The Sun is literally a middle-aged star; approaching the midpoint between its birth over 4 billion years ago and its eventual death about 6 billion years from now. But the Sun is one of hundreds of billions of stars in the Milky Way galaxy, and we see them at all different ages, from their spastic births to their (in some cases) hyperspastic deaths. In many cases the way a star dies is foretold by how its born, so the study of star birth is a rich and fascinating field.
It’s also surpassingly beautiful, since stars are formed from the swirling chaos of thick clouds of gas and dust, lit up by the various newborns embedded within. You’ll find no finer example of this than the large nebula called Sharpless 2-239, a sprawling stellar nursery about 500 light years away in the direction of Taurus, and you may find no finer picture of it than this one taken by astronomer Adam Block using the 0.8 meter telescope at the Mt. Lemmon SkyCenter in Arizona:
[Click to ennebulenate, and yes, you want to.]
Isn’t that breathtaking? This image shows a portion of a much larger complex which currently has over a dozen stars forming inside it. Several of the stars you see here are quite young, only a few million years old. Since these are low mass stars like the Sun, and will merrily fuse hydrogen into helium for billions of years, this is like seeing a human baby when it’s less than a month old.
And, like babies will, these stars eject material from both ends: called bipolar outflow, twin beams of material (typically called "jets") are screaming out of these newborns at several hundred kilometers per second in opposite directions. These jets slam into the dense surrounding material, compressing it, heating it up, and causing it to glow. The structure you see fanning out to the lower left is from one of these jets, the one headed more or less toward us. The one moving in the other direction is mostly hidden from our view by the thick dust in the region.
But there’s much much more going on here…