- Researchers used infrared images from the Japanese Akatsuki Venus probe
- They then stacked the images and filtered the noise to see wind patterns
- They found that the winds during the night blow opposite the winds during the day.
- This could promote planet-wide super-rotation of the weather system
- It is hoped that new, accurate climate models can be built for Venus in the future.
Winds move backward at night on the sister planet Venus, the ‘evil twin’ of Earth, according to weather forecasts made using space-based infrared imaging.
This is the first time weather patterns have been ‘obviously observed’ at night on Venus, as the night side of the hellish planet is difficult to observe on Earth.
Earth and Venus have a lot in common because they live in the same orbital zone, known as the habitable zone, which is capable of supporting liquid water and possibly life.
Not only are they similar in size and mass, but they both have a solid surface and narrow atmosphere with distinct weather patterns, at one point Venus had liquid water.
With no direct sunlight, it can be very difficult to observe weather patterns at night on a planet, but the Japanese team took infrared observations from an orbiter and then stacked different images to suppress noise and get a clearer picture. did the job.
Using the Venus Climate Orbiter Akatsuki probe, scientists at the University of Tokyo found that night winds blow in the opposite direction to day winds on Venus.
Researchers believe the dayside poleward circulation and the newly discovered nightside equatorial circulation may be promoting the planet’s super-rotation, the brutal east-west circulation of the entire weather system around the equator.
He hopes this observation will allow astronomers to build more accurate models of the Venusian weather, which could also help understand Earth’s weather patterns.
Three main weather patterns on Venus. Researchers believe daytime polar circulation and newly discovered nightside equatorial circulation may promote the super-rotation of the planet that dominates Venus’s surface
With no direct sunlight, it can be very difficult to observe weather patterns at night on a planet, but the Japanese team took infrared observations from an orbiter and then tried to stack different images to suppress noise and get a clear picture. Work done.
Venus: The Basics
Venus, the second planet from the Sun, is a rocky planet about the same size and mass as Earth.
However, its atmosphere is radically different to ours—96 percent carbon dioxide and a surface temperature of 867°F (464°C) and 92 times the pressure on Earth.
The inaccessible planet is enveloped in clouds of sulfuric acid that make the surface impossible to see through the visible light spectrum.
In the past, Venus likely had oceans similar to Earth’s – but these may have evaporated as it went through a runaway greenhouse effect.
The surface of Venus is an arid desert landscape, which is periodically changed by volcanic activity.
The planet has no moon and orbits the Sun every 224.7 Earth days.
Scientists know very little about the weather at night on Venus or any other planet in the Solar System.
This is due to the absence of sunlight, which makes imaging difficult.
Now, researchers have devised a way to use the infrared sensors on the Venus orbiter Akatsuki to reveal the first details of Venus’ night weather.
Their analytical methods can also be used to study Mars and other planets, including the gas giants.
The methods could allow researchers to understand more about the mechanisms underlying Earth’s weather systems by studying and comparing them to other worlds.
To achieve this goal, researchers need to observe cloud motion on Venus day and night at wavelengths of infrared light.
However, until now only the weather on the daylight side was easily accessible.
At first some limited infrared observations of night weather were possible, but these were too limited to paint a clear picture of the overall weather on Venus.
Enter the Japanese Venus Climate Orbiter Akatsuki and its infrared cameras.
Launched in 2010, it is the first Japanese probe to orbit another planet with the goal of observing Venus and its weather system using various instruments on the spacecraft.
Akatsuki carried an infrared imager that does not rely on light from the Sun to see, but even this could not directly resolve the details of Venus’s night.
This gave the researchers the data they needed to see things indirectly, which could then be expanded to get a clearer picture.
“Small-scale cloud patterns in direct images are blurry and often indistinguishable from background noise,” said Professor Takeshi Imamura from the Graduate School of Frontier Sciences at the University of Tokyo.
‘To see the details, we needed to suppress the noise,’ explained Professor Imamura.
‘In astronomy and planetary science, it is common to combine images to do this, because true features within a stack of similar images quickly hide noise.
Data from Venus orbiter Akatsuki showing thermal signature of planet’s nighttime clouds for the first time
New Missions to Venus
NASA and the European Space Agency recently announced three missions to Venus in the coming years.
NASA announced in early June its two new $500 million missions, which will launch over the next 10 years, to understand how Venus ‘became a hell-like world’.
Just a week later, ESA said it would send a probe known as EnVision to study ‘Earth’s evil twin’, targeting a launch in the early 2030s.
‘However, Venus is a special case because the entire weather system rotates very quickly, so we had to compensate for this movement, known as super-rotation, to uncover interesting structures to study.’
Graduate student Keichi Fukuya developed a technique…