The Whirlpool Galaxy looks beautiful and swirling in a visible light image (at left.) But the infrared view, at right, shows a maelstrom of chaos, revealing the dense lanes of dust around normally invisible clusters of stars.
Click the image above to enlarge — as always, you can right-click and select "save link as" to grab the high-res version.
According to the Hubble Space Telescope site, the infrared image
is the sharpest view of the dense dust in M51. The narrow lanes of dust revealed by Hubble reflect the galaxy's moniker, the Whirlpool Galaxy, as if they were swirling toward the galaxy's core.
To map the galaxy's dust structure, researchers collected the galaxy's starlight by combining images taken in visible and near-infrared light. The visible-light image captured only some of the light; the rest was obscured by dust. The near-infrared view, however, revealed more starlight because near-infrared light penetrates dust. The researchers then subtracted the total amount of starlight from both images to see the galaxy's dust structure.
The red color in the near-infrared image traces the dust, which is punctuated by hundreds of tiny clumps of stars, each about 65 light-years wide. These stars have never been seen before. The star clusters cannot be seen in visible light because dense dust enshrouds them. The image reveals details as small as 35 light-years across.
Astronomers expected to see large dust clouds, ranging from about 100 light-years to more than 300 light-years wide. Instead, most of the dust is tied up in smooth and diffuse dust lanes. An encounter with another galaxy may have prevented giant clouds from forming.
Massive, higher res versions of the above images at the link. [Hubble Site]