It feels like every time astronomers even look at a star these days, they find a planet or two in orbit around it. They’ve confirmed about 3500 planets in all, with thousands more awaiting confirmation. The planets range from about the mass of the Moon to many times the mass of Jupiter, the largest planet in the solar system. Some are quite close to their parent stars, while others are far away. And some orbit a single star, while others have two suns in their sky — or even three.
近来，好像只要天文学家们朝一颗恒星看上一眼，就能在其轨道上发现一两颗行星。他们已经确认了总共大约3500颗行星，还有数千颗正等待确认。行星的质量范围从月亮那么大到数倍于太阳系最大的行星——木星的质量。有些离它们的恒星很近，有些却离得很远。有些绕唯一的恒星运行，而另外一些则有两颗甚至三颗太阳高悬于天空。 One amazing thing about these discoveries is that, in an era of giant telescopes, most of the exoplanets were found with small telescopes.
关于这些发现，一件令人惊异的事情是：在这个巨型望远镜的时代，绝大多数的系外行星都是用小望远镜找到的。 Most of the planets were discovered with Kepler Space Telescope. The spacecraft looks for a small dip in a star’s light caused by a planet passing across its disk. And it does so with a main mirror that measures just three feet across — quite small by modern research standards.
大部分系外行星是由开普勒太空望远镜发现的。该航天器寻找行星经过恒星圆面时少许变暗的星光。而它是依靠一个口径只有三英尺的主镜完成这些的——用现代研究的标准看，三英尺口径确实非常小了。 Many ground-based planet searches are done with even smaller telescopes, which devote all their time to hunting planets. A robotic network known as HAT, for example, has discovered almost 60 planets with telescopes that consist of 200-millimeter camera lenses. And a telescope known as KELT-North, which uses an 80-millimeter lens, has discovered four confirmed planets.
很多基于地面的行星研究甚至是通过更小的、专门狩猎行星的望远镜完成的。比如，一个被称为HAT的自动监测网已经发现了大约60颗行星，监测网由多架口径20厘米望远镜组成。一架被称为KELT-North的望远镜，运用8厘米的镜片发现了4颗已被确定的行星。 These little telescopes are helping make some big discoveries about worlds in other star systems.