| 1. | Cepheid variable is the foundation of this ladder
，而造父变星便是这阶梯中不可或缺的其中一环。 |
| 2. | Cepheid variable stars are stars whose brightness changes at regular periods
造父变星是一种光线按规律周期发生变化的恒星。 |
| 3. | This makes space telescope invaluable for identifying a rare class of pulsating stars , called cepheid variable stars embedded within m100 ' s spiral arms
这对于从m100的旋臂中分辨出暗藏的造父变星有着莫大价值。 |
| 4. | One of the key project of hubble s telescope is to gauge as many cepheid variables as possible in more distant galaxies up to 65 millions light years
哈勃太空望远镜的一个重点计划，就是要测量更多更远星系中的造父变星远达 |
| 5. | Since delta cephei was one of the earliest members of a special kind of variables being discovered , all variables in this family are called cepheid variables or simply cepheids
星的中国名称为造父一，由于它最早被发现的一种新变星类别，所以这类变星皆称为造父变星。 |
| 6. | Cepheid variables are dimmer than the type i supernova . as a result , the supernova allows us to measure the distances of galaxies further away , but it happens much less often
I型超新星比造父变星光亮，所以能够量度更遥远星系的距离，唯一缺点是不经常有i型超新星爆发。 |
| 7. | Astronomers made observations of cepheid variable stars [ pictured above ] ? pulsating stars used to measure vast distances ? in the virgo and other clusters to establish the expansion rate and the universe ' s age
天文学家用哈勃观测到仙女星座和其它星群中的造父变星(如图) ，以确定宇宙的膨胀速度和宇宙的年龄。 |
| 8. | The longer the period , the brighter the star is . thus , by measuring the period of a cepheid variable , we know its absolute magnitude , hence , we can tell how far it is away by comparing with its apparent magnitude
所以，只要知道某一造父变星的周期，我们便可得知它的绝对星等，只要和它的视星等作比较，便可以求得它和我们的距离。 |
| 9. | We have to use some other methods to measure the luminosity or equivalently the absolute magnitude of the cepheid variable . since we can readily measure the apparent magnitude of a cepheid variable , to measure the luminosity means measuring the distance . we use some distance measurement methods , for example , parallax , to determine the relation
要弄清这个关系，我们要知道不同造父变星的光度和光变周期数据，量度光变周期当然不是问题，但要得知一颗恒星的光度，我们首先要得知它的距离，这时便须借助好像视差法等其他量度天体距离的方法。 |
| 10. | Except those celestial objects of several hundred light years , astronomers rely primarily on cepheid variables for measuring distances of celestial objects . using ground telescopes to gauge cepheid variables enable us to directly measure celestial objects within 20 to 30 millions light years . for more distant stars , other methods have to be used
除了几百光年内的星体外，天文学家很主要倚靠测量造父变星来计算天体的距离，利用地面望远镜测量造父变星，可直接给出约二三千万光年内星体的距离，而对于更遥远的星体，天文学家便要借助其他方法，但这些方法还是需要利用造父变星来作校正。 |
