Glossary of astronomy facts for kids
This glossary of astronomy is a list of terms and concepts about space and the universe. It helps you understand the amazing things found in out in space.
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An accretion disk is a flat, spinning disk of gas and dust. This material slowly spirals inward towards a very strong gravitational pull, like a star or a black hole. As the material gets pulled in, it heats up and shines brightly, releasing lots of energy. Imagine water swirling down a drain – it's a bit like that, but with cosmic dust and gas!
An active galactic nucleus (often called AGN) is a super bright and powerful area right at the center of some galaxies. This central spot shines with incredible light across all kinds of light waves, from radio waves to X-rays. Scientists believe this huge energy comes from a supermassive black hole that is actively pulling in gas and dust. As the material falls into the black hole, it creates this powerful glow.
An asteroid is like a space rock that travels around the Sun. Think of it as a small, rocky object in our Solar System. Asteroids are much smaller than planets. They can be tiny, like the size of a car, or quite large, up to about 600 miles (1000 km) across. Most asteroids are found in the asteroid belt, which is a region between Mars and Jupiter. Some asteroids even have their own tiny moons orbiting them!
