第1881期:Scientists Observe Gravitational Waves Linked to Black Holes

Scientists say that, for the first time, they have observed gravitational waves caused by black holes and other huge space objects moving through the universe. A group of international scientists using radio telescopes in North America, Europe, China, India and Australia made the observation. The existence of gravitational waves was first predicted more than 100 years ago by physicist Albert Einstein as part of his General Theory of Relativity. Einstein’s theory proposed that gravity is caused by a curving of space and time.

科学家表示，他们首次观测到黑洞和其他巨大太空物体在宇宙中移动引起的引力波。一组国际科学家使用北美、欧洲、中国、印度和澳大利亚的射电望远镜进行了观测。一百多年前，物理学家阿尔伯特·爱因斯坦在其广义相对论中首次预言了引力波的存在。 爱因斯坦的理论提出，引力是由空间和时间的弯曲引起的。

Scientists believe that, as gravitational waves travel through space, they press against and stretch everything they pass through. But researchers have struggled for many years to find solid evidence of the waves. In the 1970s, researchers found indirect proof by studying the motion of two crashing stars. That work was honored as part of the 1993 Nobel Prize in physics. Then, in 2016, astronomers announced they had detected the first direct evidence of gravitational waves. That evidence came from an American-based research project known as the Laser Interferometer Gravitational-Wave Observatory, or LIGO. The LIGO project used ground-based telescope instruments to detect a gravitational wave produced when two black holes crashed into each other about 1.3 billion light years from Earth.

科学家认为，当引力波穿过太空时，它们会挤压并拉伸所经过的所有物体。 但研究人员多年来一直在努力寻找海浪确实存在的证据。 20 世纪 70 年代，研究人员通过研究两颗碰撞恒星的运动找到了间接证据。 这项工作被授予 1993 年诺贝尔物理学奖。然后，在 2016 年，天文学家宣布他们发现了引力波的第一个直接证据。 这些证据来自一个名为激光干涉仪引力波天文台（LIGO）的美国研究项目。 LIGO 项目使用地面望远镜仪器来探测距离地球约 13 亿光年的两个黑洞相互碰撞时产生的引力波。

But the LIGO effort was only able to pick up waves at high frequencies. In the latest research, scientists were attempting to find low-frequency waves as a way to confirm gravitational wave signals.↳ The researchers said they successfully discovered such signals using about 15 years of data from a project called NANOGrav. This project has long used telescopes across North America to search for low-frequency gravitational waves. The results were recently published in a study in The Astrophysical Journal of Letters.

但 LIGO 的努力只能拾取高频波。 在最新的研究中，科学家们试图寻找低频波来确认引力波信号。研究人员表示，他们利用 NANOGrav 项目约 15 年的数据成功发现了此类信号。 该项目长期以来一直使用北美各地的望远镜来寻找低频引力波。 该结果最近发表在《天体物理学文学杂志》的一项研究中。

The research involved scientists aiming a series of radio telescopes at dead stars called pulsars. The pulsars send out radio wave signals as they spin around in space. These signals are so predictable that scientists know exactly when the radio waves are supposed to arrive on Earth. The pulsars are like “a perfectly regular clock ticking away far out in space,” said NANOGrav member Sarah Vigeland. She is an astrophysicist at the University of Wisconsin-Milwaukee. But gravitational waves can affect the distance between Earth and the pulsars, which can change the signal activity.

这项研究涉及科学家将一系列射电望远镜瞄准称为脉冲星的死亡恒星。脉冲星在太空中旋转时发出无线电波信号。这些信号是如此可预测，以至于科学家们确切地知道无线电波何时到达地球。 NANOGrav 成员莎拉·维格兰 (Sarah Vigeland) 表示，脉冲星就像“一个在遥远的太空中滴答作响的完全规则的时钟”。她是威斯康星大学密尔沃基分校的天体物理学家。但引力波会影响地球和脉冲星之间的距离，从而改变信号活动。