Which term refers to a huge system of gases, dust, and stars, generally containing billions of Solar Systems?

The term that refers to a huge system of gases, dust, and stars, generally containing billions of solar systems, is a galaxy. Galaxies are vast collections of stars, stellar remnants, interstellar gas, dust, and dark matter, typically ranging from millions to trillions of stars within each one. They can vary in size and structure, forming distinct shapes like spiral, elliptical, or irregular.

In contrast, a comet is a small celestial body that orbits the Sun, primarily made of ice and dust. A planet is a large celestial body that orbits a star, is spherical in shape, and has cleared its orbital path. A constellation is a group of stars that form a recognizable pattern in the night sky, often named after mythological figures or objects, and does not refer to a large system like a galaxy.