Discovery : The 10th Planet of our Solar System ?

harlequin2902 · Post by **harlequin2902** » Tue Mar 16, 2004 1:07 pm

Have you seen the small article on the lower half of the front page of the Straits Times today (16/3) ? Hm, seems like scientists (California Institute of Technology) have discovered the 10th planet ?

This was done using the new Spitzer Space Telescope.

Not much information is available in that short article, but from it we know that it's been named 'Sedna', is ~ 10 billion km from Earth and has a diameter of ~ 2,000km (Pluto is ~ 2,324km). Due to it's highly eliptical orbital path around the Sun (loops as far out as 135 billion km from the Sun), it takes 10,500 years to complete the circuit !

Post by **weixing** » Tue Mar 16, 2004 1:31 pm

Hi,
I don't think it will be consider as a planet, it just too small.

By the way, most astronomer agree that Pluto shouldn't be classified as planet and should be classified as a giant Kuiper Belt Object, because it just too small and there are some moons in the solar system which are bigger than Pluto.

Hope they come up with a definition for a planet. Have a nice day.

Post by nF » Tue Mar 16, 2004 2:36 pm

Or maybe they will classified it as a minor planet.

Post by **zong** » Tue Mar 16, 2004 4:23 pm

No I doubt so it'll be called the 10th planet. My reasons:

1) It takes just too long to complete the orbit.
2) Pluto was called a planet because the Kuiper Belt was not yet found. Otherwise we'd only have 8 planets.
3) Recently the largest Kuiper Belt object found was about 60% the size of Pluto. If such a planet bigger than Pluto is found in the Belt then it is only further proof that Pluto is a KBO.
4) Due to its highly elliptical orbit it would more be classified as an object captured by the sun, rather than a planet orbiting the sun.

This is just my opinion, don't take them for facts tho!

harlequin2902 · Post by **harlequin2902** » Tue Mar 16, 2004 6:36 pm

Yes, that's basically how the article ended -> "...The discovery is likely to reignite the debate about what makes a planet. Some scientists have long argued that Pluto is too small to be called a planet, and that it is just another object floating around the solar system..."

Let's see if there are any updates in tomorrow's papers.

Post by **Airconvent** » Tue Mar 16, 2004 11:39 pm

yup...already read it earlier on bbc's avantgo channel on my pda. :-)
To get yourselves in perspective, this object is tiny (1700km in diameter at most) , cold, non reflecting, and THREE times the distant as far as Pluto and its orbit takes 10500 earth years.

And yet we were able detect it ....what a superb telescope they used.
Way above any Televue or Takahashi!

The previous object, Quoao (or something like that) did not qualify as a planet because it did not have a fixed orbit around the sun. this new object (named sedna for now) was observed to have a fixed orbit which is why it is candidate to be called a planet. The final confirmation today is that they now suspect the new object has a moon based on its too slow rotation (HOW DO THEY FIND OUT ABOUT THESE THINGS? amazing!)

It is also quite firm that the international naming body will reject the name Sedna chosen by the founder as it will deviate from the trend of naming the planets after mythological characters.

rich

Post by **weixing** » Wed Mar 17, 2004 12:00 am

Hi,
I also just read the article from space.com. They discover the object using a 48inch Samuel Oschin Telescope at Caltech's Palomar Observatory, so I don't think you are able to see it using any Televue or Takahashi telescope...

Anyway, you can find an object's companion by detecting the wobble of the object. This method can also be use to find planets of other star or small companion star.

By the way, Sedna mean goddess of the sea for Arctic dwellers...

Have a nice day.

Post by **Airconvent** » Wed Mar 17, 2004 12:27 am

weixing wrote:Hi,
I also just read the article from space.com. They discover the object using a 48inch Samuel Oschin Telescope at Caltech's Palomar Observatory, so I don't think you are able to see it using any Televue or Takahashi telescope...

Anyway, you can find an object's companion by detecting the wobble of the object. This method can also be use to find planets of other star or small companion star.

By the way, Sedna mean goddess of the sea for Arctic dwellers...

Have a nice day.

Then must call "Samuel" asap to look at his new 48" scope!

I do know about the wobble technique but this nbew object's moon was discovered when astronomers found that it was rotating too slow for its size. They suspected another object, likely revolving around it , is the cause of the slow down. I very much doubt they can actually photograph this object's moon as even the object itself is a challenge. Our sun would only appear as a bright star at that distance, probably much like how sirius look to us here.

harlequin2902 · Post by **harlequin2902** » Wed Mar 17, 2004 7:28 pm

Update : 17/03

Ok, after the initial speculation from the media that the 10th planet had been discovered, in an official release, the team now classifies it as "the most distant object known to orbit the Sun"

The team leader also proposed that this object is so very far away that it may not even be a KBO but could be the very first observed member of the Oort Cloud :o

The full article can be found on pg 12 of today's Straits Times (17/3) Home section.

Post by **zong** » Wed Mar 17, 2004 10:22 pm

harlequin2902 wrote:Update : 17/03

Ok, after the initial speculation from the media that the 10th planet had been discovered, in an official release, the team now classifies it as "the most distant object known to orbit the Sun"

The team leader also proposed that this object is so very far away that it may not even be a KBO but could be the very first observed member of the Oort Cloud :o

Whoa! That sounds more and more crazy to the public! Gosh.. Imagine having to explain to them what is the Oort Cloud and the Kuiper Belt, when they approach us while we are observing.. That would kill of their interest in Astronomy quickly, too..