At the time, people believed that light waves, just as sound waves, ocean waves or shock waves, had to travel through a medium.

当时，人们认为，光波就像声波、海浪波或冲击波一样，它们的运行必须穿过介质。

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The researchers also charted sound waves passing through nine quiet regions of the sun, where no sunspots were developing, and found no significant anomalies in the waves' travel time.

在无黑子活动的九个太阳宁静区，研究人员发现声波的传播时间没有这么大的变化。

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It takes time for both light and sound to travel.

光和声音的传播都需要时间。

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