The Earth is just too close to the Sun to keep the debris iced.

地球离太阳太近而无法保持岩结冻。

When the Earth was young, it most likely had a ring of rock debris around it.

地球初生时它很可能被一个岩围着。

The volcano is shooting out hot rocks and ash with debris slidding down the side of the mountain.

火山喷发出热岩和灰烬，岩倾泻在了火山周围。

The rise and fall of the sea level over time has helped form a mound composed of gravel and debris.

加上历史时期海平面的升降变化形成了一条砾石和岩组成的。

And the outer moons are dusted with dark stuff, which looks to be debris from Phoebe, a dark-colored lump of a moon.

外圈卫星则嵌满了暗物质，看起来就像Phoebe——卫星上的黑色块状物上的岩。

They found that, assuming the second moon was indeed smaller than the main one, and was made of similar stuff (which, given that it is assumed to have formed from the same ring of debris, seems reasonable).

他们发现，假设第二个月球确实比最大的月球（译者注：指的是 原月）要小，并且由相似的物质组成（考虑到这个月球是从岩的同样光形成的，说它们为相似的物质好像也有道理）。