Viewed as radio emission, the gaseous nebula M17 appears as two sweeping bands. In this false color image, blue represents the lowest intensity of emission and red the highest. The radio emissionΓÇÖs upper band is similar in configuration to the brightest region in a visible light image, but the lower band cannot be seen at all in visible light (both bands are visible in infrared). The dust clouds that obscure much of M17ΓÇÖs visible structure are completely transparent to radio light.
Called bremsstrahlung radiation, this kind of radio emission is generated by electrons in the clouds of very hot gas that surround young stars. The intense radiation from these bright stars (each is hundreds or thousands of times
