It is the gravitational interaction with planets, right?
这是引力与行星的相互作用，对吧？
Its broad arms are distorted by gravitational interaction with a fellow Virgo cluster member, giant elliptical galaxy NGC 4697.
其宽广的旋臂被该星系团另一成员，巨型椭圆星系ngc 4697的引力作用所扭曲。
Astronomers speculate that M51's spiral structure is primarily due to its gravitational interaction with a neighboring smaller galaxy.
天文学家推断，M51的旋涡状结构可能由它与邻近小型星系的相互引力作用而形成。
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