New images from Planck, ESA’s cosmological space observatory, show star formation in Orion and Perseus. These lovely images show cold prestellar cores about to burst into life as protostars. Planck is able to show a level of detail not yet seen at these wavelengths and to map the regions in a fantastic new way. These images show radiation with wavelengths of 10 mm (red), 850 microns (green) and 350 microns (blue).
Star formation is hidden from view by dust surrounding the sites where it occurs. Optical light is blocked by dust, but we are able to see the dust itself thanks to submillimetre and far-infrared radiation that still escapes. Until recently we did not have the technology to map such active, hidden regions at these wavelengths. Planck and its sister telescope, Herschel, are changing that using ultra-cold detectors in the vacuum of space, positioned far from the Earth.
These images of star formation in Orion and Perseus show us two very different regions of our galaxy. The Orion molecular cloud complex is huge – if you could see it it would take extend all the way along the well-known constellation – and the above 15×15 degree snap of part of it, shows us prestellar cores and structure in the cold dust that makes up the region. (You can see the full image here). You can see the same part of the sky in other wavelengths using