Venus' Atmosphere is So Extreme That It Can Alter the Length of the Planet's Day

Tuesday, 19 June 2018 - 6:08PM
Space
Solar System
Tuesday, 19 June 2018 - 6:08PM
Venus' Atmosphere is So Extreme That It Can Alter the Length of the Planet's Day
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NASA
When discussing space travel, there's a reason we typically focus on Mars and less so on Venus - the second planet in our solar system is utterly inhospitable, with a thick, fast-moving, and toxic atmosphere full of carbon dioxide.

And this atmosphere's not just strong enough to hamper attempts at exploration. It might be strong enough to actually shorten a Venusian day under extreme circumstances, according to a new planetary model developed by researchers from UCLA and University of Paris-Saclay in France in France. 

This new research, just published in Nature Geoscience, claims that an interaction between Venus' atmospheric winds and the mountains on its surface could create an event called a "gravity wave", impacting the planet strongly enough that it can slightly alter its rotational speed. In short, the length of the planet's day can change by two minutes because the gravity wave changed how quickly the planet spun around. 



The researchers pulled data from a Japanese space probe named Akatsuki (which means "dawn") which is currently in orbit around Venus. The probe picked up a strange phenomenon back in 2015 when it found a wave in Venus' cloud tops which was 6,200 miles (10,000 kilometers) long, and thought to be caused by wind rushing against the planet's mountains with such force that the wind is pushed upward before gravity forces it back down.

The phenomenon was thought to be a gravity wave, which can happen on Earth, but those aren't as powerful because our atmosphere doesn't move nearly as fast. The researchers used their model to not only support the prediction that this phenomenon was a Venusian gravity wave, but that it could force the entire planet to fluctuate how it rotates on its axis. The model indicated this could happen by two minutes, but we still need to observe it.

A two minute change seems small, and it seems even smaller when you take into account that Venus already rotates incredibly slowly. A year on Venus lasts 225 Earth days, but a full "day" on Venus takes as long as 243 days, and it also moves in retrograde - which means it orbits in a different direction than the direction it's rotating in, much like the planet Uranus. 

Knowing that its atmosphere can trigger day-changing gravity waves won't help us explore Venus any more easily, but it can help us start to understand the thoroughly bizarre planet next door.
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