On the spot it had occupied was a circular space, exposing an iron ring let into a square flag-stone.
在大石所呆的地方出现了一个圆形的空间，中间有一块四方形的石板，上面有一个铁环。
2
"When we launched, the space age was only 20 years old, so we had no evidence that things last that long," added California Institute of Technology's Ed Stone, Voyager project scientist.
When two such massive objects are whirling around each other, they stir up the space-time fabric, creating ripples like those made by a stone thrown into a pond.