银河系居然是弯的!

Astronomers have created the most precise map to date of the Milky Way by tracking thousands of big pulsating stars spread throughout the galaxy, demonstrating that its disk of myriad stars is not flat but dramatically warped and twisted in shape.

天文学家通过追踪遍布银河系的数千颗大的脉动变星，绘制出了迄今为止最精确的银河系地图。从地图上看，由无数恒星组成的星系盘并非扁平，而很明显是弯曲的、扭曲的。

The researchers on Thursday unveiled a three-dimensional map of the Milky Way - home to more than 100 billion stars including our sun - providing a comprehensive chart of its structure: a stellar disk comprised of four major spiral arms and a bar-shaped core region.

研究人员于上周四公布了一张银河系的三维地图，其中包括太阳在内共有1000多亿颗恒星。这张地图全面展示了银河系结构：由四个大的螺旋型枝节和一个条状的核心区域组成的星系盘。

'For the first time, our whole galaxy - from edge to edge of the disk - was mapped using real, precise distances,' said University of Warsaw astronomer Andrzej Udalski, co-author of the study published in the journal Science.

研究报告的作者之一、华沙大学天文学家安德烈·乌达尔斯基说：“从星系盘的一端到另一端，我们第一次使用真实、精确的距离绘制了整个银河系的地图。”研究报告发表在《科学》杂志上。

Until now, the understanding of the galaxy's shape had been based upon indirect measurements of celestial landmarks within the Milky Way and inferences from structures observed in other galaxies populating the universe.

到目前为止，人类对星系形状的理解是基于对银河系内天体标志的间接测量，以及对宇宙中其他星系结构的推断。

The new map was formulated using precise measurements of the distance from the sun to 2,400 stars called 'Cepheid variables' scattered throughout the galaxy.

这幅新地图是通过精确测量散布在银河系中的2400颗“造父变星”与太阳之间的距离而绘制的。

'Cepheids are ideal to study the Milky Way for several reasons,' added University of Warsaw astronomer and study co-author Dorota Skowron.

“造父变星是研究银河系的理想选择，原因有很多，”华沙大学天文学家、研究报告的合著者多洛塔·斯考伦补充道。

'Cepheid variables are bright supergiant stars and they are 100 to 10,000 times more luminous than the sun, so we can detect them on the outskirts of our galaxy. They are relatively young - younger than 400 million years - so we can find them near their birthplaces.'

“造父变星是明亮的超巨星，其亮度是太阳的100到一万倍，所以我们可以在银河系的外围探测到它们。它们形成的时间相对较短，不到4亿年，所以可以在其发源地附近找到它们。”

The astronomers tracked the Cepheids using the Warsaw Telescope located in the Chilean Andes.

天文学家使用位于智利安第斯山脉的华沙望远镜追踪造父变星。

These stars pulsate at regular intervals and can be seen through the galaxy's immense clouds of interstellar dust that can make dimmer stellar bodies hard to spot.

这些恒星有规律地发生脉动，可以透过星系中巨大的星际尘埃云看到，这些尘埃云会使较暗的恒星体很难被发现。

The map showed that the galaxy's disk, far from flat, is significantly warped and varies in thickness from place to place, with increasing thickness measured further from the galactic center.

这张地图显示，银河系的星系盘远非平面状，而明显是弯曲的，且各处厚度不一，距离星系中心越远处越厚。

The disk boasts a diameter of about 14,000 light years. Each light year is about 6 trillion miles (9 trillion km).

银河系星系盘的直径约为1.4万光年。每光年大约有6万亿英里（9万亿公里）。

The Milky Way began to form relatively soon after the Big Bang explosion that marked the beginning of the universe some 13.8 billion years ago.

银河系是在大约138亿年前宇宙大爆炸后不久开始形成的。宇宙大爆炸标志着宇宙的起源。

The sun, located roughly 26,000 light years from the supermassive black hole residing at the center of the galaxy, formed about 4.5 billion years ago.

太阳形成于大约45亿年前，距离位于星系中心的超大质量黑洞约2.6万光年。