In a significant breakthrough, an analysis of the mysterious night side of planet Venus has thrown light on several aspects of the planet that had been hidden from science as we know it. The night side of Venus, a planet which rotates only once every 243 Earth days, remains largely hidden from the Sun. And while the brighter side of the planet has been explored and analysed extensively, it is only now that we know what transpires on the planet in the dark.
An analysis conducted by a team led by astrophysicist Javier Peralta from the Japan Aerospace Exploration Agency (JAXA) has found that the powerful winds that make up for the swirling Venusian atmosphere gain strength on the darker side of the planet known for its sweltering heat and corrosive atmosphere.
In search for more details into the mysterious dark side of Venus, Peralta and his team used the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on the ESA's Venus Express spacecraft, which orbited the planet between 2006 and 2014.
What they found was something that had been hidden from scientists exploring the Venusian atmosphere so far. While existing models of the atmosphere had predicted that super-rotation occurred largely the same way on Venus's day and night sides, the new infrared perspective shows the whirling Venusian winds are actually more irregular and chaotic when hidden from the Sun.
The team's research shows that the night side produces large, wavy, and irregular clouds in filament-like patterns that aren't observed on the sunny side, and the team thinks a phenomenon called stationary waves is responsible.
Venus's atmosphere is dominated by strong winds that swirl around the planet at speeds up to 60 times faster than the speed at which the planet turns. This phenomenon, called 'super-rotation', has been observed by scientists by tracking the movement of glinting clouds floating above Venus.
And while the phenomenon of super-rotating winds have been decoded based on the movement of upper clouds in daytime, there were chinks missing in the puzzle, says Peralta.
“Our models of Venus remain unable to reproduce this super-rotation, which clearly indicates that we might be missing some pieces of this puzzle."
"These waves are concentrated over steep, mountainous areas of Venus; this suggests that the planet's topography is affecting what happens way up above in the clouds."
While this is by no means the first time that the Venusian gravity waves -- or stationary waves – have been observed, this is the first time that scientists have managed to take a peek into the dark side of Venus. The data analysed reveals that the influence of these gravity waves is not restricted to elevated regions such as mountains.
However, there was no evidence of them in the lower cloud levels, up to 50 kilometres above the surface, they found.
The reason behind this inconsistency is not known, the team says, as it embarks on another mission to revisit the exiting models of the planet to understand the reason behind it.