按照它们与太阳的距离排列，这些行星分别是水星、金星、地球、火星、木星、土星、天王星、海王星和冥王星。
The planets, in order of their distance from the Sun, are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto.
木星、土星、天王星和海王星。这些都是气体行星，是太阳系的四个重量级。但曾经存在第五个行星吗？
Jupiter, Saturn, Uranus, and Neptune. Those are the gas giants, the four heavyweights of the solar system. But was there once a fifth?
最大的类地行星地球的直径仅仅是最小的类木行星海王星的四分之一，而且地球的质量仅仅是其质量的十七分之一。
The largest terrestrial planet, Earth has a diameter only one quarter as great as the diameter of the smallest Jovian planet, Neptune, and its mass is only one seventeenth as great.
穿过小行星带继续前进，我们进入了气体巨行星区域：木星、土星、天王星、海王星，所有这些都使地球看起来像个侏儒。
Moving on through the asteroid belt we enter the realms of the gas giant planets: Jupiter, Saturn, Uranus, and Neptune, all of which dwarf the Earth.
我们的地球和其他行星——水星、金星、火星、木星、土星、天王星、海王星、冥王星一起围绕着太阳旋转，构成所谓的太阳系。
Our planet Earth, together with other planets, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto revolve around our Sun in what is called our Solar system.
这个新模型追踪了海王星轨道外数无数个微小物体的运行轨迹，它可以帮助天文学家计算出其他星系尘埃盘中行星的特性。
The new model, which tracks thousands of tiny particles beyond the orbit of Neptune, could help astronomers work out the properties of planets in other stars' dust disks.
余下的八大行星为：水星、金星、地球、火星、木星、土星、天王星和海王星。
Eight planets officially remain: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
根据自己的研究，比克福德预测其他的行星包括木星、土星、海王星和天王星也应该有类似的反质子带。
Bickford's own research predicts that other planets, including Jupiter, Saturn, Neptune, and Uranus, should have similar antiproton belts.
除了数千个一起与木星围绕太阳运行的特洛伊小行星之外，天文学家们发现了几个随着海王星和火星一起围绕太阳运转的行星。2010TK 7对地球不会造成威胁。
Besides the thousands of Trojans that co-orbit the sun with Jupiter, astronomers have discovered a handful that co-orbit the sun with Neptune and Mars. 2010 TK7 isn't a threat to Earth.
厄里斯和许多其他在海王星轨道绕着太阳转动的天体，又该不该是行星呢？
Should Eris, and many other objects circling the sun beyond Neptune's orbit?
如图所示，我们太阳系中的气态巨行星——木星、土星、天王星、海王星——大部分是由氢构成的。图片来自。
As indicated in the graphic, the gas giant planets of our solar system - Jupiter, Saturn, Uranus and Neptune - are mostly composed of hydrogen. Image courtesy of NASA.
在它的事件视界，即其边界，没有任何东西可以逃脱这头巨兽的引力，甚至连光也不行。 其引力相当于位于我们太阳系最外层行星轨道的海王星的四倍。
Its event horizon--theboundary at which nothing, not even light, can escape the monster’s gravitationalpull--is four times as large as the orbit of Neptune,our sun’s outermost planetary satellite.
l利用牛顿的引力计算公式，天文学家发现了许多过去不知道的恒星和行星，其中包括海王星和冥王星。这是根据它们对其他太空物体的引力作用测算出来的。
Using Newton's formula for gravity, astronomers have detected previously unknown stars and planets, including Neptune and Pluto, from the effect of their gravity on other space objects.
“如果这个最大的未被发现的‘同伴’只有海王星那么大，或者更小，大部分行星科学家都不会感到惊喜，但是如果是木星那么大的暗星体，那将是一个惊喜，”马泰赛告诉SPACE.com太空网。
'Most planetary scientists would not be surprised if the largest undiscovered companion was Neptune-sized or smaller, but a Jupiter-mass object would be a surprise, ' Matese told SPACE.com
因此，天文学家认为MOA-192 b 不会像地球这样气候宜人，而是像海王星一样，是一个冰冷的气态行星。虽然要在这颗行星上安家太冷了，但是它给予我们希望，或许地球这样尺寸的较小行星还是挺多的。
And while the planet is likely too chilly to make a good home, it gives us hope that smaller, Earth-sized planets may be abundant.
