次音速的

The subsonic region is the exterior of the hole: Sound waves can propagate upstream but only at the expense of being stretched, like light being redshifted.

次音速的区域则对应到黑洞之外的时空：声波能够往上游传播，而唯一的代价是波长被拉长，就像光会被红移一样。

CNN -- Fifty-seven years after combat pilot Chuck Yeager broke the sound barrier, NASA will make a second attempt Saturday at flying an aircraft at 5,000 mph -- about seven times Mach 1, the speed of sound.

现在，NASA(美国国家航空和宇宙航行局)将于周六进行时速5000英里的喷气式飞机的第二次试飞，这个速度大约为音速的7倍----7马赫。

CNN -- Fifty-seven years after combat pilot Chuck Yeager broke the sound barrier, NASA will make a second attempt Saturday at flying an aircraft at 5,000 mph -- about seven times Mach 1, the speed of sound.

57年前，战斗机飞行员Chuck Yeager首次突破了音障。现在，NASA(美国国家航空和宇宙航行局)将于周六进行时速5000英里的喷气式飞机的第二次试飞，这个速度大约为音速的7倍----7马赫。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。