sentence: Astronomy is one of the oldest sciences.
sentences_after: Ancient people used the positions of the stars to navigate, and to find when was the best time to plant crops. Astronomy is very similar to astrophysics. Since the 20th century there have been two main types of astronomy, 'Observational' and 'Theoretical' astronomy. Observational astronomy uses telescopes and cameras to 'observe' or look at stars, galaxies and other astronomical objects. Theoretical astronomy uses maths and computer models to predict what should happen.
concept_name: astronomy
headings: Astronomy