Close look confirms two eyes on Venus

A spacecraft that recently arrived at Venus has confirmed the presence of an unusual storm feature—two giant, hurricanelike eyes within a storm at the planet’s south pole.

The European Space Agency’s Venus Express first observed the vortex soon after the craft entered orbit around Venus on April 11. Express’ initial, distant path provided a global view of the planet, including a glance at the double vortex. In late May, the craft flew over the south pole and took a closer look at the storm.

Two previous missions to Venus more than 2 decades ago, Pioneer-Venus and Mariner 10, caught a glimpse of storms above the south pole, but the double-vortex pattern had never before been discerned.

A spectrometer on Express provided snapshots of the double vortex at various depths by observing the storm at several infrared wavelengths. The instrument reveals that the temperature and cloud density associated with the vortex vary with altitude. It’s as if “we were looking at different structures, rather than a single one,” says Express researcher Pierre Drossart of the Paris Observatory in France.

High-speed winds that blow westward around the planet, combined with the rise and fall of hot air in the atmosphere, are known to create vortices, but how the double vortex formed at the poles remains a puzzle.

The European Space Agency released the latest observations on July 12.