SOFIA, the Stratospheric Observatory for Infrared Astronomy, is a joint project by NASA and the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR).
The left and centre panels of the three-image comparison have the same scale and orientation as the SOFIA image.
The image in the left panel, made at wavelengths visible to the human eye, shows dense clouds of interstellar dust blocking our view into parts of the star forming region, plus the rosy glow of hydrogen gas excited by radiation from the young stars just above the centre of the image.
In the centre panel, the near-infrared image penetrates some of the dust and reveals numerous stars at various stages of formation, embedded inside the clouds.
SOFIA's observations reveal distinctly different aspects of the M42 star formation complex than the other images. For example, the dense dust cloud at the upper left is completely opaque in the visible-light image, partly transparent in the near-infrared image, and is seen shining with its own heat radiation in the SOFIA mid-infrared image. The hot stars of the Trapezium cluster are seen just above the centres of the visible-light and near-infrared images, but they are almost undetectable in the SOFIA image. At the upper right, the dust-embedded cluster of high-luminosity stars that is the most prominent feature in the SOFIA mid-infrared image is less apparent in the near-infrared image and is completely hidden in the visible-light image.