Venus Express Maps a Mighty Wind

If men are from Mars and women are from Venus, should we space-loving chicks be annoyed that the red planet gets so much more money and attention than its “feminine” counterpart?

Yeah, Mars is cool and all, what with its tantalizing geologic features and strong potential as a relatively recent host for liquid water.

By contrast, Venus seems so unwelcoming, shrouded in murky clouds of sulfuric acid that whirl at breakneck speed above a dusty surface hot enough to melt lead.

But underneath that hostile exterior lurks the most Earthlike planet we know of right now.

Luckily, while the U.S. is busy cheering on its army of Martian rovers, orbiters, and landers, the European Space Agency (ESA) has been sending out findings from a probe dubbed Venus Express that’s been orbiting our “sister” planet since the spring of 2006.

Today ESA announced results from a study published back in July in the journal Geophysical Research Letters about the first 3-D map of venusian winds covering the entire southern hemisphere.


—ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA/ Universidad del País Vasco (R. Hueso)

Using months of data from the probe’s thermal cameras, a team led by Agustin Sánchez-Lavega of the Universidad del País Vasco in Spain tracked hundreds of Venus’s clouds to create the new map.

Now, astronomers have known for decades that the planet’s clouds lie in a blanket about 28 to 43.5 miles (45 to 70 kilometers) above the barren surface. The top layer of clouds is spinning at a whopping 230 miles (370 kilometers) an hour—about twice as fast as the winds in a Category 3 hurricane here on Earth.

The head scratcher with Venus is that these mighty winds cause clouds to orbit the planet in about four Earth-days, even though Venus itself takes 224 days to spin on its axis. This odd phenomenon is called superotation.


As is often the case with science, the new map of Venus’s winds only deepens the mystery.

Peering into the haze, Venus Express saw that clouds near the equator shifted gears farther down, dropping to 130 miles (210 kilometers) an hour in the lower layers. Closer to the poles, wind speed throughout the cloud layers drops to near zero.

The study also revealed that the superotation is not as constant as once thought, getting stronger at sunset than at sunrise, an effect the astronomers can’t yet explain.

Venus, as seen by the Hubble Space Telescope in ultraviolet


All of which probably adds up to a huge, So what? from the average citizen. What do we get from figuring out the exact complexities of toxic clouds swirling over a superheated world? Even science fiction writers seem to have given up on the idea that Venus could ever be colonized.

The important albeit generic answer is that knowing more about the atmospheres of other planets can help us better model Earth’s systems, especially in predictive simulations of a runaway greenhouse effect. There’s also the serendipity angle, in that you just don’t know what you’re going to find until you take the time to look.

Human Journey