无线电波传播速度同光速一样，假设这种信使接收到我们于本世纪20年代的初次广播，则送往其母行星的信息现在仅走过一半路程。
Radio waves also travel at the speed of light, and assuming such an automatic messenger picked up our first broadcasts of the 1920's, the message to its home planet is barely halfway there.
无线电波传播速度同光速一样，假设这种信使接收到我们于本世纪20年代的初次广播，则送往其母行星的信息现在仅走过一半路程。
Radio waves also travel at the speed of light, and assuming such an automatic messenger picked up our first broadcasts of the 1920's, the message to its home planet is barely halfway there.
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