From knowing the diameter of the Earth's orbit and the apparent angular movement of the star, we can calculate the distance to it.
在知道了地球轨道的直径和恒星变化的角度，我们就能计算出它的距离。
Both nebulae are remarkably symmetric, round, and similar in size, some 2 light-years across or about 2, 000 times the diameter of Neptune's orbit.
两个星云均圆形、对称，而且大小相仿，直径约2光年或约为海王星轨道的2000倍。
When testing different diameter pipeline or vessel, the orbit module is changed only.
检测不同管径的管道时，仅需更换轨道模块。
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