By diving into the upper atmosphere of Venus above its north pole, Venus Express has found that the atmosphere there is 60% less dense than predicted. This from a press conference going on right now at the 42nd meeting of the AAS Division for Planetary Sciences. They plan an additional dive campaign during the next month. And they plan more dives, going deeper each time, as they judge the consequences to the spacecraft each time.
To read the abstracts of the Venus Express papers, go here.
Updated: The full press release, with images, can be seen here.