The Forces Behind Venus’ Super-Rotating Atmosphere
by Theresa Machemer/Smithsonianmag.com
Venus is Earth’s sister planet, similar in size and history, and our closest planetary neighbor in the solar system. It’s also like an evil twin, with a surface hot enough to melt lead covered with thick, sulfuric acid clouds. Venus spins on its axis in the opposite direction as most planets in the solar system, and it takes its time to rotate—one Venusian day lasts 243 Earth days.
That is, if you’re measuring the planet’s rocky surface. Its atmosphere, however, moves about 60 times faster. Powered by constant, hurricane-force winds, Venus’ clouds can lap the planet in just four Earth days. This odd phenomenon is known as super-rotation, and within our solar system it’s only seen on Venus and Saturn’s largest moon, Titan, and the upper reaches of Earth’s atmosphere.
Now, researchers have analyzed imagery taken by Japan’s Akatsuki spacecraft, which has been orbiting Venus since 2015, to figure out where the energy for those winds comes from and how the extreme weather has stuck around for so long. According to the paper, published on April 24 in the journal Science, the super-rotation seems to be driven by heat from the sun.