英语听力文摘492 塞德娜

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Sedna 塞德娜

(本文写于2004年)

Pluto is the last of the nine planets, and when it’s at its farthest point in its elliptical orbit, it’s the farthest planet from the sun. That's true, but incorrect. Well, what you said about Pluto is true, but you left out super-distant object is only found recently, such as Sedna. Sedna?

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. 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.

Sadly for Sedna, though, it’s way out there–about eight billion miles away. Eight billion? That’s a whopping three times farther from the sun than even Pluto is. 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.

Sedna is already fascinating folks, though, because it is very reflective and reddish colored, confusing astronomers as to what it might be made of. It also has a bizarrely elongated orbit, going around the sun only once every ten thousand years!

冥王星是九大行星中最后被发现的一颗。它处在椭圆轨道的最远点，同时也是离太阳最远的行星。那是事实，但不准确。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。塞德娜?

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。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。

然而遗憾的是，它离得很远，约有80亿英里远。80亿英里?那它与太阳的距离是冥王星与太阳距离的三倍远啊。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。

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。它还拥有奇怪细长的轨道，围绕太阳运行一周需要1万年。