The way the air flows over mountains changes the entire planet’s rotation speed
Damia Bouic, DARTS, ISAS, JAXA
Time is out of joint on Venus. The planet’s thick air, which spins much faster than the solid globe, may push against the flanks of mountains and change Venus’ rotation rate.
Computer simulations show that the thick Venusian atmosphere, whipping around the planet at 100 meters per second, exerts enough push against a mountain on one side and suction on the other side to speed the planet’s rotation rate by about two minutes each Venus day, according to a study in Nature Geoscience June 18.
That’s not much, considering that the planet rotates just once every 243 Earth days. By comparison, Venus’ atmosphere rotates about once every four Earth days. Precise measurements of the planet’s rotation rate have varied by about seven minutes, however. The push and pull of the air over the mountains could help explain the mismatch, with some other force — possibly the