Orion is the gift that keeps on giving. When you look toward that constellation in the sky, you’re facing a region of massive ongoing star formation. A sprawling cloud of gas and dust occupies Orion’s midsection, most of it thick and opaque. Some of it is illuminated by stars embedded inside, and some by the reflected light of nearby stars.
M78 is a section of the cloud just above Orion’s Belt that’s evidence of the latter. But even then, much of the dust is dark to our eyes. But if you look in the far, far infrared, where warm material glows, a different — and spectacular — view appears:
[Click to blackbodyenate, or grab the 2300 x 3500 pixel version.]
This is actually a combination of two views: one in visible light from the Digitized Sky Survey, and the other from the APEX telescope, which can see light in the submillimeter wavelength range — 1000 times the wavelength the human eye can see. Only cold, cold objects emit at this wavelength, things a few degrees above absolute zero.
The blue material in the image is gas and dust reflecting starlight from nearby blue stars, so it can be seen in visible light. The cold dust, though, threads in front and behind the visible material, and can only be seen by APEX’s eye, tuned as it is to the far infrared. Falsely colored in this image, it glows an eerie orange like fire running through cracks in the nebula.
But it turns out the cracks are the fire itself…