They look like stars to the naked eye.

用肉眼看上去它们像星星。

Most stars are not visible to the naked eye.

大多数星星肉眼看不见。

Maybe you can see the Great Wall clearly from space with binoculars but not with the naked eye.

也许你可以用双筒望远镜从太空中清楚地看到长城，但用肉眼却看不见。

Mercury is a liquid metal, and mercury, the planet, is the fastest moving naked eye heavenly body. Mars, why is Mars red?

水银是一种液态金属，而水星这颗行星，是肉眼能看到的运动最快的天体。火星，为什么火星是红色的？

From end to end, the Milky Way's starry disk, observable with the naked eye and through optical telescopes, spans 120,000 light-years.

从一端到另一端，银河系布满星星的圆盘横跨12万光年，可以用肉眼和光学望远镜观察到。