Stars - Page 19

Stars are massive celestial bodies made up of gases, primarily hydrogen and helium, that emit light and heat from nuclear fusion processes occurring in their cores. They are fundamental components of galaxies and are typically found in vast clusters across the universe. Stars vary in size, temperature, brightness, and lifespan, and they are classified into different types based on their characteristics, such as dwarfs, giants, and supergiants.The life cycle of a star begins with the gravitational collapse of a gas cloud, leading to the formation of a protostar, which eventually ignites nuclear fusion, becoming a main-sequence star. Over time, stars evolve into different stages, ultimately leading to phenomena such as supernovae, neutron stars, or black holes upon their deaths. Stars are often observed in the night sky and have been a source of inspiration and navigation for humans throughout history. Their light can take years to reach Earth, allowing us to look back in time as we observe distant stars.