronomers reported the surprising discovery of a very large diameter Kuiper Belt planetoid - (90377) Sedna - on a distant, 12,500-year-long, eccentric orbit centered approximately 500 astronomical units from the Sun.
Sedna's estimated diameter is about 1,600 km, two-thirds that of Pluto. Initial studies of Sedna's origin have speculated that it might have been ejected from the giant planets region of our solar system far inside the orbit of Pluto, or perhaps was captured from a passing star's Kuiper Belt.

Full Story HERE (http://www.spacedaily.com/news/kuiper-05a.html)

[Dhanishta]

Sedna could very well be one of the "evil winds" ie; moons which orbit Nibiru / Marduk. Or it might not have anything to do with Marduk at all and just be a floating glob of rock and ice. It could also be a comet from the kupier belt or oort cloud which has lost its puff {ie; no tail to discern it as a comet} because it is too far away from the sun. There's a million possibilities to consider regarding it.
No I dont think it is the 10th planet. I think it is more likely to be a moon as it is moon size and may not qualify to be a planet in its own right.

[dutchie]

Sedna definitely is on its own. A moon is always orbiting a planet. It's a planetoid.

[RavenWhitefang]

Sedna definitely is on its own. A moon is always orbiting a planet. It's a planetoid.

Not nessecarily true, Venus and Mercury have no satellites.

[stewey]

Sedna could very well be one of the "evil winds" ie; moons which orbit Nibiru / Marduk. Or it might not have anything to do with Marduk at all and just be a floating glob of rock and ice. It could also be a comet from the kupier belt or oort cloud which has lost its puff {ie; no tail to discern it as a comet} because it is too far away from the sun. There's a million possibilities to consider regarding it.
No I dont think it is the 10th planet. I think it is more likely to be a moon as it is moon size and may not qualify to be a planet in its own right.

Nibiru/Marduk does not exist.

[ALIENTheorist]

just wondering where did this Nibiru/Marduk thing came from...

[dutchie]

Not nessecarily true, Venus and Mercury have no satellites.
That's not what I meant... I just meant that Sedna is not a moon, as was suggested in the post.

[evil_kenshin]

well its debatable, technicly it is a planet but due to its size cannot be considered one but to the people who said its out of our solar system, it is just in it, just very close to the border though

[dutchie]

well its debatable, technicly it is a planet but due to its size cannot be considered one but to the people who said its out of our solar system, it is just in it, just very close to the border though
Technically, it is a planetoid.

[ALIENTheorist]

well its debatable, technicly it is a planet but due to its size cannot be considered one but to the people who said its out of our solar system, it is just in it, just very close to the border though


how can we define the border of our solar system?

[lazserus]

The Kepler Belt is the border of our solar system. There's not really anything else for thousands of AUs outside of that asteroid field.

[dutchie]

Isn't that the Kuiper Belt, laz?!?
(in defense of my co-dutchies...)

[evil_kenshin]

Technically, it is a planetoid.


hmm? ok i take my earlier comment back, but i think your right its not Kepler Belt since wasn't kepler some scientist?

[dutchie]

Johannes Keppler (or Kepler - both are OK) was an astronomer, like Kuiper.

More on Gerard Peter Kuiper here (http://quest.arc.nasa.gov/lfs/kuiper-bio.html).

A LOT on Johannes Keppler here (http://www.astro.uni-bonn.de/~pbrosche/persons/pers_kepler.html).

Keppler was 2 centuries before Kuiper.

And yes - it IS the Kuiper Belt.

[lazserus]

Oops, I meant Kuiper. I think I was drunk.

[ALIENTheorist]

Oops, I meant Kuiper. I think I was drunk.

it's ok I think I was drunk when I voted :alcoholic lol jk back then I though I read that planet x was bigger than pluto guess not..... if atleast I would know how to change my vote

[Protostar]

Sedna is a sattellite. Not a planet.

[Swordsbane]

If Pluto with it's wild orbit can be considered the 9th planet, then Sedna has every right to be the 10th, unless they find something between Sedna and Pluto. There was talk once about Ceres being designated a planet, but they decided it would be too confusing being mixed in with the asteroid belt.

[lazserus]

Pluto's highly elliptical orbit has nothing to do with it being classed as a planet. One requirement of a planet is to be spherical in shape. Sedna is a lumpy mess.

[Swordsbane]

Pluto's highly elliptical orbit has nothing to do with it being classed as a planet. One requirement of a planet is to be spherical in shape. Sedna is a lumpy mess.

Yeah, I heard that spherical is a requirement, but that's an arbitrary silliness, like saying that something must be green to be classified as a plant. As far as I'm concerned, if it's big enough to have an atmosphere (even if it doesn't have one) then it's a planet. Some of Saturns and Jupiters moons are as big as other planets in the solar system. We call them 'moons' because they orbit another planet. Sedna orbits the Sun, and it's size range puts it in the same class as other moons at least, and it's not much smaller than Pluto. Pluto's eccentric orbit means it is probably not from our solar system. It's moon Charon is almost as big as it is, yet we discovered Pluto first so we call it a planet, and Charon is a 'moon' The whole thing is pretty arbitrary. The "rules" for planet classification leave a lot of wiggle room. If Jupiter was a bit bigger and had more mass, it could generate it's own fusion reaction and become a sun. Then we'd be a double star system and all of Jupiters moons (those that were still there) would magically become planets.

