The Hubble Space Telescope and the Hawaii Keck Observatory and the Californian Lick Observatory thanks to his three decades of observational work, he was able to recognize the connection behind the mysterious disappearance of Neptune’s clouds, NASA reported. The connection is quite surprising, because distant Neptune receives only 0.1 percent of the solar radiation that reaches us, but according to observations, its cloudiness is related to this, and not to its 40-year seasons.
Currently, almost no clouds can be seen on the outer planet, only a few can be observed in the southern arctic region. Those that are otherwise visible in the ice giant’s mid-latitude zones began to disappear in 2019. “I was surprised at how quickly the cloud cover on Neptune disappeared,” said Imke de Pater, a giant planet researcher at the University of Berkeley. Research published in the journal Icarus senior author. “In practice, we saw that the cloud activity almost disappeared in a few months.”
The solar cycle and the clouds of Neptune.
Source: NASA, ESA, LASP, Erandi Chavez (UC Berkeley), Imke de Pater (UC Berkeley)
Even now, four years later, the clouds have not returned. “This is extremely exciting and unexpected, as Neptune’s cloud-poor period prior to this was much less dramatic and did not last as long,” added Erandi Chavez, who led the study.
During the time of maximum solar activity, ultraviolet radiation is more significant, and this triggers photochemical reactions in Neptune’s atmosphere that result in the birth of clouds. When clouds form in the planet’s atmosphere, they also increase the reflected light of the planet through their brightness, so their presence can be measured even if we cannot observe the cloud itself. The solar cycle and the planet’s clouds follow exactly the same path, but Neptune mirrors the Sun’s changes two years later. This is due to the fact that clouds are only slowly formed from the end product of the reactions taking place under the influence of ultraviolet radiation. There are still countless questions about the behavior of the ice giant’s atmosphere that need to be clarified, and further observations will help to answer them.
The current recognition was provided by two special monitoring programs. On the one hand, the OPAL program of the Hubble space telescope, in which the space telescope regularly takes pictures of the atmospheres of the outer planets. On the other hand, the observations carried out in the previously unused twilight period at the Keck Observatory – this period is not suitable for observations in the visual range due to the brighter sky, but it can still be used in other ranges, and thus Keck observes the objects of the Solar System.
2023-08-21 13:02:51
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