The very awesome picture above is the first full-sky picture from the Planck Telescope. Launched in 2009 and costing € 700MM, the Planck Telescope is on a mission to measure tiny variations in the oldest light in the universe — cosmic microwave background (CMB) radiation.
In a very literal sense, locating minute differences in the CMB would allow scientists to look back in time about 13.3 billion years, and would go further toward proving the Big Bang Theory.
Very briefly: Cosmic microwave background radiation is an electromagnetic radiation that fills the universe and does not originate from any star, galaxy, or other body. It’s distribution is almost-but-not-quite uniform throughout the universe and the tiny discrepancies in distribution are consistent with what you would expect from a super hot gas being rapidly blown up to the size of the universe. Planck has sensors on board that allow it measure temperatures barely above absolute zero and thereby create a better picture of the irregularities (or, more accurately, the anisotropies) in the CMB radition.