Sedna can be a planet, unless we find out it's the biggest comet anyone has ever seen. Even then I wouldn't be against calling it a planet.

BTW: We thought Pluto was lumpy until we discovered the lump was Charon, yet we still called it a planet.

[Mezurashi]

Pluto's highly elliptical orbit has nothing to do with it being classed as a planet. One requirement of a planet is to be spherical in shape. Sedna is a lumpy mess.


the shape of a mass has NOTHING to do with its classification - it is the MASS involved.

**Translation** Planets Big - not Planets Small...

[Swordsbane]

the shape of a mass has NOTHING to do with its classification - it is the MASS involved.

**Translation** Planets Big - not Planets Small...

Our moon is bigger and more massive than Pluto. The Earth and the moon orbit around a common center that is located only a little bit beneath the surface of the Earth. Why is the Moon not a planet, yet Pluto is? There is very little difference between the two.

[lazserus]

Wow, I suppose I'll have to link this AGAIN. I'll leave planetary classifications up to those qualified to make such classifications.

http://www.sciam.com/askexpert_question.cfm?articleID=0009D053-74A9-1C72-9EB7809EC588F2D7&catID=3&topicID=2

Pluto isn't considered the planet solely on the fact that it was discovered first. Charon, all though nearly the same size as Pluto, is actually Pluto's satellite due to orbit specifications. Charon orbits Pluto, period. Thus, it is Pluto's satellite. The same goes for the moons of Jupiter. Just because they are planetary in size does not mean they qualify as planets.

Planetary classifications may be slightly arbitrary but they hold enough water to be considered a standard by the vast majority of the scientific community. If Sedna is to be considered a planet based on the fact it has an atmosphere, then there are probably several thousand planets in our solar system. A line has to be drawn and it has been drawn, whether you like the results or not.

[Mezurashi]

Question - does anyone remember back when the Tenth Planet was named Persephone? I know it was used in Science Fiction and stuff like that, but I heard once (can't find any references for it) that NASA was actually looking for it. is this a folk tale or just part of the long and twisted history of astronomy?

and has anyone heard anything about the Sun having a dim brown dwarf companion we haven't found yet? off topic, I know, but related. can't provide any links to anything on this one, it's all hearsay to me...

[Swordsbane]

Wow, I suppose I'll have to link this AGAIN. I'll leave planetary classifications up to those qualified to make such classifications.

http://www.sciam.com/askexpert_question.cfm?articleID=0009D053-74A9-1C72-9EB7809EC588F2D7&catID=3&topicID=2

Pluto isn't considered the planet solely on the fact that it was discovered first. Charon, all though nearly the same size as Pluto, is actually Pluto's satellite due to orbit specifications. Charon orbits Pluto, period. Thus, it is Pluto's satellite. The same goes for the moons of Jupiter. Just because they are planetary in size does not mean they qualify as planets.

That's my point. It is mostly arbitrary. Most often a moon is only a moon because it orbits something already designated as a planet. My point about Jupiter is that if Jupiter were a star, then it's moons would be called planets even if all their characteristics were the same as they are now. Point of fact: Charon does NOT orbit Pluto. Pluto and Charon meet ALL the criteria for a double planet system. They orbit a common center. This common center is closer to Pluto than Charon because Pluto is more massive.


Planetary classifications may be slightly arbitrary but they hold enough water to be considered a standard by the vast majority of the scientific community. If Sedna is to be considered a planet based on the fact it has an atmosphere, then there are probably several thousand planets in our solar system. A line has to be drawn and it has been drawn, whether you like the results or not.

I understood the question to mean; should Sedna be classified as a planet or an asteroid. Sedna cannot be classified as a moon, and I did not mean to imply that moons that have atmospheres should not be reclassified as planets. Sedna appears all alone out there, and is a lot like Pluto when it was first discovered. If we can classify Pluto as a planet and not Sedna, then what is the reasoning behind that? To quote from that article you linked to: "It is a subjective question, one that has produced some passionate disagreements within the astronomical community." Where's this "line" you speak of?

[Rasher_hgr]

and as well at 3X's the distance of Pluto, doesn't that qualify it as being 'out-of-bounds' for its' inclusion within our solar system?(Bigsky770) :vbroll:
ok, in this here quote we have the words "out of bounds" and it's used in a place of this planet/maybe not a planet is "out of bounds" for our solar system. before the discovery of pluto, pluto was "out of bounds" but pluto's a planet...argue that please. have a GREAT day! :2thumbs:

[DJ critikaL]

Our moon is bigger and more massive than Pluto. The Earth and the moon orbit around a common center that is located only a little bit beneath the surface of the Earth. Why is the Moon not a planet, yet Pluto is? There is very little difference between the two.

Pluto isn't a moon because Pluto revolves around the SUN, not another planet. If Sedna isn't revolving around another planet, then it is a planet.