Nighttime on Venus.

With only one planet, Venus is relatively close to Earth and we have been studying it for a long time since the first Venus probe reached the planet in 1978. However, scientists know very little about Venus' night weather. I mean, up to now.

In a new study, the researchers have come up with a new way of using infrared sensors on the Japanese Akatsuki climate orbiter a spacecraft which reached orbit around Venus in 2015 and finally reveal how the weather on the planet looks at night. These detectors found night clouds and bizarre wind flow patterns.

Like the Earth, Venus lies within the "habitable zone" of our sun, has a solid surface and an atmosphere that has time. To understand a planet's climate, scientists are studying the motion of clouds in infrared light. However, while Venus' atmosphere rotates quickly, the planet itself has the slowest rotation of any major planet in our solar system, meaning day and night last quite a long time — about 120 Earth days each.

So far, only time on the "daylight side" of Venus has been readily observable because, even in the infrared, it is difficult to get a clear look at the night side of Venus. There have been infrared sightings of the "nocturnal side" of Venus, but these studies have not been able to clearly show the nocturnal weather of the planet.

To explore this mysterious side of our neighboring planet, the researchers turned to Akatsuki, Japan's first probe to orbit another planet. The probe is designed to monitor Venus and its weather and has an infrared imager that doesn't need sunlight to "see." Despite this design, the image hasn't been able to capture detailed observations of Venus' Nightside. However, by using a new analytical method to process the data captured by the imager, researchers could indirectly "see" Venus' elusive nighttime.

"Small-scale cloud patterns in the direct images are faint and frequently indistinguishable from background noise," co-author Takeshi Imamura, a professor at the Graduate School of Frontier Sciences at the University of Tokyo, said in a statement.

"To see the details, we had to get rid of the noise," he said. "In the realm of astronomy and planetary science, it is common to combine images to do this, because the actual characteristics of a stack of similar images quickly hide the noise. However, Venus is a special case as the entire weather system rotates very quickly, so we had to compensate for this movement, known as super-rotation, to highlight interesting formations for study."

Using this new analytical method, the team observed the north-south winds of the planet at night and found something rather odd.

"What is surprising is that these vehicles are traveling in the opposite direction to their diurnal counterparts," Imamura said. "Such dramatic change cannot be achieved without major consequences. This observation could help us build more precise models of the Venusian weather system that we hope will solve some long-standing and unanswered questions about Venusian weather and probably Earth weather as well."

Using this new method, the researchers think that future studies could reveal new details about the weather on other planets like Mars or even our own planet Earth, according to the statement.

While this work uses existing technology in orbit around Venus, the planet will soon see three new missions arrive that will continue to expand our understanding of Venus and its climate. NASA recently announced two new missions to Venus, DAVINCI+, and VERITAS, and the European Space Agency has announced the launch of the EnVision mission to the planet. The three spacecraft will be launched later this decade and into the early 2030s.