Planet Ten discovered by Spitzer telescope

[Diamond]

..could be bigger than Pluto. Called Sedna (is that because its the reverse of "Andes"?)

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

Astronomers discover 'new planet'
By Dr David Whitehouse
BBC News Online science editor

Astronomers have detected what could be the Solar System's 10th planet.
Found further away than other planets by the recently launched Spitzer Space Telescope, it has been called Sedna after the Inuit goddess of the ocean.

Observations show it is about 2,000 km across and it may even be larger than Pluto, which is 2,250 km across.

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

The Hubble Space Telescope has also seen it.

Details will be announced by the US space agency Nasa later on Monday.

[Kebsis]

Interesting, but are we going to call every large object we find in the Kuiper Belt a planet now?

[AK]

Interesting, but are we going to call every large object we find in the Kuiper Belt a planet now?

It's not a KBO... it's way farther out.

[kucharek]

Called Sedna (is that because its the reverse of "Andes"?)

..., it has been called Sedna after the Inuit goddess of the ocean.

Read your quotes... ;-)

Harald

[Grand Vizier]

Will that name have been sanctioned by the IAU already? Because I was immediately thinking that, if this object is to be regarded as Planet 10, then the old naming system (Roman gods) would usually come into force. (I think Proserpine, consort of Pluto, used to be a favourite for planet 10 - though it could be argued that Charon should have had that name.)

Ah, what's in a name - Sedna's not too bad, really - after all, Uranus could have been named 'The Georgian Planet' or just plain 'George'.

[Richard of Chelmsford]

Interesting, but are we going to call every large object we find in the Kuiper Belt a planet now?

Well, like the BBC man said it is 1300 miles across which makes it bigger than Pluto, so I suppose it will have to qualify, Kuiper belt or no.

What do you think it would be like on the surface?

What would the sun look like?

Just a big star, I suppose.

[Grand Vizier]

Well, like the BBC man said it is 1300 miles across which makes it bigger than Pluto, so I suppose it will have to qualify, Kuiper belt or no.

Could get messy. I actually don't think it's important in astronomical terms whether Sedna and/or Pluto are designated planets, but in popular - and educational - terms it would help if people could be given a definite number of planets for the Solar System. I can see several possibilities:

1) Retain Pluto as a planet, and add Sedna as the tenth, since it is presumably, in its original orbit. 10 planets. (I think this is the likeliest)

2) Demote Pluto, because of its peculiar orbit, and make Sedna No 9. (I think this is unlikely). 9 planets.

3) Retain Pluto and ignore Sedna, on the basis that 'planet' designations are officially obsolete, i.e. the polling is frozen. 9 planets (this just doesn't seem right - what happens if we find something, say, 5,000 km in diameter out there?)

4) Decide that Pluto is a KBO, not a planet, and freeze the number at 8. Same sort of justification as 3, same problems.

And I wonder what happens if we find more. A 16-planet solar system, say, might seem a bit daft if the 8 outermost members were just 2,000km bodies...

I think a BABB poll might be handy here, but it should wait until after the press conference.

What do you think it would be like on the surface?

Cold. Dark. But maybe it could retain a thin, seasonal, atmosphere like Pluto. Guess that depends on surface composition which is going to be real hard to determine.

[Manchurian Taikonaut]

Planet Found On The Outer Rim Of Sol

http://www.spacedaily.com/news/kuiper-04b.html

more news

[Grand Vizier]

Seems we've now got two threads going on this:

http://www.badastronomy.com/phpBB/viewtopic.php?t=11977

Most intriguing, anyway, is the suggestion it may be an Oort Cloud object, presumably at or near perihelion.

http://www.hohmanntransfer.com/news.htm

Now that would be a first. Can't hardly wait till 18:00 GMT...

[edited to include Tenagra quote]

Extra from http://www.tenagraobservatories.com/:

WE CONGRATULATE MICHAEL BROWN ET AL ON THE MOST ASTOUNDING DISCOVERY IN THE OUTER SOLAR SYSTEM SINCE CLYDE TOMBAUGH FOUND PLUTO IN 1930.

Wish they weren't shouting, though - and I certainly hope it's going to live up to all this...

[StormSeeker]

Interesting, but you know the woo woo's are going to be all over this.

But a good question... How big does an object have to be to be considered a planet? Where is the cut-off point mass wise?

[Normandy6644]

Interesting, but you know the woo woo's are going to be all over this.

But a good question... How big does an object have to be to be considered a planet? Where is the cut-off point mass wise?

Yeah, they will be. Until they realize that if there really were a conspiracy, we never would have been told about it.

