This striking infrared light image reveals hidden structures in the M17 nebula. The swaths of color—made from three different wavelengths of infrared light and presented here in false color as red, green, and blue—are generated by regions of the nebula that are difficult or impossible to see in visible light. 
    For a long time M17 posed a mystery to astronomers. Visible light photographs of other gaseous nebulae presented clear evidence that they were sites of new star formation and that light from the new stars heated the nebulae to the point of glowing. Yet visible light photographs of M17 showed no evidence of young star clusters. It took infrared light to solve the mystery; it could penetrate M17’s