That faint, fuzzy smudge hanging below the three stars of Orion's belt isn't a star at all — it's a cloud of gas and dust several light years across, and inside it, right now, new stars are being born. This episode explores emission, reflection and dark nebulae, how a cold molecular cloud collapses under its own gravity into clusters of infant stars, why some of those clusters drift apart while others stay locked together for billions of years, and what the famous vivid colours in nebula photographs actually represent.

You'll come away understanding what a nebula really is, the difference between emission, reflection and dark nebulae, how gravity turns a cloud of gas into a protostar, why stars are almost always born in groups, the difference between open clusters and globular clusters and why one type disperses while the other endures, and ...