Under the force of gravity, the compression resulting from a collapse of the object must release energy. Ages for Earth were derived that were in the tens of millions of years, much less than the geologic estimates of the lime.

在重力作用下，这种来源于物体碰撞的引力收缩一定会释放能量。 地球的年龄也因此被推测出来，大约是几千万年，这个数值比通过石灰岩的地质演变过程推测出来的数值要小很多。

请问老师，红色部分是第二句的主语吗？ that是代词,指代上一句话提到的使用的方法，我的问题是for作为介词后面接一个完整的句子，这种现象常见吗？有类似的句子吗？

第二问题是much less than the geologic estimates of the lime 是ages的同位语吗？

这句话完整的是不是Ages for Earth were derived that were in the tens of millions of years, （which is）much less than the geologic estimates of the lime.

和下面的句子的情况类似 I met John, who is a good friend of mine= I met John, a good friend of mine. 

如果和上述句子类似的话，Ages for Earth were derived that were in the tens of millions of years, （which is）much less than the geologic estimates of the lime. 是不是也属于定语从句中，先行词和从句间隔的现象？

初学语法，还望老师指点，感谢！