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Taken by the European Space Agency's Herschel Space Observatory in infrared light (at wavelengths of 70, 250 and 500 microns), this photograph shows stars forming along the dense filaments of gas in an interstellar cloud. The blue region on the left-hand side of the image is known as the Cocoon Nebula.

The filaments are huge, stretching for tens of light years through space, and Herschel has shown that newborn stars are often found in the densest parts of them," NASA explained in an article entitled "Do Cosmic Strings of Gas Come From Sonic Booms." "One filament imaged by Herschel in the Aquila region contains a cluster of about 100 infant stars. Such filaments in interstellar clouds have been glimpsed before by other infrared satellites, but they have never been seen clearly enough to have their widths measured. Now, Herschel has shown that, regardless of the length or density of a filament, the width is always roughly the same."

The team working at Herschel has theorized that exploding stars result in sonic booms, which, after traveling through clouds and giving off most of their energy, finally dissipate into these filaments.

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Image: NASA.

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