Our Solar System, and all other star systems, form from a collapsing nebula. Often called stellar nurseries, nebulae are the birthplace of stars. They are made up of mostly hydrogen but also contain other matter like gases, dust, ice and rock. The gravity of the nebula pulls this matter into the centre, and the nebula experiences a gravitational collapse. If the compression raises the core temperature enough to reach thermonuclear fusion, the centre mass generates a protostar. This process takes about 10 million years.