Study of celestial objects, space, and the physical universe.
Stars are enormous balls of hot gas that shine by burning nuclear fuel. Our Sun is just one of billions of stars in the Milky Way galaxy. Galaxies are huge groups of stars, dust, and dark matter, all held together by gravity.
Stars are born in clouds of gas and dust called nebulae. They spend most of their lives fusing hydrogen into helium, shining brightly. Eventually, stars run out of fuel and change—some explode as supernovae, while others quietly fade away.
Galaxies come in different shapes: spiral (like our Milky Way), elliptical, and irregular. Each contains millions or billions of stars, along with planets and nebulae.
By studying stars and galaxies, astronomers learn about how the universe formed, how it changes, and even the origins of the elements that make up everything—including us!
The closest star to Earth (besides the Sun) is Proxima Centauri.
The Andromeda Galaxy is the nearest large galaxy to the Milky Way.
Stars are huge glowing balls of gas, while galaxies are vast collections of stars and other materials.