What does Mass want to tell us by writing "At the edge of darkness"?

Mass 写《在黑暗的边缘》想告诉我们什么？

youdao

At the edge of darkness, after about eight hours, I turned around and saw the Earth from our altitude at Hubble, 568 kilometers up.

在黑暗的边缘，大约8个小时后，我转过身来，从哈勃望远镜上看到了568公里高处的地球。

youdao

He looked over the edge of darkness.

他向悬崖下无边的黑暗望去。

youdao

She was at the edge of darkness or the edge of light, depending upon which way you were going.

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TALLADEGA, Ala. (AP) Rain and wrecks pushed NASCAR to the edge of darkness Sunday at Talladega Superspeedway, where three of the biggest names in the sport led the field to final flag.

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He was still cast as the lead in the movie Edge of Darkness, which hit theaters in January of this year.

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