When a gas and dust cloud collapses under its own gravity to form a star, the free-falling gas and dust cause the whole growing star and collapsing cloud to rotate. This rotation causes the in-falling material to form a disk with a thick bulge in the center (like a classic flying saucer). The center of the bulge will become a star while the disk should give birth to will a series of planets.

An interesting side-effect of this rotation is that jets of material end up being shot back out of the collapsing cloud along the rotational axis of the system. When our own Sun was forming, jets probably shot out north and south along the rotational axis of the Sun. The jets result from an interaction between the intense magnetic field of the baby star and the dust and gas falling toward the star. The jets are thus present only as long as the star is actively growing.

This image is a bit complicated. It shows two jets leaving a newly formed star that is obscured and still orbited by a thick disk of cold gas and dust. The upper photo is shot in visible light and shows an obvious jet of hot material streaming some 12 light-years into space! The puffs of stuff moving along the jet indicate that material is ejected in spurts. The lower photo, shot in infrared light, shows the warm glow (red) of a star hidden behind its disk of gas and dust (which are too cold to give off light and so are black). The intense white blob is where the top jet emerges out the top of the dusty disk. The second jet streaming down from the baby star is barely visible as a tiny streak of blue-green; it is largely hidden by the dark disk orbiting the central star.