“Tendrils of the coldest stuff in our galaxy”

ESA’s cool infrared Herschel observatory sent its first images back in October last year, just after its launch companion, the even cooler Planck observatory achieved first light. Both are twittering away – Planck and Herschel. But as the BBC notes Planck scientists have now released “a snapshot of the colossal swathes of cold dust that spread through the Milky Way galaxy.”

Wednesday’s pictures come from Planck’s highest frequency channels and cover about 10% of the sky. They show the great filaments of dust within about 500 light-years of Earth. In the wavelengths it is working, Planck is well tuned to see cold matter. Some of the dust it detects is about minus 261C (12K). “We have the ability to look at very cold emission, essentially dust. We can do unbiased searches over the whole sky for these regions that are very important because they are where stars are forming,” Dr Tauber explained.

Nasa chips in here. And provides the wider view. Image credit: ESA and the HFI Consortium, IRAS.

But it’s really ESA’s gig.

“What makes these structures have these particular shapes is not well understood,” says Jan Tauber, ESA Project Scientist for Planck. The denser parts are called molecular clouds while the more diffuse parts are ‘cirrus’. They consist of both dust and gas, although the gas does not show up directly in this image.

There are many forces at work in the Galaxy to help shape the molecular clouds and cirrus into these filamentary patterns. For example, on large scales the Galaxy rotates, creating spiral patterns of stars, dust, and gas. Gravity exerts an important influence, pulling on the dust and gas. Radiation and particle jets from stars push the dust and gas around, and magnetic fields also play a role, although to what extent is presently unclear.

Bright spots in the image are dense clumps of matter where star formation may take place. As the clumps shrink, they become denser and better at shielding their interiors from light and other radiation. This allows them to cool more easily and collapse faster.

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  • joeCanuck

    I wonder how many times in a year these days can your mind be blown away. Used to be so infrequent.
    We’re going to have to find a new expression to replace “empty space”.

  • Mark McGregor


    It never bothers you how they touch these images up?

  • joeCanuck


    Naughty. You make it sound like they’re trying to obfuscate; wrong thread for that.
    They are displaying the data either in E.M. parts of the spectrum that aren’t visible or using enhanced colour techniques so that we/they can make more sense of differences. You’re just not that dense!

  • Kevsterino

    I went to the ESA site and looked at the flyby photos of Phobos.

    Sadly, no evidence of leather goddesses (ala Douglas Adams)

  • Pete Baker


    As Joe points out, there’s no falsification involved.

    The images are visual representations of the data collected.

    Which reveals these structures.

    Further analysis will be done on the basis of the data itself.