In the last installment, I started a discussion about the Orion Nebula. Since it’s such an interesting place, I think I’ll talk about it a little more — it’s got so much to explore!

Astronomers refer to the Orion Nebula as an HII region because it is largely made up of hydrogen gas (H₂), with a dash each of helium, oxygen, nitrogen, and traces of other elements. When the Orion birth clouds are are heated by nearby stars, they glow (emit light) in various colors — transforming it into a glowing emission nebula. The starbirth nursery may look serene in this image, but the nebula is an incredibly active place. Stellar winds scoop out caverns around the newborns, jets of superheated gas streak out from the stars, and lumpy-looking cloud textures are carved out by the combined actions of jets and winds. In the center of the nebula lies a cluster of newborns less than a million years old. None of these stars are likely to have planets — yet, and even if they did, their brightness would make it extremely difficult to find the tiny planetary pinpoints. Yet, there are things forming here that we can spot if we use an infrared-sensitive instrument to do the searching.

Hubble Space Telescope gazed at the central cluster of stars in the Orion Nebula with its optical camera and infrared NICMOS instrument, revealing bright stars in visible light — and hidden among them — about 50 of the so-called “substellar objects” that we all know as brown dwarfs glowing in infrared light. They’re the bright star-like objects in the image on the right. These are too cool to be stars, too hot to be planets and difficult to see, unless you happen to have infrared eyes.

Could our own neck of the galaxy have looked like this about 5 billion years ago? If so, when you gaze at the Orion Nebula, you may very well be see what baby pictures of the Sun and its stellar siblings could have resembled, if there’d been anybody around to do the looking!