An interesting post at https://spaceweather.com …. archive, January 9th, 2023 … the polar vortex wobbled in December. This caused a giant band of polar stratospheric clouds to migrate from the Arctic Circle. They filled skies at lower latitudes with colourful clouds that could be seen as far south as Italy. Not much sign of them in my part of the UK. Too cloudy and incessant rainfall. Now the skies have cleared and the Sun has shown its face, the stratispheric clouds have gone. Normally, earth’s stratosphere has NO clouds. At all. Only when the temperature up top sinks below minus 85 degrees celsius can water molecules assemble into clouds. At their height in the atmosphere these clouds have colours one might compare with auroras. The people at Space Weather received hundreds of photographic images – and they all came from Europe. None were seen over North America, it seems. A NOAA spokespersonh said the polar vortex can wobble like a top, spinning on its axis if you like. In December it was displaced in the direction of Europ0e. Cold air from the poles was driven to mid latitudes. What causes the vortex to wobble?
At https://phys.org/news/2024-01-mysterious-component-clouds-venus-revealed.html … staying with clouds – but this time on Venus, we learn they contain sulphuric acid droplets, water, chlorine, and iron. What other ingredients are there? Rhomboclase and acid ferric sulphate. Robert also sent in the link to https://phys.org/news/2024-01-images-reveal-neptune-uranus.html … what are the true colours of Neptune and Uranus? The Voyager 2 spacecraft, back in the 1980s, provide us with the classic image of Neptune as a rich blue colour. Uranus, on the other hand, was green. A new study has revealed they are both virtually the same colour – a greenish blue. A pretty dull colour, it woulkd seem.