1. The farther away from the earth's poles, the fewer constellations (starry sky) can be seen in the northern and southern hemispheres. On the contrary, the closer you get to the equator, the more you

1. The farther away from the earth's poles, the fewer constellations (starry sky) can be seen in the northern and southern hemispheres. On the contrary, the closer you get to the equator, the more you can see the northern and southern hemispheres. You can answer if you give points ~

First of all, there is a hypothesis that the star is only blocked by the horizon, that is, the ground is flat and there are no other obstacles, regardless of the influence of atmospheric extinction, so that no matter where we look, half of the celestial sphere is blocked by the ground, which should not be difficult to understand.

Ok, now let's consider the rotation of the earth. Suppose you are at the pole now, no matter what angle the earth turns, the direction directly above your head remains the same, which means that the starry sky you see is the same-of course, it is rotated by an angle, but it is still those stars. It's kind of like looking up and spinning in place.

On the other hand, if you are at the equator, the direction directly above your head changes with the rotation of the earth, which means that the stars you can see are different when the earth turns to different positions, so we can say that we see more at the equator.

But there are two problems.

One is the sun. When we look at the sun (it's daytime), we can't see the stars-not that the stars are not there, but that the sun is too bright for us to see. But because the earth still revolves around the sun, facing the sun in winter and facing the sun in summer, we can see it, just need to change the time.

The second is the influence of the ground. It is assumed that the ground is only covered by the horizon, but this is impossible, because the ground is affected by trees, buildings and mountains. When the altitude angle is low, the artificial light source has a greater impact and the atmospheric absorption is also serious. In fact, there are no stars. Scientifically, it is generally believed that the height angle of the horizon is greater than forty or fifty degrees. From this perspective, even if you stay on the equator for one year, you can't see the 88 constellations all day.