Why can't proxima centauri be seen in the northern hemisphere?

Because proxima centauri's centaur is located in the southern hemisphere of the celestial sphere, there are actually a few southern provinces in China that can be seen. But your question is actually very simple, just like why people in the southern hemisphere will never see the North Star? Because no matter how the earth turns, people in the southern hemisphere are still people in the southern hemisphere. They can't see the North Pole and Polaris. In retrospect, if you don't use tools, you can't see the back of your head no matter how you turn your head.