Spacecraft like Juno, that get up close and personal with the planets they explore, allow us to study features we can’t see from our perspective on Earth. 

Worlds without robot explorers are harder to understand. For most of the modern era of space exploration, Venus has been left alone but that changed in 2015 when the Japanese Venus Climate Orbiter, or Akatsuki, inserted itself into orbit. The results of the past five years of data are starting to pay off in paper after paper, and today in the Geophysical Research Letters, a new paper by Javier Peralta and company announces the discovery of undulating structures in Venus’ clouds that last for decades at a time.

According to Peralta: Since the disruption cannot be observed in the ultraviolet images sensing the top of the clouds at about 70 kilometers height, confirming its wave nature is of critical importance. We would have finally found a wave transporting momentum and energy from the deep atmosphere and dissipating before arriving at the top of the clouds. It would, therefore, be depositing momentum precisely at the level where we observe the fastest winds of the so-called atmospheric super-rotation of Venus, whose mechanisms have been a long-time mystery.

On Earth, the closest we have to this kind of structure is a weather front with a sharp leading edge of clouds. While weather fronts on Earth might span many degrees of latitude, the structure on Venus spans hemispheres, stretching from 30 degrees north to 40 degrees south. Nothing of this proportion has been seen elsewhere in our solar system. 

There is much we still don’t know about Venus, and the more papers like this come out, the more it becomes clear that we don’t even know what questions we need to be asking! Here is to hoping we get more Venus missions in the not-too-distant future.

More Information

Instituto de Astrofísica e Ciências do Espaço (IA) press release 

“A Long‐Lived Sharp Disruption on the Lower Clouds of Venus,” J. Peralta et al., 2020 May 27, Geophysical Research Letters