One night in August 1883, a self-taught astronomer named Edward E. Barnard was scanning the skies and spotted "a large faint nebula, very diffuse" in the constellation of Cassiopeia. It's known as NGC 281 in the official Messier catalog, but its nickname is the Pacman Nebula.
That's because if you look at the image just right (i.e., the top of the picture), it looks a bit like the infamous video game character, with a triangular-shaped "mouth" gobbling up the surrounding gas and dust.
Amateur astronomers have been checking out the pretty faint glow of NGC 281 through visible-light telescopes for ages, but while those telescopes have gotten better and better in terms of resolution since the 1920s, looking in the infrared gives astronomers a fresh set of eyes.
Now the Pacman Nebula is ready for its closeup, thanks to NASA's Wide-Field Infrared Survey Explorer (WISE).
Since its launch in December 2009, WISE has been slowly scanning the cosmos, picking out objects that are invisible to optical telescopes. And it's giving astronomers a new view of the Pacman Nebula.
Specifically, that triangular mouth has some pretty impressive chompers: sharp "teeth" that are, in fact, dense pillars of star-forming regions. Because while Pacman is known for gobbling up objects, nebulae are better known for giving birth to stars.
Here's how it works. As the dust and gas swirls around the nebula, massive knots start to form, until the gas and dust start to collapse under the gravitational attraction. This causes the material at the center to heat up into a "protostar," which starts gathering up even more dust and gas.
Not all that material will make up the star. Some of it might one day become a planet, or an asteroid, or comet - or just a dusty cloud hanging around its parent star.
Check out WISE's close-up of the Pacman Nebula above. See all those red dots scattered around the clouds of dust and gas? Those are baby stars still in the process of forming. That's the kind of detail you get when you look at the skies in infrared.
Image Credit: NASA/JPL-Caltech/UCLA