What's the use of astronomy besides navigation?

In fact, astronomy has been basically combined with some science and engineering to form the so-called "cosmology". I haven't heard of any astronomers in modern times. They are all cosmologists. One of the keys of cosmology lies in its close connection with physics. Because many experiments of physical phenomena can only be carried out under extreme conditions, which cannot be done on earth, scientists look for similar phenomena in the universe to observe. Cosmology is at least much more practical than number theory (the only practical use of the former is to set passwords), which can infer the end of the universe and the composition of unknown matter, which has made great contributions to human life, the most typical of which is antimatter energy. It is uncertain whether the earth itself will still exist in four billion years, and interstellar migration will be put on the agenda in one hundred years.