在地球的赤道上空,发射几颗同步卫星,由它们反射或发射的信号能够辐射全球吗?根据现行高中物理教材,不难得出答案,只要有三颗同步卫星,并且互成120°角即可.但事实却并非如此.我们不妨通过计算来回答这个问题.因为是同步卫星,其运行周期与地球自转一周的时间相同. In the sky above the Earth’s equator, launching several geostationary satellites, can the signals reflected or emitted by them radiate around the globe? According to the current high school physics textbooks, it is not difficult to find the answer, as long as there are three geostationary satellites and they are at an angle of 120° to each other. However, the fact is not the case. We may wish to answer this question by calculation. Because it is a synchronous satellite, its operating cycle is the same as the time it takes for the earth to rotate one week.