Scientists speculate that this cooling is linked to changes in the chemistry of the celestial body’s stratosphere, or that there could be a link with the solar cycle.
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With seasons each lasting forty years, the planet Neptune should be spared from abrupt climate changes. However, it has experienced a marked cooling since the start of its austral summer, seventeen years ago, according to a study published on Monday April 11.
“This change was unexpected”noted Michael Roman, astronomer at the British University of Leicester, responsible for the study and quoted in a press release from the European Southern Observatory (ESO). “We expected the temperatures to rise slowly, not to get colder.”
While its austral summer began in 2005 in its southern hemisphere, Neptune’s average temperature dropped about 8°C between 2003 and 2018, according to the study’s observations. A figure to compare with its average temperature of -200°C. Observations have revealed another phenomenon: the sudden warming of the planet’s South Pole, by some 11°C in 2018 and 2020.
Scientists do not explain the cause of these temperature changes. They assume changes in the chemistry of the stratosphere, random phenomena or even a link with the solar cycle.
Eighth planet of the solar system, for which a year stretches over approximately 165 Earth years, Neptune has an atmosphere composed of a mixture of hydrogen, helium and hydrocarbons.