Like racing cars that swerve and hit each other on a circular track, the moons' speed relative to each other is low because they travel in nearly the same orbit.
这有点像是突然转向的赛车在环形赛道上相撞，月亮们也在同一轨道公转，所以他们之间的相对速度很小。
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The general press (enabled by services like Yipit) is able to track with pretty good accuracy what the scale is of the various competitors and their relative growth rates.
With glasses, we'll only need to track where the glasses are and where the eyes are relative to them as opposed to where the eyes are actually looking.