Pluto may be a dwarf planet now, Clyde baby, but you're still the first American to discover a planet in my book.

现在，冥王星可能是个矮行星，但是，亲爱的克莱德，在我书中你仍然是第一个发现行星的美国人。

And so, Pluto is a dwarf planet.

因此，冥王星是矮行星。

What is a dwarf planet?

甚么是矮行星？

So the committee suggested it be called a dwarf planet.

所以委员会建议把它称为矮行星。

Pluto is now considered a dwarf planet dwelling in the Kuiper belt.

冥王星现在被认定为一颗处于柯伊伯带中的矮行星。

Nasa says the dwarf planet on the edge of our solar system is becoming increasingly red.

美国宇航局说，这颗太阳系边缘的矮行星正在越变越红。

So Pluto is classified as a dwarf planet, but no longer a planet in the solar system.

因此冥王星被归类为矮行星，但不再是一个行星在太阳系形成的奥秘。

These days it is classed as a"dwarf planet", one of at least five in the solar system.

目前，它被归为“矮行星”，在太阳系中至少是五颗之一。

It is the solar system's fifth dwarf planet, in the same category and region as Pluto.

这是太阳系第五颗矮行星，与冥王星属同一类别同一区域。

And until Pluto crashes into many of them and gains mass, it will remain a dwarf planet.

除非能撞上它们之中的许多个，并获取更多质量，否则冥王星仍将是一个矮行星。

In 2005, he made a key discovery that led scientists to reclassify Pluto as a dwarf planet.

2005年，他的一项重要发现引导科学家们将冥王星重新归类为矮行星。

Between the orbits of Mars and Jupiter lies the asteroid belt, which includes the dwarf planet Ceres.

在火星和木星的轨道间分布着小行星带，之中有一颗矮行星谷神星。

The only other known example of such an oddly angled orbit was Pluto, until its demotion to dwarf planet status.

唯一的另一个已知的以如此奇怪的角度运行的例子是冥王星，直到它降级为矮行星。

A recently-discovered dwarf planet, named Sedna, has an extra-long and usual elliptical orbit around the Sun.

一颗近期被发现的褐矮星“赛德娜”(Sedna)有一个超长的椭圆形的绕太阳的轨道。

Pluto, now classed as a dwarf planet, is so small and so distant that its surface has been a mystery to astronomers.

现在归类于矮行星的冥王星是那么小，那么远，对天文学家来说，其表面一直是个谜。

In 1930 astronomer Clyde Tombaugh discovered the dwarf planet Pluto while looking at photographs of the night sky.

1930年，天文学家克莱德·汤博在研究夜空照片的时候发现了矮行星冥王星。

Once classified as a true planet, icy Pluto is now considered one of the more than 40 dwarf planets in our solar system.

它曾一度被划归为行星，冰冷的冥王星目前被认为是我们太阳系的40多个矮行星之一。

In 1930, astronomer Clyde Tombaugh discovered the dwarf planet Pluto while looking at photographs of the night sky.

1930年天文学家克莱德·汤博就是研究了夜空的图片后发现了矮行星冥王星。

Indeed so could Ceres, a dwarf planet in the asteroid belt, and Pluto, a dwarf planet even farther off than Neptune.

谷神星，小卫星带上的一颗矮卫星，以及比海王星更加远的矮卫星——冥王星，也可能拥有海洋。

That's when astronomers turned up a handful of large trans-Neptunian objects that led to the creation of the "dwarf planet" category.

当时科学家们连续发现了不少海王星外的大型星体，继而产生了“矮行星”这一分类。

Of course, after Pluto's official demotion from planet to dwarf planet, the mission can no longer claim to be exploring the final planet frontier.

当然，自从冥王星被官方从大行星降格为矮行星之后，这个项目也无法被称做对于行星前沿的探索。

Eris is real, but it is a dwarf planet similar to Pluto that will remain in the outer solar system; the closest it can come to Earth is about 4 billion miles.

行星厄里斯是真的，但它是一个和冥王星类似的矮行星，将继续待在太阳系外围；它最接近地球的位置有大约40亿英里。

According to IAU, a "dwarf planet" should have an orbit around the Sun. It will not have a clear neighborhood around its orbit, and must not be a satellite.

根据国际天文学联合会的定义，“矮行星”应该有一条环绕太阳的轨道，它不能清除其轨道附近的其它天体，而且不是一颗卫星。

Janhunen says it would take a 440-pound (200-kilogram) spacecraft using an electric sail less than five years to travel between Earth and dwarf planet Pluto.

Janhunen说，采用该电驱动帆作为动力，440磅(200千克)重的航天器从地球飞到冥王星所需时间少于5年。

The IAU further resolves that Pluto is a dwarf planet by the above definition and is recognized as the prototype of a new category of Trans-Neptunian Objects.

根据上述的定义，国际天文联会进一步决定将冥王星拨归为矮行星，并成为其中一类海王星外天体的原型。

Hubble recently showed a fourth moon orbiting Pluto. Astronomers temporarily named it P4. The moon is the smallest to be discovered around the icy dwarf planet.

哈勃太空望远镜最近发现了第四颗绕行冥王星的卫星。天文学家们暂时把它命名为P4。该是迄今为止发现的围绕这颗冰雪覆盖的矮行星的最小的卫星。

Hubble recently showed a fourth moon orbiting Pluto. Astronomers temporarily named it P4. The moon is the smallest to be discovered around the icy dwarf planet.

哈勃望远镜最近发现了冥王星第4颗卫星，天文学家暂时称之为冥卫四(P 4)，它是环绕冥王星的最小的卫星。