1) Constellations are groups of stars that appear to form patterns in the night sky, though the stars within a constellation are often very far apart in reality.
2) Many early cultures saw patterns among the stars and associated them with myths and stories from their traditions, with most modern constellations derived from Greek mythology.
3) While constellations shift positions in the sky throughout the night and seasons due to Earth's rotation, they have been used for navigation, to map the sky, and bring order to observations of space.