Unexpected Discoveries: How 2 Earth Weather Satellites Stumbled Upon Secrets of Venus

In an unexpected twist, Japan’s Himawari-8 and Himawari-9 weather satellites, built to watch over storms and climate on Earth, have been secretly gathering valuable information about Venus for almost a decade.

These satellites are primarily aimed at our planet, but they can also glimpse other celestial bodies. This includes not just the moon but also planets like Venus, Mars, and even Jupiter.

Gaku Nishiyama, a postdoctoral researcher at the German Aerospace Center (DLR), sparked this discovery. He was originally focused on lunar science when a friend, who has a Ph.D. in astronomy and is a certified weather forecaster, pointed out interesting lunar images in the satellites’ data. This nudged Nishiyama to look at things a bit differently.

His team began to apply the Himawari satellites—launched in 2014 and 2016—as unconventional space telescopes. They looked at how the moon reflected light in infrared wavelengths and were surprised when they found data on other planets, including Venus.

By tracking the exact timing and position of the satellites, they could figure out where Venus would be in the images collected. This method allowed them to analyze how Venus’s brightness changes over time, providing insights into its atmosphere.

The data collected reveals long-term changes in Venus’s cloud-top temperatures and highlights phenomena like thermal tides and Rossby waves.

Nishiyama explains that thermal tides occur when solar heating causes gravity waves in Venus’s cloud layers. Rossby waves, also seen on Earth, are caused by varying forces acting on the planet due to its rotation. Understanding these waves is vital for grasping how heat and momentum move through Venus’s atmosphere.

Recent research indicates that tracking these changes can help scientists better understand the dynamics of Venus’s upper atmosphere. They discovered variations in temperature caused by Rossby waves at different altitudes for the first time, shedding light on the planet’s atmospheric behavior over time.

These findings might reshape how we interpret data from dedicated Venus missions like Japan’s Akatsuki. Nishiyama’s team found differences between data from the Himawari satellites and Akatsuki’s instruments, suggesting that the latter might underestimate Venus’s brightness.

This can significantly impact our understanding of Venus. Nishiyama pointed out that since Earth-observing satellites like Himawari continuously gather data, they can help fill gaps between planetary missions, like Japan’s BepiColombo, which is currently headed to Mercury.

In short, the Himawari satellites are offering a new perspective on Venus and could revolutionize the way we study our neighboring planets. The team thinks that continuing this kind of research will broaden our knowledge in planetary science even further.

For those interested in the details of this exciting work, more information can be found in the journal Earth, Planets and Space, where the team’s findings were recently published.



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