Sedna

But Sedna may have a moon of its own , and if it were a lot closer , we might have called it a planet long ago .

但是塞德娜也许有其自己的卫星，而且如果它能离得更近，我们也许很久以前就称其为行星了。

Well , what you said about Pluto is true , but you left out super-distant object is only found recently , such as Sedna .

关于冥王星你所说的是对的，但是你忽视了超远距离的物体是最近才发现的，比如塞德娜。

Sadly for Sedna , though , it 's way out there - about eight billion miles away .

然而遗憾的是，它离得很远，约有80亿英里远。

Sedna is so distant , and tiny , that it was only discovered for the first time this year by astronomers at the California Institute of Technology in Pasadena .

由于塞德娜那么远又那么小，因此帕萨迪纳市加州理工学院的天文学家们于今年第一次发现它。

Sedna is already fascinating folks , though , because it is very reflective and reddish colored , confusing astronomers as to what it might be made of .

然而，塞德娜已经让很多人着迷了，因为它能反射太阳光呈微红色，使得天文学家们困惑它到底是由什么组成的。

No one could convincingly explain how the object , which Dr. Brown named Sedna , got there , and the hope was that the discovery of more Sedna-like worlds would provide enlightening clues .

布朗把它命名为赛德娜（Sedna）。没有人能够对这颗天体为何出现在那里作出令人信服的解释。科学家希望，将来发现更多的类似天体，从而提供能带来启发的线索。

And if so , why not Quaoar and Sedna , and several other worlds , which were smaller than Pluto , but not by much ?

而且如果这样的话，为什么夸欧尔、塞德娜及其它星体不是呢？它们比冥王星小些，但没小那多。

Sedna 's been dubbed a " planetoid " - think of it as a mini-planet , three quarters as big as Pluto . It 's smaller than our moon .

塞德娜被称为“小行星”，其体积大小为冥王星的四分之三，比月球小一点。

Come back in half a billion years , Dr. Brown said , and Sedna will be back in the Kuiper belt , while other Kuiper belt objects will have been pushed into elliptical orbits .

巴蒂金表示，五亿年后赛德娜会回到柯伊伯带，而其他天体也会被推入椭圆形轨道中。