VOA慢速英语2019 天文学家绘制了新的银河系地图（在线收听）

Astronomers Make New Map of the Milky Way

Astronomers have created the most correct map yet of the Milky Way – the part of space that contains our sun, solar system and more than 100 billion stars.Researchers made the three-dimensional map by measuring the distance from the sun to thousands of big, brightly shining stars.

天文学家绘制出了迄今为止最为精确的银河系地图——银河系是包含我们的太阳、太阳系和1000多亿颗恒星的空间。研究人员通过测量从太阳到数千颗明亮的大恒星的距离，绘制出了这幅三维地图。

They found that the shape of the Milky Way is not flat, but twisted.It is made of four major spiral arms and a bar-shaped main area.Their findings were published in the journal Science.

他们发现银河系的形状不是扁平的，而是扭曲的。它由四个大的螺旋型枝节和一个条状的核心区域组成。他们的发现发表在《科学》杂志上。

Andrzej Udalski is an astronomer at the University of Warsaw and a co-author of the study.He said that, for the first time, our whole galaxy was mapped from edge to edge using real distances.

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。他说:“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。”

Until now, the understanding of the galaxy’s shape had been based on indirect measurements.

到目前为止，人类对星系形状的了解都是建立在间接测量的基础上的。 

For the new map, researchers measured the distance from the sun to some 2,400 stars spread throughout the galaxy.The stars are called “Cepheid variables.”

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

Dorota Skowron is also a University of Warsaw astronomer and a co-author of the study.Skowron explained that Cepheids are giant stars that are far brighter than the sun.They are also “relatively young” – less than 400 million years old.This means that they are located near their birthplaces.

多洛塔·斯考伦也是华沙大学的天文学家和该研究报告的合著者。斯考伦解释说，造父变星是比太阳明亮得多的超巨星。它们形成的时间相对较短，不到4亿年，这意味着它们位于其发源地附近。

The astronomers studied the Cepheids using the Warsaw Telescope located in the Chilean Andes.Because the stars pulsate at regular times, researchers could see them through the galaxy’s clouds of dust.

天文学家使用位于智利安第斯山脉的华沙望远镜研究造父变星。由于恒星发生脉动是有规律的，研究人员可以通过星系的星际尘埃云看到它们。

The final map showed that the galaxy’s shape changes from place to place.It becomes increasingly thick as it moves away from the center.

最后一张地图显示，星系的形状各处不一。距离星系中心越远处越厚。 

Researchers also found that the galaxy’s disk has a diameter of about 140,000 light years.Each light year is about 9 trillion kilometers.

研究人员还发现，银河系星系盘的直径约为14万光年。每光年大约有9万亿公里。