An unexpected change in the temperature of Neptune

An international team of astronomers that has been observing Neptune from the Earth’s surface for nearly two decades was surprised by the astonishing rise in atmospheric temperature in the past two years, according to a study with the European Southern Observatory (ESO) .), in Chile. This change after sudden cooling also occurs in the south of the ice giant, as the Australian summer progresses. Observations indicate quasi-seasonal changes in the planet’s atmosphere.

The eighth planet of the solar system

Neptune is about 4.5 billion kilometers away and has an average temperature of about -220 degrees Celsius. Its seasons last 40 years, and a full return of the sun, 165 Earth years. In 2005, Neptune began its southern summer, but, farther than expected, instead of a gradual rise in atmospheric temperatures, the ice giant’s atmosphere was cooling, dropping by 8 degrees Celsius between 2003 and 2018, according to IT. The surprise came later, when they observed a temperature increase between 2018 and 2020 of 11 degrees Celsius at the south pole of the distant planet.

“This change was unexpected,” Michael Roman, a researcher at the University of Leicester and lead author of the study, tells ESO. Posted today at Planetary Science Journal. “Since we were observing Neptune during the beginning of the Australian summer, we expected the temperatures to be warmer, not cooler,” the researcher explains.

The evolution of Neptune’s temperature (European Southern Observatory)

“Although Neptune’s warm polar vortex has been known for many years, such rapid polar heating on the planet has not previously been observed,” says the statement from the observatory, which used the VLT’s long-range optical and infrared telescope in the observations. “The team also used data from NASA’s Spitzer Space Telescope and images taken with the Gemini Southern Telescope in Chile, as well as the Subaru Telescope, the Keck Telescope, and the Gemini North Telescope, all of which are in Hawaii,” explains who-that.

summer with nuances

After examining nearly 100 infrared thermal images of Neptune over a 17-year period to reconstruct general trends in the planet’s temperature, they found that the most noticeable changes were in the stratosphere. They did not notice the same thing in the upper troposphere of the planet. “These data provide the strongest evidence to date for sub-global and regional seasonal variation in Neptune’s stratosphere,” the authors commented in the scientific paper. This means that the seasons on this planet are more complex than on Earth.

According to astronomers, this unexpected change in temperature could be caused by changes in stratospheric chemistry, random weather patterns, or the solar cycle. According to ESO, more observations will be needed in the coming years to explore the causes of these fluctuations using more powerful equipment such as ESO’s Future Extreme Range Telescope and James Webb.

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