Tag Archives: spitzer space telescope

Toppling the Pillars

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Today’s press release from the Spitzer Space Telescope shows the Eagle Nebula in a new light. (You can also listen to a podcast about the result.) The Eagle was made famous by the 1995 “Pillars of Creation” Hubble image and perhaps also by the Hubble’s 15th Anniversary image release.

Spitzer is getting into the act now with the gorgeous images above, in addition to an image that came out with the aforementioned press release. The challenge for visualizing the data is that six different filters were used to look at the nebula—3.6-, 4.5-, 5.8-, 8.0-, 24-, and 70-micron filters, to be exact. Since most such pictures are created by assigning three filters to each of the red, green, and blue channels of a digital image, it gets tricky to condense an even greater amount of information into a single snapshot.

The side-by-side presentation of the data helps us piece together the story—namely that the longer-wavelength emission suggests a shockwave of material (most likely from a supervova) coming in from the upper right. It would be interesting to include a tool similar to one on the Hubble education site that would allow a user to turn on or off certain filters and combine them into a single image.

Alternatively, you could take the individual filters’ images from Spitzer and use a tool such as FITS Liberator to constrcut your own color image. (The European Hubble site offers a gallery of images created by users using said tool.)

However it happens, it would be fantastic to experience the images in a more flexible and interactive fashion.

Cosmic Color Schemes

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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.