• Topic 2 Going galactic
Our solar system is huge. Yet it is only a tiny part of a much larger system in space. Our sun is one star in a group of billions of stars found in the Milky Way galaxy. Once, people thought Earth was at the center of the universe. The universe is everything that exists. Now we know that we are not even at the center of our own galaxy!
A galaxy is a group of billions of stars, the objects that orbit the stars, gas, and dust. A galaxy is held together by gravity. There are billions of galaxies in the universe. Galaxies do not stand still. They are always moving. Galaxies can move away from each other or toward each other. Galaxies can be classified based on their shapes. Galaxy can be of different shapes, we have, Spiral galaxies, Elliptical galaxies, and Irregular galaxies.
Our milky way is a spiral galaxy. The closest galaxy to our milky way is Andromeda. It is believed that soon Andromeda and our galaxy will merge into each other. This may make several billion years.