A new image of vast filaments of frigid interstellar dust that reach across our Milky Way galaxy is giving scientists new clues into the forces behind the birth of new stars and the galaxy's shape.
The European Space Agencys (ESA) Planck space observatory took the new cosmic snapshot of dust structures spread across a region of space within 500 light-years of the sun. In the image, the dust filaments link up to the plane of Milky Way galaxy, which appears as a pink, horizontal bar across the bottom of the image.
"What makes these structures have these particular shapes is not well understood," said ESA's Planck project scientist Jan Tauber in a statement.
The new image is color-coded to depict the temperatures of different regions within the view. The whitish-pink areas are regions that are just a few tens of degrees above absolute zero, the theoretical coldest temperature possible in the universe (minus 459 degrees Fahrenheit or minus 273 degrees Celsius). ?Deeper, richer colors mark areas of minus 437 degrees Fahrenheit (minus 261 degrees Celsius). That's just 12 degrees Celsius warmer than absolute zero.
While the warmer dust is concentrated along the plane of the Milky Way, the colder dust hovers above and below the galaxy's plane.
The Planck observatory is designed to study the early universe by studying the cosmic microwave background light emitted just after the Big Bang, which is thought to have created the universe 13.7 billion years ago.
The structures observed by Planck in the new image include molecular clouds in more diffuse regions, as well as so-called "cirrus" dust clouds. They are made of both dust and gas, though the interstellar gas component is not directly visible, ESA officials said.
The clouds are pulled to and fro by a galaxy?s rotation and gravity, and can also be affected by radiation and particle jets that swirl their component gas and dust around.
The bright clumps seen in the Planck image are collections of matter that may offer a safe harbor for new star formation. As these clumps collapse inward on themselves they become denser, offering a more substantial shield against exterior light and radiation.
That shield can allow the clumps to cool and collapse faster to make new stars, ESA officials said.
Planck launched in May 2009 alongside ESA's Herschel infrared space observatory, which is also mapping the universe to make detailed observation of structures on a smaller scale than Planck's view.
The new image from Planck reinforces a cosmic oddity that is perplexing astronomers, ESA officials said. That question is why the large-scale dust filaments seen by Planck are similar to smaller-scale ones observed by Herschel.
"That?s a big question," Tauber said.
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