By Hamish Johnston
Venus is a breezy planet. Planetary scientists have known for some time that its clouds zip along at hundreds of kilometres per hour – speeds on par with Earth’s high-velocity jet stream.
But now a team of researchers looking at data from the European Space Agency (ESA) Venus Express mission have noticed that the winds appear to have accelerated by about 33% over the past six years.
When the mission arrived at Venus in 2006, the average cloud-top wind speed was a bracing 300 km/h. Now, it’s a speedier 400 km/h, according to two independent studies – one led by Igor Khatuntsev at Moscow’s Space Research Institute and the other by Toru Kouyama at the Information Technology Research Institute in Ibaraki, Japan.
The reason for the speed-up is unknown, as is what drives the great speeds at which the planet’s atmosphere rotates.
“The atmospheric super-rotation of Venus is one of the great unexplained mysteries of the solar system,” said ESA Venus Express project scientist Håkan Svedhem. “These results add more mystery to it, as Venus Express continues to surprise us with its ongoing observations of this dynamic, changing planet.”