After almost ten years of diligent observations of the earliest light in the universe, the Wilkinson Microwave Anisotropy Probe (WMAP) fired its thrusters on September 8, and entered the world's longest and most tedious holding pattern, circling the sun in a so-called graveyard orbit.
WMAP has been a triumph of observational cosmology. It has strengthened the case for cosmic acceleration, one of nature's most mysterious phenomena; measured the composition of the universe, teaching us about dark matter and dark energy; observed the polarization signal, telling us about reionization; provided results consistent with an inflationary origin for the universe, while constraining and even ruling out some of the simplest models; and has left us with some intriguing open questions of its own. To those of us in the field, it seems like only yesterday that we were eagerly awaiting the first 3-year data release from WMAP. Now, the final data, collected ...
