galaxy

A galaxy is a massive, gravitationally bound system composed of billions to trillions of stars, along with gas, dust, dark matter, and other celestial objects. They vary in shape, including spiral, elliptical, and irregular types. Galaxies are the fundamental building blocks of the universe, where stars are born, evolve, and sometimes die, often influencing each other through their gravity. Our home, the Milky Way, is just one of countless galaxies in the universe. They can range from small, compact systems to enormous collections stretching hundreds of thousands of light-years across.