An apparent wobble in the movement of a celestial body caused by the changing geometry between it and the body from which it is observed; also known as geometric libration. The Moon’s librations are optical librations. See Libration.
科学参考收录了60776条科技类词条，基本涵盖了常见科技类参考文献及英语词汇的翻译，是科学学习和研究的有利工具。