The space around a newly forming star is a busy construction zone. A giant disk of gas and dust encircles the protostar — the blob of hot material that will someday form the star. Some of the material in the disk feeds into the protostar, while some squirts out into space in high-speed “jets.” The jets can be clumpy, and if one clump overtakes another, it forms a glowing cloud. Two such clouds are in Sagittarius, which is low in the southern sky at nightfall, with its brightest stars forming the outline of a teapot. The clouds are Herbig-Haro 80 and 81. They’re associated with a protostar that’s about 15 times as heavy as the Sun. The disk of gas and dust around it is many times wider than our own solar system. A powerful magnetic field snags charged particles and fires them into space above the protostar’s north and south poles. These jets of material span close to 20 light-years. The jets aren’t smooth, like the spray from a water fountain. Instead, they’re clumpy. The clumps can be
