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'Rings of fire' blaze in outer space

Check out the top space shots of May 2013 — including glimpses of glittering galaxies, a satellite view of a tornado's birth and a portrait of a spacewalker at work.



A galactic ring of fire "burns, burns, burns" with starbirth in this image from NASA's Spitzer Space Telescope. The brilliant ring circling the core of the galaxy, known as Messier 94 or NGC 4736, signals a frenetic round of star formation inside the ring.

Here's what Spitzer's astronomers think is going on: Gravitational pressure in the oval galaxy squeezes gas into hot, young stars. The radiation from those stars warms the surrounding dust, causing it to glow. This image also shows what appears to be a fainter, bluish ring farther out from the center. These arcs represent the outer extent of the galaxy's spiral arms. The denser areas of Messier 94's disk, shot through with greenish filaments of dust, are tucked in between the inner ring and the outer arms.

The colors reflect different wavelengths of infrared light detected by Spitzer. The readings for this image were collected in 2004, before the space telescope ran out of its coolant, but Spitzer's team released this version of the picture just a couple of weeks ago. It's one of the featured images in our Month in Space slideshow for May.

Another image highlights the "ring of fire" solar eclipse that was visible in Australia on May 10. Click through the full slideshow to see that ring and much, much more.

More out-of-this-world slideshows:


Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the NBC News Science Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.