This week, the European Space Agency announced the first science results from Planck, a highly anticipated space-born millimeter and sub-millimeter wavelength telescope.
Though Planck's primary mission is to study the Cosmic Microwave Background (CMB), the mission is already allowing astronomers to do science on our Galaxy, star-forming galaxies, and massive galaxy clusters along they way.
The CMB is the "glow" emitted all over the universe just 380,000 years after the Big Bang. By studying the tiny fluctuations in this background with unprecedented resolution, Planck will aide astronomers in filling in some important cosmological details, such as how the early inflation epoch may have occurred, or whether there were primordial gravitational waves.
In order to study the background in that much detail, however, the mission scientists needs to learn as much as they can about all the sources in the foreground in order to properly remove them from the CMB picture. As I sometimes say, one astronomer's noise is another astronomer's data, so science can be done on these foregrounds as they are carefully characterized.