Figure: The Milky Way in the near infrared (COBE)

Near infrared radiation is less affected by dust extinction than visible light, so by observing in the near infrared, we can get a better idea of the real spatial distribution of the stars. In the central bulge of our Milky Way, the isophotes (contours of equal light intensity) show a boxy shape, typical of a stellar bar viewed almost end-on.

Infrared is a form of radiation that humans cannot see but can feel in the form of heat. Goddard Space Flight Center's Cosmic Background Explorer's (COBE) mission was to test the "Big Bang" theory of the creation of the universe. The theory, first proposed in 1927 by Belgian cosmologist Georges Lematre, holds that the universe began as an incredibly dense "primeval atom" that exploded with tremendous force, unleashing matter and space at the speeds of light.

NASA set out to prove the theory with the help of COBE. In addition to proving the Big Bang, the satellite discovered that the cosmic background radiation had indeed been produced in the Big Bang just as scientists originally speculated. The satellite's data even discovered the primordial temperature and density fluctuations that eventually gave rise to the Milky Way and other large-scale objects found in space today.

In 2006, John C. Mather (NASA Goddard Space Flight Center, USA) and George F. Smoot (University of California, USA) received the Nobel Prize in Physics ''for their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation'', based on measurements made with the help of the COBE satellite.

Image Credit: NASA Goddard Space Flight Center

http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=1624



The approximate shape of the Milky Way Galaxy
and the position of our solar system.
(1 parsec = 3.26 light year)


Credit: Illustration by Tim Jones
image source: http://stardate.org/resources/gallery/gallery_detail.php?id=96

A schematic view of the Milky Way with its main component: the disk, the central bulge, the halo and the globular clusters.























Credit: Addison Wesley
image source:
http://people.brandeis.edu/~wardle/ch16/chapter-16.html