This image taken by NASA's Spitzer Space Telescope reveals the stellar nursery W40 (also known as Sh2-64) in infrared light. A young cluster of several hundred stars is located at the center of the nebula, and the stellar winds and radiation coming from these stars have blown bubbles in the surrounding gas. The expanding bubbles have produced the "butterfly" shape as seen in the image. Spitzer's IRAC camera took this mid-infrared image in the bands 8.0 micron, 5.8 micron, 4.5 micron, and 3.6 micron, here represented as red, orange, green, and blue.