Milky Way False-color IR
The COBE (Cosmic Background Explorer) satellite was developed by NASA's Goddard Space Flight Center to measure the diffuse infrared and microwave radiation from the early universe to the limits set by our astrophysical environment. It was launched November 18, 1989 and carried three instruments, a Far Infrared Absolute Spectrophotometer (FIRAS) to compare the spectrum of the cosmic microwave background radiation with
a precise blackbody, a Differential Microwave Radiometer (DMR) to map the cosmic radiation sensitively, and a Diffuse Infrared Background Experiment (DIRBE) to search for the cosmic infrared background radiation.
This false-color image is of the near-infrared sky as seen by the DIRBE. Data at 1.25,
2.2, and 3.5 µm wavelengths are represented respectively as blue, green and red colors. The image is presented in Galactic coordinates, with the plane of the Milky Way Galaxy horizontal across the middle and the Galactic center at the center. The dominant sources of light at these wavelengths are stars within our Galaxy. The image shows both the thin
disk and central bulge populations of stars in our spiral galaxy. Our Sun, much closer to us than any other star, lies in the disk (which is why the disk appears edge-on to us) at a distance of about 28,000 light years from the center. The image is redder in directions where there is more dust between the stars absorbing starlight from distant stars. This absorption is so strong at visible wavelengths that the central part of the Milky Way
cannot be seen. DIRBE data will facilitate studies of the content, energetics and large
scale structure of the Galaxy, as well as the nature and distribution of dust within the
Solar System. The data also will be studied for evidence of a faint, uniform infrared
background, the residual radiation from the first stars and galaxies formed following the Big Bang.
Credits: The COBE datasets were developed by the NASA Goddard Space Flight Center under the guidance of the COBE Science Working Group and were provided by the NSSDC.