2023-10-04 17:15:23
For the first time in almost three decades of detailed observations, the clouds that were so visible on the planet Neptune have practically disappeared.
Photographs of Neptune taken from 1994 to 2022 by the WM Keck Observatory in Hawaii, as well as others taken by NASA’s Hubble Space Telescope, show that clouds, once ubiquitous on the planet, have now almost completely ceased to exist. There is only a cloudy pocket at the south pole of the planet.
The observations also reveal a connection between the disappearance of Neptune’s clouds and the solar cycle, a surprising finding given that Neptune is the planet in our solar system farthest from the Sun and the sunlight it receives is only 1 in 900 parts of the one that the Earth receives.
A research team led by Erandi Chavez, from the University of California at Berkeley, United States, has verified that the clouds normally observed in the mid-latitudes of the planet began to fade in 2019.
“I was surprised how quickly the clouds on Neptune disappeared,” recalls Imke de Pater, professor emeritus of astronomy at the University of California, Berkeley and co-author of the study. Within months, cloud cover decreased dramatically.
Even four years later, cloud cover has not returned to its previous levels. This is a very unexpected phenomenon, especially considering that Neptune’s previous period of low cloudiness was not nearly as marked and prolonged.
An image of Neptune taken with the Keck II telescope on June 21, 2023, shows an almost complete absence of clouds, except near the south pole. (Photo: Imke de Pater, Erandi Chavez, Erin Redwing (UC Berkeley) / WM Keck Observatory)
The discovery adds to observations of the planet’s chaotic and active atmosphere, which, among other things, features clouds of methane whipped by supersonic winds. These winds are the highest ever recorded anywhere in our solar system.
One of the first and most striking images of Neptune’s atmospheric activity was captured by NASA’s Voyager 2 space probe during its flyby of Neptune in 1989. Voyager 2 revealed a massive storm system that was named the “Great Spot.” Dark.”
Since then, other storms and dark spots have been detected, notably a large equatorial storm in 2017 and a large dark spot in northern latitudes in 2018. (Source: Amazings NCYT)
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