After fourteen years of preparation and three years of collecting data, we now have an atlas of the entire infrared sky. This image is just the capstone for a cosmic map that contains 18000 images and 560 million different objects.
This represents the culmination of years of work by NASA's WISE satellite and the astronomers behind it. By studying the universe in infrared wavelengths, we can see objects that are far too dim to be seen in visible light. Each of the 560 million objects represents either a star or entire galaxy, many of which were completely unknown until WISE began its survey three years ago.
Here's how all that data was transformed into the single 2D map of the universe you see up top, according to NASA:
The sky can be thought of as a sphere that surrounds us in three dimensions. To make a map of the sky, astronomers project it into two dimensions. Many different methods can be used to project a spherical surface into a 2-D map. The projection used in this image of the sky, called Aitoff, takes the 3-D sky sphere and slices open one hemisphere, and then flattens the whole thing out into an oval shape.
In the mosaic, the Milky Way Galaxy runs horizontally across this map. The Milky Way is shaped like a disk and our solar system is located in that disk about two-thirds of the way out from the center. So we see the Milky Way as a band running through the sky. As we look toward the center of the galaxy, we are looking through more of the disk than when we are looking at large angles away from the center, and you can see a noticeable increase in stars (colored blue-green) toward the center of the image.
WISE has been responsible for several key discoveries and has already produced over 100 scientific papers. For instance, WISE spotted the first clear evidence of Y-dwarfs, a special type of ultra-cool, ultra-faint failed star that could never be seen in anything other than infrared and even then required WISE's powerful cutting edge sensors to detect. Closer to home, the mission was essential in mapping all of Earth's nearby asteroids, and it helped us spot the first known Trojan asteroid sharing Earth's orbit.