木星，土星，天王星和海王星。这些都是气体行星，太阳系的四个重量级。但曾经存在第五个行星吗？
Jupiter, Saturn, Uranus and Neptune. Those are the gas giants, the four heavyweights of the solar system. But was there once a fifth?
经过长达六年的观察，科学家发现有五颗行星的质量是地球的13-25倍，或者说，与海王星的质量差不多，它们围绕恒星的旋转周期在6到600天之间。
Six years of observations revealed the presence of five planets between 13 and 25 times the mass of Earth, or about the mass of Neptune, that orbit the parent star once every 6 to 600 days.
虽然海王星不属于肉眼可见的行星，这个月在美国早起的人们便可以用望远镜看到海王星——如果你知道往哪里看的话。
Although Neptune is not among the planets visible to the naked eye, early birds with telescopes in the United States can spot Neptune this month-if you know where to look.
正因为了有这条定律，我们才能得知例如金星这样离日相对较近的行星的公转周期要短于离日较远的行星，例如海王星。
Thanks to this law, we know that a planet relatively close to the sun, like Venus, has a far briefer orbital period than a distant planet, such as Neptune.
这颗行星最终以罗马神话中的海神命名，称为海王星。
The planet was eventually named Neptune, after the Roman god of the sea.
譬如说今日的(左上图)，气体巨型星海王星的重力通过对轨道就在行星们不远处的柯伊伯带的结冰尘埃和残骸拉扯制造出数个缺口。
Today (top left), for example, the gravity of the gas giant Neptune creates gaps by tugging at the icy dust and debris of the Kuiper belt, which orbits just beyond the planets.
它是唯一的一颗已知的“超级地球”外行星-质量在地球与海王星之间-被证实了有大气。
It is the only known "Super-Earth" exoplanet-worlds that have masses between Earth and Neptune-with a confirmed atmosphere.
气体巨行星是像木星或海王星一类包含大量的气体物质的大的行星。
A large planet, like Jupiter or Neptune, that is composed largely of gaseous material.
事实上，大约三分之二的质量小于海王星的已知系外行星是由HARPS单独检测到的。
In fact, HARPS alone has detected about two-thirds of all known exoplanets with masses less than that of Neptune.
到那时我们太阳系最亮的两颗行星——金星和木星将密切会合，天王星和海王星将发出绿光，不过需要一架好的双筒望远镜才能看到。
That's when the two brightest planets in our own solar system, Venus and Jupiter, will almost unite.Uranus and Neptune will be shining green but will need a good binocular to be seen.
到那时我们太阳系最亮的两颗行星——金星和木星将密切会合，天王星和海王星将发出绿光，不过需要一架好的双筒望远镜才能看到。
That's when the two brightest planets in our own solar system, Venus and Jupiter, will almost unite. Uranus and Neptune will be shining green but will need a good binocular to be seen.
有四个比地球的太阳系中的最大行星木星稍微大一点。还有一个和第四大行星海王星大小差不多。
Four are a little bigger than Jupiter, the largest planet in the Earth's solar system, and one is about the size of Neptune, the fourth-largest.
只有少数星球在大小上接近于我们所居住的这颗行星，而且也只有这其中的少数可能像地球一样呈岩石状，而不是像木星那样呈气态状或海王星那样的冰状。
Just a handful are close in size to our planet, and only a few of those may be rocky like the Earth, rather than gaseous like Jupiter or icy like Neptune.
发现这颗行星同样一组天文学家早些时候也发现另一颗行星，该行星同海王星类似，是一颗巨大的气体行星，围绕恒星运转的周期为5.4天。
The same team of astronomers who discovered it had earlier found another planet, this time a gaseous giant similar to Neptune, orbiting the same star every 5.4 days.
之外是是四颗气态巨行星——木星、土星、天王星和海王星。
After that are four gas giants - Jupiter, Saturn, Uranus and Neptune.
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