Scientists have shown how the swirling winds and searing heat on Venus work together in a revealing new study.
The surface of Venus is hot enough to melt lead with temperatures averaging 872 degrees Fahrenheit (467 degrees Celsius). This extreme heat is maintained by a thick atmosphere of carbon dioxide that traps the heat on the planet in a greenhouse effect. This atmosphere also sports acid sulfuric clouds and a perpetual, swirling windstorm. In a new study, researchers reveal new insights into this planet's strange wind and heat.
"Winds accelerate as we move upward to increasing altitudes, but we don't know yet why," study lead author Pedro Machado, a researcher at the University of Lisbon in Portugal, said in a statement. "This study throws much light on this."
The team studied the speed of Venus' wind at two different heights, about 12 miles (20 kilometers) apart in the planet's atmosphere. They observed and tracked the clouds at one-hour intervals and, using indirect methods, calculated the speed of the wind pushing the clouds.
They found that the winds were a whopping 93 miles per hour (150 kph) faster at the higher altitude at the top of the clouds than winds at the lower altitude. This finding supports the previously suggested idea that energy from the heat in the lower levels of Venus' atmosphere transfers upwards, accelerating the circulation of the planet's atmosphere. Essentially, the new findings support the idea that surface heat is the source of Venus' strange atmospheric winds.
"We managed to study the vertical component of the wind for the first time, that is, how the energy from the lower and hotter layers is carried up to the top of the clouds, where it leads to the acceleration of the winds," Machado added.
The extreme surface temperatures on Venus produce infrared radiation, or thermal emission, which rises into the air up to the clouds that lie about 30 miles (48 km) above the surface. This thermal emission coming from the surface and traveling upward can be seen in infrared observations of Venus, according to the statement.
The team observed the planet in infrared using the Galileo National Telescope in the Canary Islands in 2012. They made these observations on the same days that the European Space Agency's Venus Express orbiter observed visible light on the top of the planet's clouds. In addition to the findings of the study itself, the team aimed to show how ground-based observations could complement the work of space-based probes.
This study propels the study of Venus and its atmosphere forward, and the team hopes to continue this research as more probes and missions have their sights set on Venus.
Japan's space agency JAXA has a mission that launched to visit Venus called Akatsuki. In 2021, NASA selected two new missions to send to study Venus: Deep Atmosphere Venus Investigation of Noble gasses, Chemistry, and Imaging (DAVINCI+), and Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy (VERITAS).
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Europe is also headed to Venus with the European Space Agency's EnVision mission that aims to study the planet's surface and investigate its history. Machado is a co-investigator for the EnVision mission's infrared spectrograph instrument.
"This work shows the kind of science that will be enabled with the EnVision instruments. We are already demonstrating the great relevance of the science that will be possible with this future mission," Machado said about how this study and its implications for future Venus investigations.
This work was published Feb. 17 in the journal Atmosphere.