Venusian Weather Slows Rotation 90 times the atmospheric pressure of Earth's...
Posted 11 February 2012 - 13:05
Possibly a feature of a different type of core to what was thought, which could lay the blame at another door: the weather. Venus' atmosphere is 90 times denser than Earth's and, while we know our weather patterns can shave microseconds off a given day, the decadal periods of our sister planet's weather cycles could have applied sufficient drag over time to have affected it's day by up to 6.5 minutes (or Magellan got it wrong).
More at ESA: http://www.esa.int/e...XG_index_0.html