Views of the Horsehead Nebula

This image of the famous Horsehead Nebula in the constellation of Orion (The Hunter) shows how this object appears in different wavelengths of light. From left to right we see the familiar view in visible light, followed by the view at infrared wavelengths, and finally two images at submm wavelengths. In visible light, dust obscures star-forming activity in the Horsehead Nebula. In the infrared, the hot, thin layer of dust and molecules glow, providing a wealth of information on the internal structure, density and kinematics of optically invisible regions. ALMA will show the glowing sub-mm emission (right) at a resolution better than the visible light image (left).