『新东方在线托福听力』为托福考生准备了ETS托福TPO/【学术讲座】#19听力练习：What is the main topic of the talk?原文题目答案解析，TPO/【学术讲座】#19听力原文范文音频翻译。

托福TPO/【学术讲座】#19听力原文What is the main topic of the talk?【新东方在线】

暗物质是一种既不发光、也不吸收或反射光的物质，因此目前的仪器无法观测到它。
尽管无法直接观测，但据信它约占宇宙质能含量的27%。

Dark matter is a type of matter that doesn’t emit, absorb, or reflect light, making it invisible to current instruments.Despite being unobservabl directly, it’s believed to make up about 27 percent of the universe’s mass-energy content.

科学家如何知道暗物质的存在呢？
其实，星系中的所有恒星都围绕星系中心旋转。

How do scientists know dark matter exists?
Well, all the stars in a galaxy rotate around the center of their galaxy.

根据基础物理学原理，恒星距离星系中心越远，其旋转速度应该越慢。
然而，观测结果显示，星系外围区域的恒星旋转速度却出乎意料地快。

According to basic physics, the farther a star is from the center of a galaxy, the slower it should rotate.
However, observations show that stars in the outer regions of galaxies rotate at unexpectedly high speeds.

这种异常现象表明，存在一种质量巨大且不可见的物质正在施加引力，使恒星的运行速度比预期更快。

This anomaly suggests that a massive, unseen matter is exerting gravitational force, keeping the stars moving faster than expected.

暗物质对于宇宙的结构极其重要。
计算机模拟显示，如果没有暗物质的存在，星系就不会以它们现有的方式形成。

Dark matter is hugely important for the structure of the universe.
Computer simulations show that galaxies wouldn't have formed the way they did if dark matter hadn't been around.

但暗物质是由什么构成的呢？
对此有不同的理论，接下来我们来看其中的几种。

But what does dark matter consist of?
Well, there are different theories, so let's consider a couple of them.

According to the speaker, how do scientists infer the existence of dark matter?

Why does the speaker mention computer simulations?

What will the speaker most likely discuss next?

Professor: Dark matter is a type of matter that doesn’t emit, absorb, or reflect light, making it invisible to current instruments. Despite being unobservable directly, it’s believed to make up about 27 percent of the universe’s mass- energy content. How do scientists know dark matter exists? Well, all the stars in a galaxy rotate around the center of their galaxy. According to basic physics, the farther a star is from the center of a galaxy, the slower it should rotate. However, observations show that stars in the outer regions of galaxies rotate at unexpectedly high speeds. This anomaly suggests that a massive, unseen matter is exerting gravitational force, keeping the stars moving faster than expected.Dark matter is hugely important for the structure of the universe. Computer simulations show that galaxies wouldn’t have formed the way they did if dark matter hadn’t been around. But what does dark matter consist of? Well, there are different theories, so let’s consider a couple of them.

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