Put on Your Infrared Glasses

Andromeda Galaxy, Courtesy National Optical Astronomy Observatory
Andromeda Galaxy, Courtesy National Optical Astronomy Observatory

There IS more to the universe than meets the unaided eye. That’s the story I told in one of my planetarium shows, “More Than Meets the Eye” and I’m stickin’ to it. Here’s why: each time you shift wavelength “regimes” and look at the sky, you learn more about what makes objects tick. Take the Andromeda Galaxy for example (since it’s high overhead in northern hemisphere skies these early winter evenings).

This is the typical picture we see of Andromeda. Beautiful, and since it’s the closest spiral galaxy to us, a great example of the general structure of spirals. However, if you look at Andromeda in the infrared, the image changes dramatically.

Spitzer view of Andromeda (infrared)
Spitzer view of Andromeda (infrared)

Suddenly the spiral rings pop into view much more clearly. The dust regions are glowing, and where there’s warmed dust, there’s action going on. In this case, the action comes from hot stars (and other hot events) warming up the surrounding clouds of dust.

Another Spitzer view of Andromeda
Another Spitzer view of Andromeda

You can read more technical detail about this astonishing “infrared makeover” of Andromeda Galaxy at the Spitzer Newsroom, but for now, just compare and contrast the visible-light image with the two infrared images of our nearest spiral neighbor. Lovely, isn’t it?

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