As for planet size, do you mean upper or lower limit? The upper limit is a bit bigger than Jupiter (not sure exactly how much) because the core would become dense enough to ignite and begin to fuse element, i.e., become a star. The lower limit is, well, sort of difficult, since the definition of "planet" comes up. If our moon were orbiting between the Earth and Mars (around the sun, of course), it would probably be considered a planet.

[Grand Vizier]

Interesting, but you know the woo woo's are going to be all over this.

I think they already are. I haven't had the heart to look at primary sources, but I guess brave souls will be posting their findings to the Planet X forum shortly...

But a good question... How big does an object have to be to be considered a planet? Where is the cut-off point mass wise?

It's not just mass. Any of the moons of Jupiter, or Titan, or our Moon would be considered a planet if they were orbiting the Sun independently - and in fact, a good case can be made that Earth-Moon is a double-planet system.

I don't think there is a good definition anymore - it was convenient to refer to 'major planets and 'minor planets' once, but this object seems to be twice the diameter of Ceres, the largest asteroid/minor planet. It could be argued that 'planet' is now just a historical concept, but it's sort of convenient, I guess.

[Spacewriter]

Will that name have been sanctioned by the IAU already? Because I was immediately thinking that, if this object is to be regarded as Planet 10, then the old naming system (Roman gods) would usually come into force. (I think Proserpine, consort of Pluto, used to be a favourite for planet 10 - though it could be argued that Charon should have had that name.)

Ah, what's in a name - Sedna's not too bad, really - after all, Uranus could have been named 'The Georgian Planet' or just plain 'George'.

I think it should be "Bob."



Remember when space station was going to be called "Freedom" and then when the design got downsized they shortened the name to "Fred?"

[Eta C]

Interesting, but are we going to call every large object we find in the Kuiper Belt a planet now?

Well, like the BBC man said it is 1300 miles across which makes it bigger than Pluto, so I suppose it will have to qualify, Kuiper belt or no.

What do you think it would be like on the surface?

What would the sun look like?

Just a big star, I suppose.

space.com puts its at between 800 and 1100 miles across which is about 3/4 the size of Pluto. This contradicts the headline of the article somewhat as that talks about a "Huge Mini-World." I suppose it's huge by KBO standards, but it's not the monster world the WW's want.

On the name, the article says Sedna is the Inuit goddess who the created arctic sea creatures. So it would fit into the naming scheme and is somewhat appropriate for what must be a very cold place.

[informant]

This is likely the first detection of the long-hypothesized "Oort cloud," a faraway repository of small icy bodies that supplies the comets that streak by Earth. Other notable features of Sedna include its size and reddish color.
http://www.spitzer.caltech.edu/Media.../release.shtml

Red is an unexpected color, isn't it? Isn't the Oort Cloud supposed to be made up of comets?

It's not just mass. Any of the moons of Jupiter, or Titan, or our Moon would be considered a planet if they were orbiting the Sun independently - and in fact, a good case can be made that Earth-Moon is a double-planet system.

I don't think there is a good definition anymore - it was convenient to refer to 'major planets and 'minor planets' once, but this object seems to be twice the diameter of Ceres, the largest asteroid/minor planet. It could be argued that 'planet' is now just a historical concept, but it's sort of convenient, I guess.

What we need to do is define subclasses of planets/moons --- and asteroids/moons. The distinction between "planet" and "moon" has always seemed a bit arbitrary to me, because in the chaotic early days of a solar system it's possible that a "planet" or "asteroid" will be captured by a bigger "planet" or "asteroid", and become a "moon".

[Russ]

Although I think it is probably a typo, space.com has some bad astronomy in their article about Sedna. I quote:

"Pluto is about 1,413 miles (2,274 kilometers) wide. Sedna is estimated at no more than 1,100 miles (1,770 kilometers) in diameter. It may be the largest object in the solar system after Pluto, but more observations are needed to pin that down."

I believe they mean next smaller object after pluto, as Pluto is not the largest object in the Solar system.

[ZaphodBeeblebrox]

Well at least if we keep discovering Planet sized bodies it'll make Astrology Simpler.

12 Houses, 6 Planets, Two per House, is the way the System was Designed.

Now, we have 3 Planets playing Piggy-Back.

But, if there were 12, oh what a System that would be! :^o

[Krevel]

I just heard an astronomer on NPR discussing this. (Sorry, don't recall his name.) He said that the size (his term) is probably about half that of Pluto, but that it may be as big as Pluto - they just don't know yet.

[nebularain]

Although I think it is probably a typo, space.com has some bad astronomy in their article about Sedna. I quote:

"Pluto is about 1,413 miles (2,274 kilometers) wide. Sedna is estimated at no more than 1,100 miles (1,770 kilometers) in diameter. It may be the largest object in the solar system after Pluto, but more observations are needed to pin that down."

