Neptune just experienced an unexplained temperature shift

[Mark]

One year on Neptune lasts for about 165 Earth years, so a single season can last around 40 years. It's been summer time in Neptune's southern hemisphere since 2005.
Astronomers decided to track the planet's atmospheric temperatures once the southern summer solstice occurred that year.
Nearly 100 thermal images of Neptune taken since then showed that much of Neptune gradually cooled, dropping by eight degrees Celsius between 2003 and 2018.
A study on the phenomenon published Monday in the Planetary Science Journal.
"This change was unexpected," said lead study author Michael Roman, a postdoctoral research associate at the University of Leicester, in a statement.
"Since we have been observing Neptune during its early southern summer, we expected temperatures to be slowly growing warmer, not colder."
Then, a dramatic warming event occurred at Neptune's south pole between 2018 and 2020 and temperatures rose by 11C. This warm polar vortex completely reversed any cooling that occurred before.
This kind of polar warming has never been seen on Neptune until now.
"Our data cover less than half of a Neptune season, so no one was expecting to see large and rapid changes," said study co-author Glenn Orton, senior research scientist at NASA's Jet Propulsion Laboratory, in a statement.
Images were taken using the European Southern Observatory's Very Large Telescope and Gemini South telescope in Chile, along with Hawaii's Subaru Telescope, Keck Telescope and the Gemini North telescope, as well as data from NASA's now-retired Spitzer Space Telescope.

The infrared light emitted by Neptune's stratosphere, or the atmospheric band above the active weather layer, helped astronomers detect the temperature fluctuations.
Frosty Neptune has an average of -220C, and astronomers still don't know what caused these temperature shifts.
For now, they have considered that the unexpected changes could be due to a number of factors.
"Temperature variations may be related to seasonal changes in Neptune's atmospheric chemistry, which can alter how effectively the atmosphere cools," Roman said.
"But random variability in weather patterns or even a response to the 11-year solar activity cycle may also have an effect."
https://www.9news.com.au/technology/neptune-planet-temperature-space-climate-change-telescope-seasons-solar-system/860a2cee-a5ca-488c-a03b-9ab76fedda75

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