nebula

As the nebula collapsed because of its gravity, it spun faster and flattened into a disk..随着由于重力引起的星云坍缩，它旋转得越来越快，并变成了盘状。

There is one other possible explanation for what scientists have seen: They could be watching the birth instead of a pulsar wind nebula..对于科学家的最新观察结果，还有其他解释：他们所看到的或许只是一个“脉冲星风星云”的诞生。

As for the spiral itself, current supposition is that this is the result of a star in a binary star system entering the planetary nebula phase, when its outer atmosphere is ejected..至于螺旋本身，最近的推测是这是双子星系统中的一个恒星进入行星星云阶段的结果，此时它的外层大气会被喷出。

horsehead nebula,[天文]马头星云

orion nebula,猎户座星云；猎户星云

planetary nebula,行星状星云

reflection nebula,反射星云

emission nebula,发射星云