I believe they mean next smaller object after pluto, as Pluto is not the largest object in the Solar system.

But they did say "the largest object in the solar system after Pluto. (??)

[Russ]

Although I think it is probably a typo, space.com has some bad astronomy in their article about Sedna. I quote:

"Pluto is about 1,413 miles (2,274 kilometers) wide. Sedna is estimated at no more than 1,100 miles (1,770 kilometers) in diameter. It may be the largest object in the solar system after Pluto, but more observations are needed to pin that down."

I believe they mean next smaller object after pluto, as Pluto is not the largest object in the Solar system.

But they did say "the largest object in the solar system after Pluto. (??)

Yep. Just read my quote above. (I've added bold to the specific words) I just cut and pasted it from the site.

[Mokele Mbembe]

I think they may mean "after Pluto" in terms of distance from Sol.

[JohnOwens]

The idea I got from it was a sequence of Solar System objects, with the Sun first, Jupiter second, and so on until Pluto, and after that you have Sedna. Just the way it ought to be. :-k

[ToSeek]

Stray star may have jolted Sedna

Sedna, the most distant planetoid ever seen in the Solar System, probably got kicked into its orbit when a star swept past the Sun more than four billion years ago, suggest the first detailed calculations of the object's origins.

The research supports the leading theory of Sedna's origins but also leaves open more outlandish possibilities.

[ToSeek]

Giant Kuiper Belt Planetoid Sedna May Have Formed Far Beyond Pluto

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.

In a report published in the January 2005 issue of The Astronomical Journal, planetary scientist Dr. Alan Stern of the Space Science and Engineering Division at Southwest Research Institute® (SwRI®) shows Sedna could have formed far beyond the distance of Pluto.

"If this is actually what happened," Stern points out, "it would indicate that our solar system's planet factory operated across a much larger region than previously thought." It would also indicate that the mysterious Kuiper Belt "edge" near 50 AU (one AU is the distance from the Earth to the Sun) is not an outer edge, but simply the inner edge of an annular trough, or gap, that is carved out of a much broader structure that has been called the "Kuiper disk."

[ToSeek]

Case of Sedna's Missing Moon Solved

Sedna is rotating much more rapidly than originally believed, spinning once on its axis every 10 hours. This shorter rotation period is typical of planetoids in our solar system, requiring no external influences to explain.

"We've solved the case of Sedna's missing moon. The moon didn't vanish because it was never there to begin with," said Gaudi.

[Senor Molinero]

Oh it all falls into place now. That's why astrology has been so innacurate for so long. Until 1930 the astrologers were unaware of the powerful influence of Pluto. Now they have to take Sedna (and Quoaur and all of the asteroids and KBOs) into account. It's good to know that our future will be much more predictable from now on. :roll:

Cheers
Molinero


"Let's burn down the observatory so this will never happen again!"

[Antilles]

Oh it all falls into place now. That's why astrology has been so innacurate for so long. Until 1930 the astrologers were unaware of the powerful influence of Pluto. Now they have to take Sedna (and Quoaur and all of the asteroids and KBOs) into account. It's good to know that our future will be much more predictable from now on.

[ToSeek]

Distant planetoid Sedna gives up more secrets

The distant planetoid Sedna appears to be covered in a tar-like sludge that gives it a distinctly red hue, a new study reveals. The findings suggests the dark crust was baked-on by the Sun and has been untouched by other objects for millions of years.

[One Day More]

Oh bother, if Sedna is gonna be a planet, looks like I'll have to rewrite my musical to include it.

[Russ]

I just found an interesting item in the Sunday Comics in the Cincinnati Enquirer for April 17, 2005. It's titled "You Can" by Jok Church. People write in asking questions and this guy gives answers that kids can understand. This weeks question:

"What's the difference between moons and planets?" signed Bette Greep.

"Dear Bette,

A beautiful thing is that knowledge grows. I doesn't sit there still and static. In the last six years humans have discovered 79 moons that we didn't now about before. The total is 139 moons in our solar system-until knowledge grows more.

The biggest difference between a planet and a moon is where it is. Planets orbit around stars, like our sun. Moons orbit around planets."

They even took the time to list out the names of the currently named moons and indicate where & how many unnamed moons there are. They also have a little diagram that roughly shows the relative size of the 9 planets and another diagram with pictures of Mimas and Phobos to show how moons come in different sizes.

Sorry I had to type all of that out but the Enquirer didn't have an archive of the Sunday Comics on their web site.