[Bazmundo]

Contrary to the measurements done by Magellan in the 90's, Venus appears to be rotating slower than previously accepted (or it's slowed down?). ESA's Venus Express probe has found some surface features up to 20km from where they were predicted to be.

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