Planet and star formation starts with a lot of material collapsing, falling down onto itself because of gravity. In the middle of this, a protostar is being formed. This star will then start to get warm and eventually glow. “Around this forming star, there will be a round, circulating area. This area is called a disk and is full of a lot of material. We’re talking about a lot of gas, for example, CO2 and water. And then there are some small particles which we call dust: very tiny, almost sand grains that are not gas.”