An international team of scientists was able to study, for the first time, the mysterious night side of Venus, a vastly unknown region of the planet.
Venus is known for being the second planet from the Sun, and also the one to have the longest rotation period in our Solar System. This means that it only rotates once every 243 (Earth) days and that when it does, it goes the other way round.
The mysterious night side of the planet is Venus’s dark half, the one that faces away from the Sun.
Venus’s Mysterious Night Side, Even More Chaotic than Its ‘Day’ One
An extensive number of studies have analyzed Venus’s atmosphere and daylight side. These revealed that this region is dominated by strong winds capable of swirling around the planet even 60 times faster than the rotation of Venus itself.
The phenomenon has been named “super-rotation”. Scientists observed and monitored it by tracking the movements of glinting clouds above the planet. Still, models of this world were unable to reproduce this phenomenon, so scientists believed that they might be “missing a piece of the puzzle”.
Now, this latest study also took a look at the night side of the planet with the VIRTIS. This is the Visible and Infrared Thermal Imaging Spectrometer on the Venus Express spacecraft. The ESA mission orbited Venus in between 2006 and 2014.
VIRTIS led to some surprising and unexpected results, according to the study team. Models had already predicted that super-rotation occurs on both the day and night sides of Venus. However, it couldn’t have predicted that the strong winds of the night side are even more chaotic and irregular than on the other side.
Researchers discovered irregular, wavy and large clouds on this mysterious night side, ones that were also in filament-like patterns and which haven’t been observed on the dayside. The team believes them to be caused by a phenomenon known as stationary waves.
“Stationary waves are probably what we’d call gravity waves – in other words, rising waves generated lower in Venus’s atmosphere that appear not to move with the planet’s rotation,” explains Agustin Sánchez-Lavega, one of the researchers involved.
These stationary waves, detected at higher than expected altitudes, also help raise further questions. Ones that will require further research consider the team.
Current findings were detailed in a paper in the journal Nature Astronomy.
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