一亿分之一 meaning in English

part per hundred million

Even if experimenters bounce the beams to and fro to increase the effective length of an interferometer ' s arms to more than 100 kilometres , the expected difference in length between the two beams ' paths still amounts to less than a hundred - millionth of the diameter of a hydrogen atom
尽管已经让激光束反复反射来使激光干涉管臂的有效长度增加到超过了100公里，但在光路路程之内，两束光波长差仍小于氢原子直径的一亿分之一。
Designed to predict the motions of hesavenly bodies , it does its job with unbelievable accuracy ? ? better than one in a hndred million for the motion of the earth around the sun ? ? and it remains in daily use to predict the orbits of moons and planets , comets and spacecraft
这个旨在预测天体运行的理论，其准确性令人难以置信? ?以地球绕太阳运转为例，其误差仅略大于一亿分之一，并且时至今日仍然每日要用它来预测卫星和行星、慧星和航天器的运行轨道。