A galaxy is a massive, gravitationally bound system consisting of stars, stellar remnants, interstellar gas, dust, and dark matter. Ranging from dwarf galaxies with millions to giants with hundreds of trillions of stars, these structures orbit a center of mass, often harboring a supermassive black hole at their core.Â
Spiral Galaxies
Spiral galaxies are massive, rotating systems characterized by a flat, disk-like structure with bright, pinwheel-like arms of gas, dust, and young stars spiraling outward from a dense, older central bulge.
Elliptical Galaxies
Elliptical galaxies are massive, smooth, ellipsoidal-shaped collections of stars, commonly described as "red and dead" due to their old, red stellar populations and minimal gas/dust for new star formation.Â
Irregular Galaxies
Irregular galaxies are defined by their lack of a distinct, symmetric shape (no spiral arms or central nucleus) and constitute about 20–25% of all galaxies. They are typically smaller, younger, and rich in gas and dust, driving active star formation.
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