The big Hunter in the sky is seen in a new light by Planck, a European Space Agency mission with significant NASA participation. The long-wavelength image shows most of the constellation Orion, highlighting turbid clouds of cold material, where new stars are being stirred into existence.
This long-wavelength image covers a square region of 13 by 13 degrees (which is equivalent to 26 by 26 full moons). It is a three-color combination constructed from three of Planck's nine frequency channels: 30, 353 and 857 gigahertz.
The Planck mission is busy surveying the whole sky at longer wavelengths of light than we can see with our eyes, ranging from infrared to even longer-wavelength microwaves. It is collecting ancient light from the very beginning of time to learn more about the birth and fate of our universe. In the process, the mission is gathering data on our Milky Way galaxy that astronomers are using to see through cold pools of gas and dust, which block visible-light views of star formation.
The image shows one such region in our Milky Way, where stars are actively bursting to life. The much-photographed Orion nebula is the bright spot to the lower center. The bright spot to the right of center is around the Horsehead Nebula, so called because at high magnifications a pillar of dust resembles a horse's head. The whole view covers a square patch of sky equivalent to 26 by 26 moons.
The giant red arc of Barnard's Loop is thought to be the blast wave from a star that blew up inside the region about two million years ago. The bubble it created is now about 300 light-years across.
Note: The below photo, from the Digitized Sky Survey, is of the same region of Orion.
Photo credits: (Planck) ESA/LFI & HFI Consortia; (Digitized Sky Survey) STScI DSS