This image from NASA's Spitzer Space Telescope shows the spiral galaxy NGC
2841, located about 46 million light-years from Earth in the constellation
Ursa Major. The galaxy is helping astronomers solve one of the oldest
puzzles in astronomy: Why do galaxies look so smooth, with stars sprinkled
evenly throughout? An international team of astronomers has discovered
that rivers of young stars flow from their hot, dense stellar nurseries,
dispersing out to form large, smooth distributions.
This image is a composite of three different wavelengths from Spitzer's
infrared array camera. The shortest wavelengths are displayed in
blue, and mostly show the older stars in NGC 2841, as well as foreground
stars in our own Milky Way galaxy. The cooler areas are
highlighted in red, and show the dusty, gaseous regions of the galaxy.
Blue shows infrared light of 3.6 microns, green represents 4.5-micron
light and red, 8.0-micron light. The contribution from starlight measured
at 3.6 microns has been subtracted from the 8.0-micron data to enhance the
visibility of the dust features.
The shortest wavelengths are displayed in
blue, and mostly show the older stars in NGC 2841, as well as foreground stars in our own Milky Way galaxy.