Scientists have long struggled to explain why Venus’s atmosphere moves so quickly, with winds racing around the planet far faster than its own rotation.
Now, new research suggests that a daily thermal tide created by solar heating is the main driver of these powerful winds.
The study finds that Venus’s thick atmosphere carries clouds at speeds above 100 metres per second. These winds move about 60 times faster than the planet itself, which rotates once every 243 days. Despite this slow spin, the atmosphere completes a full circuit in just four Earth days.
For years, the source of this extreme “superrotation” was unclear.
The new research identifies a once-per-day thermal tide as the key force that pushes momentum upward through Venus’s dense cloud layers. The team analysed around 20 years of data collected by ESA’s Venus Express and JAXA’s Akatsuki orbiters. These spacecraft monitored atmospheric behaviour using radio signals. The researchers also used numerical models to simulate the planet’s atmospheric circulation.
They report that “diurnal tides play a primary role in transporting momentum toward the tops of Venus’s thick clouds,” revising earlier ideas that twice-daily tides were more influential.
Their work includes the first detailed examination of the Southern Hemisphere, strengthening the conclusion that daily solar heating drives the atmosphere’s rapid motion.
Scientists have debated the cause of Venus’s fast winds for decades.
Data from the 1960s first revealed the atmosphere circling the planet in a matter of days. A review noted that “Although Venus’s atmospheric superrotation was discovered in the 1960s, the cause is still debated.” Many explanations were suggested over the years, including gravity waves and circulation patterns, but none fully answered the question.
The new findings build on this long history of research and bring scientists closer to understanding one of the most baffling features of Earth’s closest planetary neighbour.