Clouds of sulphur swirl in Venus' hellish polar vortex

To mark 10 years since its Venus Express spacecraft left Earth and journeyed to Venus, The European Space Agency has released this epic set of images showing the hellish, swirling vortex at the hot planet's south pole.

The images -- taken by the craft's Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) between February 2007 and April 2008 -- show thermal-infrared emissions from the tops of clouds in our neighbor planet's atmosphere. Brighter, more vivid parts of the image, like the yellowish "eye" at the vortex's center, are located at lower and hotter altitudes.

Venus' atmosphere is composed almost entirely of carbon dioxide and is the densest of all the planets of the solar system. The planet is also wrapped in a thick layer of cloud made mostly of sulphuric acid. The combination causes extreme greenhouse warming, making the surface extremely hot -- over 840 degrees F.

While wind speeds are generally slow at the planet's surface, they can hit speeds of just under 250 miles per hour at altitudes of about 43 miles above the surface, where the atmosphere spins 60 times faster than the planet itself.

A polar vortex like the one captured by VIRTIS is created when warm air from the equator rises and spirals out toward the planet's poles. Once this air converges and sinks, it creates the swirling vortex.

Venus Express spent eight years studying the planet in detail before the mission ended in December 2014.