Stars

To kick off learnalittle's WEEK OF SPACE, we look to the stars.

A star is a massive, luminous ball of ionized gas (or plasma) that form in giant, slowly rotating clouds of dust called stellar nurseries. A cloud’s gravity gradually causes it to condense into a sphere; as it collapses, this ball becomes hotter and denser, eventually forming a protostar. Under incredibly high pressure, atoms that normally repel each other begin to collide and combine in a process called nuclear fusion. In the case of a new star, molecules of hydrogen collide to form helium. When the protostar’s heat and pressure hit 1 million °C, fusion begins and the star ignites.