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Galaxies

✨ The islands of stars

A galaxy is a huge group of stars, gas, dust, and dark matter held together by gravity. Some galaxies contain millions of stars, while others contain hundreds of billions or even more. The stars inside a galaxy can form systems with planets, and many galaxies also contain clouds of gas where new stars are born.

The Milky Way, the galaxy that contains our Solar System, is a large spiral galaxy with hundreds of billions of stars. Galaxies come in different shapes, including spiral, elliptical, and irregular forms.

They can change over billions of years as they collide, merge, or interact with nearby galaxies. These events can affect the formation of new stars and alter their structures.

By studying galaxies, scientists learn more about the history of the universe, how stars and planets form, and how the cosmos has evolved since the Big Bang. Today, telescopes allow researchers to observe galaxies that are so far away that their light has traveled for billions of years before reaching Earth.

💡 Did you know?

Do you know that galaxies are quite greedy? They can 'swallow' each other! When two galaxies get too close, their gravity pulls them toward each other until they merge to form a single, even larger one. This is what will happen to our Milky Way and its neighbor Andromeda in a very long time.

Can you imagine the number of galaxies? It is thought there are about 2,000 billion of them in the observable universe. It's as if there were more galaxies in space than grains of sand on all the beaches on Earth! Each galaxy itself contains billions of stars.

Why are some galaxies in a spiral? It's because they spin on themselves! The spiral arms are areas where many new stars are born. It's a bit like cream being mixed into hot chocolate: it creates pretty swirls.