I hasten to remark that these assertions are statements of opinion, not theorems. Astronomy is the most ancient and honorable of the physical sciences. Astronomy is at the forefront of contemporary intellectual activities. All of the subordinate elements of the solar system planets and their satellites, asteroids, comets, meteoroids, dust, and gas are only minor debris left over haphazardly from the formation of a quite mediocre star, the Sun. On several occasions I myself have asserted that one could, as a mental exercise, abolish all objects in the Universe except the Sun, the Moon, and the Earth and that most people would never know the difference in everyday life.
Astronomy is merely one of many applied branches of basic physics.
The only defensible purpose of publicly supported science is its potential for utilitarian applications. Each of these assertions has a measure of validity but each one is contestable. They illustrate the well known tendency to exalt and repeat partial truths. A special appeal of astronomy is that it has to do with where the Earth came from and when, and where it is going and when. Also astronomy has a grandeur of scale, in both space and time, that gives it a special stature.