VOA慢速英语2017 新发现的太阳系与我们的太阳系相匹配（在线收听）

Newly Discovered Solar System Matches Our Own

The American space agency NASA and the technology company Google have identified an eighth planet in a faraway solar system.

美国宇航局和谷歌科技公司已经发现了一个遥远的类太阳系中的第八颗行星。

That solar system now has exactly the same number of planets as our own.

这个类太阳系现在跟我们太阳系拥有数量相同的行星。

Machines made the surprising discovery, not human researchers.

取得这一惊人发现的是机器，而不是人类研究员。

NASA and Google representatives made a joint announcement about the discovery on December 14.

美国宇航局和谷歌代表于12月14日共同宣布了这一发现。

The newly discovered planet orbits the star known as Kepler-90. The system is about 2,545 light-years away. A light-year is about 9.5 trillion kilometers.

这颗新发现的行星围绕着被称之为开普勒90的恒星运转。该星系位于大约2545光年之外，一光年大约是9.5万亿公里。

Researchers have named the planet Kepler-90i. Like Earth, Kepler-90i is the third farthest planet from its sun.

研究人员已经将这颗行星命名为开普勒90i。跟地球一样，开普勒90i是距它的太阳最远的第三颗行星。

However, Kepler-90i is much closer to its sun. It only takes the planet 14 days to orbit Kepler-90. So, its surface is much warmer -- 427 degrees Celsius. In fact, all the planets in the Kepler-90 solar system orbit closer to their sun than Earth does to our sun.

然而，开普勒90i更靠近该系统中的太阳，它围绕开普勒90运转一圈只需要14天时间。所以它的表面温度更高，达到了427摄氏度。实际上，开普勒90太阳系轨道上所有行星跟它们的太阳之间的距离都要小于我们地球跟太阳的距离。

So far, this is the only other eight-planet solar system that researchers have found. Eight is the largest number of planets ever observed around a single sun.

这是研究人员迄今为止发现的唯一的另一个八行星太阳系。有史以来观测到的围绕单独一个太阳运转的行星最多就是8颗。

Our solar system had nine planets up until 2006, when the International Astronomical Union decided Pluto did not meet the requirements to be considered a planet. Instead, the group renamed it a dwarf planet.

我们太阳系在2006年以前曾经有过9颗行星，当时国际天文联合会判定冥王星没有达到行星的认定标准。相反，该组织将它重新命名为矮行星。

But some astronomers believe there could be a large ninth planet far off in our solar system. They call it Planet X, and believe it is the size of Neptune.

但是一些天文学家认为，在我们太阳系中的远端可能会有第九颗较大的行星。它们将其称之为X行星，并认为它有海王星那么大。

Researchers also believe there could be nine or more planets in the Kepler-90 solar system.

研究人员还认为开普勒90星系可能会有第九颗甚至更多行星。

Google used data from NASA’s special planet-hunting device, called the Kepler Space Telescope, to locate Kepler-90i. The company used the data to develop a computer program with machine learning. This means it can learn and improve itself without a programmer telling it to do so. The program carefully studies planetary signals that are so weak it would take humans years to examine them.

谷歌公司使用了来自美国宇航局的特殊行星搜索设备开普勒太空望远镜的数据来确定开普勒90i行星的位置。该公司利用这些数据开发了具备机器学习能力的计算机程序。这意味着它可以无需程序员引导自我学习并提升。该程序仔细研究了人类可能需要花费数年时间检查的微弱行星信号。

Christopher Shallue is a senior software engineer at Google in Mountain View, California. He said, “This is a really exciting discovery, and we consider it to be a successful proof of concept to be using neural networks to identify planets, even in … situations where the signals are very weak.”

克里斯托弗·谢纽（Christopher Shallue）是加州山景城谷歌公司的一名高级软件工程师。他说：“这是一项非常令人兴奋的发现，我们认为它成功证明了利用神经网络识别行星的这一概念，哪怕行星信号非常微弱。”

NASA astrophysicist and Kepler project scientist Jessie Dotson said she is “so excited to see where this goes next.”

美国宇航局和开普勒项目科学家杰西·朵森（Jessie Dotson）表示她很高兴看到它下一步的发展方向。

Shallue partnered with astronomer Andrew Vanderburg of the University of Texas at Austin to develop this machine-learning program. The two trained a computer to identify planets beyond our solar system. To do so, it used observations of the minor changes in the brightness of stars when planets passed in front of them that the Kepler Space Telescope had recorded.

谢纽和德克萨斯大学奥斯丁分校的天文学家安德鲁·范德伯格（Andrew Vanderburg）合作开发了这个机器学习程序。他们两人训练了一台电脑来识别太阳系以外的行星。为了实现这点，它利用了开普勒太空望远镜记录下的恒星在行星经过时亮度细微变化的观测结果。

Shallue and Vanderburg plan to continue hunting for new planets. They plan to use the program to examine the more than 150,000 stars that the Kepler Space Telescope has already identified.

谢纽和范德伯格计划继续寻找新的行星。他们计划使用该程序来检查开普勒太空望远镜已经发现的超过15万颗恒星。

So far, esearchers have confirmed the existence of more than 3,560 planets beyond our solar system. The Kepler Space Telescope, which launched in 2009, located about two-thirds of them.

到目前为止，研究人员已经证实了太阳系之外超过3560颗行星的存在。2009年发射的开普勒太空望远镜确定了其中三分之二的行星的位置。

Another 4,500 possible exoplanets await confirmation.

另外还有4500颗可能的系外行星有待确认。

I’m Pete Musto.

Words in This Story

solar system – n. a star and the planets that move around it

light-year(s) – n. a unit of distance equal to the distance that light travels in one year (about 5.88 trillion miles or 9.46 trillion kilometers

dwarf planet – n. an object in space that looks like a small planet but lacks special qualities that are required for it to be defined as such

data – n. facts or information used usually to calculate, analyze, or plan something

exciting – adj. causing feelings of interest and enthusiasm

concept – n. an idea of what something is or how it works

neural network(s) – n. a computer system designed to be similar to the human brain and nervous system

exoplanet(s) – n. a planet that is beyond our solar system