The planet Neptuno is legendary among astronomers because of its seasonswhat they last 40 years. What scientists did not expect is that their summer would show signs of cooling.
The summer southern region of the planet began 17 years ago, and the data published this Monday confirm that temperatures have cooled.
“That change was unexpected“, has explained Michael Romanastronomer at the British University of Leicester, responsible for the study and quoted in a statement from the European Southern Observatory (ESO).
mysterious planet
Scientists know relatively little about Neptune, the eighth planet in the Solar system. It is the furthest planet from the Sun, which makes its annual orbit last the equivalent of 165 Earth years.
The telescopes of previous generations could not fully fathom the pale light of this stellar object. bluishwrapped in a thick layer of ammonia, ice water and solid methane.
The Voyager 2 probe managed in 1989 to send the first images net of Neptune. And now he is permanently scrutinized by the Hubble Space Telescope and the ESO Large Telescope in Chile.
The atmosphere of Neptune is very dynamic, recalls the study, published by the Planetary Science Journal. The winds They are the most violent known in the solar system: they reach more than 2,000 km/h.
temperature mismatch
The data indicated that normally with the arrival of the southern summer in 2005, the planet would begin to get warmMichael Roman explained.
But the temperature in the southern part of the planet it has dropped an average of eight degrees Celsius between 2003 and 2018. The average temperature of the planet is -200 degrees Celsius, which makes measurements difficult.
Only thanks to the sensitivity of the infrared images Neptune can be seen clearly from large telescopes, explains Leigh Fletcher, a co-author of the study and an astronomer at the University of Leicester. “That technology has only been available for twenty years,” he adds.
Sudden warming in the south
The observations have also detected another phenomenon, the sudden warming of the south pole of Neptune, about 11 degrees Celsius between 2018 and 2020.
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There is not one Explanation of these phenomena, which could be due to an evolution of chemistry in the stratosphere, or to solar cycles.
The impact of solar variations is also discussed among experts to explain the climate change on earth.