It’s Crowded Downtown

Contributed by
May 25, 2015
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Funny. I was thinking I want to just post a big, gorgeous, colorful photo showing a bunch of different astronomical objects in one scene, and then I found a note from Derek Demeter, planetarium director at the Seminole State College of Florida. He’s an accomplished astrophotographer, and took this stunning picture of the galactic center last October:

Holy wow! Isn’t that gorgeous? Even better, there’s some very interesting stuff going on here. Let me break it down for you.

This photo was taken of an area of the sky toward the center of our Milky Way galaxy. Like looking downtown from a big city’s suburb, this is the direction where all the action is. The bright pink nebula in the center is M8, the Lagoon Nebula, a star-forming gas cloud roughly 4,000–6,000 light-years away. The pink is due to warm hydrogen, glowing as its energized by the young, hot, massive stars actively being born in the nebula.

To its upper right is M20, the Trifid Nebula, a smaller but still iconic gas cloud that appears to be trifurcated by three dark lanes of dust that meet in its center. It really does look like a cosmic flower. Note the blue cloud to its upper right; that’s dust reflecting the light from young hot stars (which happen to be blue). It’s roughly the same distance from Earth as the Lagoon.

Below center is the sparkly orange brilliance of Mars. When Demeter took this picture, it was about 250,000,000 kilometers from Earth. For comparison, the Lagoon was about 200 million times farther away.

And all this is superposed on the magnificence of the stars of the Milky. You can pick out thousands of them easily enough … but you may also notice that yellowish, washed out glow suffusing the shot. Those are stars too! Millions of them, billions, all so far away their light merges into a background glow. The blackness in the center of the image is where you see fewer distant stars because their light is blocked by thick clouds of dust; complex organic molecules created when stars are born and when they die. In space it’s ethereally thin, but you’re looking through a lot of space here. It adds up.

Amazing, isn’t it, just how much is here to see? If there’s one thing I’ve learned in all my words immersed in astronomy, it’s this: There is no such thing as just a pretty picture.

Speaking of which, check out more of Demeter's work on his 500px page.