The stars are known as Cepheid variables.

些恒就是我们熟知造父变。

There are more than a thousand known cataclysmic variables.

已知激变变超过一千种。

The system belongs to a kind of binary star known as cataclysmic variable.

该系统属于一种被称为激变变双。

Only 12 or so have orbital periods below 75 minutes.

只有12种左右激变变拥有低于75分钟轨道周期。

Skowron explained that Cepheids are giant stars that are far brighter than the sun.

斯考伦解释说，造父变是比太阳明亮得多超巨。

They observed variable stars in the Andromeda Galaxy that allowed them to get the distance to the galaxy.

他们观测了仙女座系中变，使得他们能够到达系距离。

And it was, in fact, a variable star.

事上，它是一颗变。

" Var" here stands for " variable." Hubble had found a variable star in the Andromeda Nebula.

“Var”在里代表“变”。哈勃望远镜在仙女座云中发现了一颗变。

And since there were pulsating Cepheid stars whose actual distances we already knew, this let us build a cosmic measuring stick.

既然我们已经知道些有规律脉动造父变际距离，就给我们造出一把宇宙测量尺。

Now if two Cepheid stars are pulsating at the same rate, and one's dimmer than the other, that means one is actually farther away.

如果两个造父变以相同速率脉动，并且其中一个比另一个更加暗淡，就意味着更暗那个更远。

I observe from seven or eight till about two in the morning, with a view to my great work on variable stars.

我从七八点观察到凌晨两点左右， 以期完成我在变方面伟大工作。

If two Cepheid stars are pulsating at the same rate, and one's dimmer than the other, that means one is actually farther away.

如果两颗造父变以相同速率脉动，并且一颗比另一颗暗， 意味着一颗际上距离更远。

It was the review of a pamphlet by an American astronomer, in which the author announced a conclusive discovery with regard to variable stars.

那是一位美国天文学家对一本小册子评论，作者在书中宣布了关于变一个结论性发现。

She noticed that a type of star known as a Cepheid variable (after the constellation Cepheus, where it first was identified) pulsated with a regular rhythm-a kind of stellar heartbeat.

她注意到，有一种名叫造父变（以仙王座命名，第一颗造父变就是在那里发现）恒在有节奏地搏动——一种体“心跳”。

The approaches include looking at supernovae and variable stars in distant galaxies and measuring how fast they're receding, as well as how far away they are.

些方法包括观察遥远系中超新和变，并测量它们后退速度以及它们距离。

Actual variable stars do exist, but Tabby's Star doesn't fit that profile, it's what's known as an F-type main-sequence star, and shouldn't behave anything like this.

际变确存在， 但 Tabby's Star 不符合种情况，它是所谓 F 型主序， 不应该有样行为。

In the early 1900s, astronomer Henrietta Swan Leavitt realized a class of stars called Cepheids pulsate, bright and dim, and every Cepheid that pulsates at the same rate has the same brightness.

1900 年代早期，天文学家 Henrietta Swan Leavitt 发现一系列名为造父变，它们有规律地变亮和变暗，并且每个造父变以相同速率脉动就会有着相同亮度。

'I have made an amazing discovery in connexion with the variable stars, ' he exclaimed. 'It will excite the whole astronomical world, and the world outside but little less.

“我在变方面有了惊人发现，”他惊呼道。 “它会激发整个天文界兴奋，而外面世界却不会那么兴奋。”

'I am preparing a work on variable stars. There is one of these which I have exceptionally observed for several months, and on this my great theory is mainly based.

“我正在准备一部关于变作品。其中之一是我几个月来特别观察到，我伟大理论主要基于此。

These are called Cepheid variables, and they were critically important, because it was known that the time it took them to pulse was directly related to their luminosity, how much energy they emitted.

些被称为造父变，它们非常重要，因为我们知道它们产生脉冲时间与它们光度直接相关，也就是它们释放能量。