gravitational insta-bility

例句：

1. 1.The planet's gravity is a significant factor in its orbit.
   行星的引力是其轨道的一个重要因素。
2. 2. The spacecraft's gravitational insta-bility was tested during the launch.
   航天器在发射过程中测试了其引力稳定性。
3. 3.The scientist discovered that the gravitational insta-bility of the planet had been underestimated.
   科学家发现，该星球的引力稳定性被低估了。