Body: "Astronomy" is the study of the universe and other objects in space that are known and unknown.
Aristarchus of Samos, Hipparchus of Nicaea, Antikythera mechanism are a few specialists of "Astronomy".
People study "Astronomy" in order to to prevent future threats from space, to understand the universe, to explore the outerspace.
What is beyond the sky?, Life outside earth, Matters in Space are a few categories of "Astronomy".