We present the final nine-year maps and basic results from the Wilkinson Microwave Anisotropy Probe ( WMAP ) mission .
The full nine-year analysis of the time-ordered data provides updated characterizations and calibrations of the experiment .
We also provide new nine-year full sky temperature maps that were processed to reduce the asymmetry of the effective beams .
Temperature and polarization sky maps are examined to separate cosmic microwave background ( CMB ) anisotropy from foreground emission , and both types of signals are analyzed in detail .
We provide new point source catalogs as well as new diffuse and point source foreground masks .
An updated template-removal process is used for cosmological analysis ; new foreground fits are performed , and new foreground-reduced CMB maps are presented .
We now implement an optimal C ^ { -1 } weighting to compute the temperature angular power spectrum .

The WMAP mission has resulted in a highly constrained \Lambda CDM cosmological model with precise and accurate parameters in agreement with a host of other cosmological measurements .

When WMAP data are combined with finer scale CMB , baryon acoustic oscillation , and Hubble constant measurements , we find that Big Bang nucleosynthesis is well supported and there is no compelling evidence for a non-standard number of neutrino species ( N _ { eff } = 3.84 \pm 0.40 ) .
The model fit also implies that the age of the universe is t _ { 0 } = 13.772 \pm 0.059 \mbox { Gyr } , and the fit Hubble constant is H _ { 0 } = 69.32 \pm 0.80 km s ^ { -1 } Mpc ^ { -1 } .
Inflation is also supported : the fluctuations are adiabatic , with Gaussian random phases ; the detection of a deviation of the scalar spectral index from unity , reported earlier by the WMAP team , now has high statistical significance ( n _ { s } = 0.9608 \pm 0.0080 ) ; and the universe is close to flat/Euclidean ( \Omega _ { k } = -0.0027 ^ { +0.0039 } _ { -0.0038 } ) .

Overall , the WMAP mission has resulted in a reduction of the cosmological parameter volume by a factor of 68,000 for the standard six-parameter \Lambda CDM model , based on CMB data alone .
For a model including tensors , the allowed seven-parameter volume has been reduced by a factor 117,000 .
Other cosmological observations are in accord with the CMB predictions , and the combined data reduces the cosmological parameter volume even further .
With no significant anomalies and an adequate goodness-of-fit , the inflationary flat \Lambda CDM model and its precise and accurate parameters rooted in WMAP data stands as the standard model of cosmology .