当他教他们天文学的时候，他不仅仅教了行星的名字，还用利用这些名字来教神话学。
When he was teaching them astronomy, he didn't just teach them the names of the planets—he used it as a way to teach mythology.
然而如果这颗行星处于很好的位置，天文学家会寻找三样关键的东西：水、空气和岩石。
However, if the planet is in a good position, astronomers look for three key things: water, air and rock.
例如，希腊天文学家对行星运动进行了非常出色和精确的观察，但这些观察暴露了一点小问题。
For example, Greek astronomers made excellent, very accurate observations of the movements of the planets, but the observations revealed a bit of a problem.
现在，许多天文学家正在寻找新的行星和未来人类居住的新地方。
Now, many astronomers are looking for new planets and new places of humans to live in the future.
天文学家怀疑成对的行星也参与了这种弹弓活动，使它们处于不规则的椭圆轨道上。
Astronomers suspect that pairs of planets also engage in this slingshot activity, leaving them in disturbed, elliptical orbits.
当天文学家发现了这颗恒星，他们就会观察它周围的行星。
When astronomers have found the star, they look at the planets around it.
近年来，天文学家已经发现了近400颗新的有行星的恒星。
In recent years, astronomers have found nearly 400 new planets with stars.
经过多年的仔细研究，天文学家发现了一颗与地球相似的行星。
After many years of scrutinizing, astronomers have found a planet that is similar to the Earth.
我们太阳系的有序特性使大多数天文学家得出结论，这些行星基本上在同一时间形成，且物质来源和太阳的一样。
The orderly nature of our solar system leads most astronomers to conclude that the planets formed at essentially the same time and from the same material as the Sun.
天文学家在距离地球不远处发现一颗小行星，它与地球在同一轨道上围绕太阳运行。
Astronomers have detected an asteroid not far from Earth, moving in the same orbit around the Sun.
天文学家试图通过估计太阳质量能产生多少必需的光来解释这些行星上的液态水。
Astronomers tried to estimate what solar mass could produce the required luminosity to explain liquid water on these planets.
银河系中最少有500亿的外行星，这个天文学估算听起来怎么样？
How's this for an astronomical estimate? There are at least 50 billion exoplanets in our galaxy.
下一步天文学家试图找到这颗钻石行星是否有行星环。
The next step for astronomers is to find out if the diamond planet has rings.
即使在这样较小的质量下，鉴于恒星和行星诞生的环境的不同，许多天文学家依然会将它划分为小质量恒星而不是行星。
Even at this smaller mass, however, many astronomers would still classify it as a low mass star rather than a planet, since the circumstances of birth for stars and planets differ.
小行星对地球的威胁最大，然而，天文学家说，在这一点上很难说木星的作用是好是坏。
Asteroids pose the greatest danger of all to Earth, however, astronomers say, and here Jupiter's influence is hardly assuring.
他认为，人类运用雷达天文学探测小行星和金星等天体，早已经发射出可以被外星智慧生物接收到的信号。
He argues that radar astronomy, which is used to probe things like asteroids and the surface of Venus, already gives off signals that could be picked up by aliens.
首次发现太阳系以外的行星后不到20年，天文学家们正准备打造一个重要的里程碑——第500个外星世界的发现。
Less than 20 years after first finding a planet beyond our solar system, astronomers are poised to hit a big milestone - the discovery of alien world no. 500.
为了研究系外行星，天文学家必须非常有创造性。
In order to study exoplanets, astronomers have had to be quite inventive.
业余天文学家们也已参与寻找有趣的小行星和观测太阳风暴。
They have also looked for interesting asteroids, and kept an eye out for solar storms.
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.
在荷兰天文学家克里斯蒂安·惠更斯发现土星环以及第一颗已知土星卫星——土卫六“泰坦”之后，这颗行星逐渐成为天文学家的关注焦点。
The planet was only just beginning to come into focus, in the metaphorical sense: The Dutch astronomer Christiaan Huygens had just recently revealed Saturn's rings and its first known moon, Titan.
但是经过更多的观察和一数字演算之后，天文学家注意到这个行星在2029年撞击地球的可能性微乎其微。
A few additional observations and some number-crunching later, astronomers noted that the chance of the planet-killer hitting Earth in 2029 was nearly zilch.
通过测量星光金额行星块，天文学家还可以计算出它是相对于大明星。
By measuring the amount of starlight a planet blocks, astronomers can also calculate how big it is relative to the star.
天文学家们猜想这颗行星存在于一个绕着恒星满是尘埃的圆盘中的一个大洞中。
Astronomers inferred the planet's presence from an enormous hole in the dusty disk that girdles the star.
但是撇开这些争议，冥王星始终是一颗迷人的行星，无论是天文学家还是公众都迫不及待想要一窥其究竟。
But regardless of the controversy, Pluto remains an intriguing object that astronomers and the public alike can't wait to learn more about.
天文学家早就认为，几大行星的轨道是可以预测的。
Astronomers had thought that the orbits of the planets were predictable.
但测量行星的质量，天文学家通常还需要使用地球上最大的天文望远镜，来测算径向速度的耗时。
But to get the planet's mass, astronomers normally need to follow up with time-consuming radial velocity observations at some of the planet's biggest telescopes.
你可能会想，天文学已经够复杂了，天文学家为什么还给系外行星取些把人搞晕的名字？
Astronomy is complicated enough as it is, so you might wonder why astronomers give exoplanets such confusing names.
搜寻行星时通常把年轻的恒星排除在外，因为它们有强烈的磁场，会产生包括耀斑在内的恒星磁活动，这使得天文学家很难分辨行星和活动信号。
Young stars are usually excluded from planet searches because they have intense magnetic fields that generate a range of phenomena known collectively as stellar activity, including flares and spots.
第一颗系外行星于1995年载入天文记录，到目前为止，天文学家们确认了515颗戏外行星的探测，其中大部分都是类似木星的巨行星。
The first exoplanet was catalogued in 1995 and astronomers have so far confirmed the detection of 515. Most are giant planets thought to resemble Jupiter.
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