  The cosmic microwave background (CMB) temperature maps from the Wilkinson
Microwave Anisotropy Probe (WMAP) are of great importance for cosmology. In
previous work we had developed a pipeline for map-making independently of the
WMAP team. The new maps produced from the WMAP raw data by our pipeline are
notably different to the official ones, and the power spectrum as well as the
best-fit cosmological parameters are significantly different too. What's more,
by revealing the inconsistency between the WMAP raw data and their official
map, we had pointed out that there must exist an unexpected problem in the WMAP
team's pipeline. In this work, we find that the trouble comes from the
inaccuracy of antenna pointing direction caused by a systematical time drift
between the attitude data and the science data in the WMAP raw time-order data
(TOD). The CMB quadrupole in the WMAP release can be exactly generated from a
differential dipole field which is completely determined by the spacecraft
velocity and the antenna directions without using any CMB signal. After
correcting the WMAP team's error, the CMB quadrupole component disappears.
Therefore, the released WMAP CMB quadrupole is almost completely artificial and
the real quadrupole of the CMB anisotropy should be near zero. Our finding is
important for understanding the early universe.
