I was really asleep at the wheel for this one. A Spitzer Space Telescope press release from 18 December describes the detection of light from “the Universe's First Objects”—a version of the above image appears as today’s Astronomy Picture of the Day (APOD), which is what tipped me off (sorry to say).
Anyway, the image in question shows light “from a period of time when the universe was less than one billion years old, and most likely originated from the universe's very first groups of objects—either huge stars or voracious black holes.” In the research paper, this light is referred to as “cosmic infrared background (CIB)” radiation, as opposed to the more familiar cosmic microwave background (CMB)” radiation.
Verbiage aside, what I find odd about this image is the choice to color-code intensity as color. A perusal of the aforementioned research article indicates that color information (i.e., the color of the background signal in infrared light) is minimal, but the blobby fluctuations that range from black to purple to pinkish-red to yellowy-white. To my eye, the color range (I hesitate to use the word “spectrum”) seems forced and unnatural—at least as a way of representing intensity—but I dunno. Honestly, however, I admire the choice to show blocked-out regions, which correspond to areas obscured by nearby stars and galaxies—as grey zones. Truth in advertising, as it were.
An associated image related to the press release confuses me even more. For some reason, data from the Cosmic Background Explorer (COBE) is used instead of data from the much more recent Wilkinson Microwave Anisotropy Probe (WMAP). Why? Perhaps becuse WMAP has better resolution…? I can’t say for sure because there are no units presented with the press images, making comparison difficult—i.e., I’d need to go back to the research article and the WMAP and COBE data to compare the two, which is something I haven’t time to do for a blog that is, in fact, not my day job.
So… I have mixed feelings. It’s a complicated concept to introduce to a lay public, but the variety of false color schemes—from COBE to WMAP to the above—muddy the waters. And it’s garish muddying at that.