Sterne, or "stars" in English, are massive celestial bodies composed primarily of hydrogen and helium. They generate energy through nuclear fusion in their cores, which produces light and heat. This process allows them to shine brightly in the night sky, and they can vary in size, temperature, and color, with some being much larger than our own Sun. Stars are often grouped into constellations, which are patterns that have been recognized by various cultures throughout history. These constellations help astronomers locate and identify stars in the sky. The study of stars is a key part of astronomy, which explores the universe and its many phenomena.