AAS 3: Incredible map of Milky Way

Contributed by
Jan 5, 2009
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Astronomers using the Hubble and Spitzer Space Telescopes have just released an incredible image of the center of the Milky Way:

Hubble and Spitzer map of Milky Way Center. Credit: NASA, ESA, and Q.D. Wang
(University of Massachusetts, Amherst), Jet Propulsion Laboratory, and S. Stolovy
(Spitzer Science Center/Caltech)

Wow. Click to get access to much higher-res versions that will embiggen your brain. They have HUGE versions too.

The image is in the infrared, showing piles of warm gas and dust that litter the galactic center. The weird structures are carved out by massive star winds, supernova explosions, bursts of star formation, and more. Lurking in this image, far too small to be seen, is the supermassive black hole at the heart of our galaxy. Even though our past and future are intertwined -- the black hole formed around the same time the galaxy did, and evidence is that they helped shape each other -- the black hole is invisible. It's smaller than our solar system, and this map is millions of times wider (300 x 115 light years); the black hole is far smaller than a pixel on this scale.

To get an idea of the scale of this image, here's a closeup on the lower left portion:

There's so much to see! The fingers of stalagmite-looking gas on the left are actually columns of gas light years long being eroded by the winds of massive stars, probably that bright cluster to the right of the fingers. On the right is a bright star surrounded by a halo of gas. What's that? I'm not sure; it's probably another just-born massive star carving out a bubble of gas around it. That bubble is several light years across!

And just look at the sheer number of stars in the image! It's hard to grasp just how big a number 200 billion is, but that's how many stars are in the galaxy. There are countless thousands in this one image, and it represents a tiny, tiny fraction of our galaxy.