Stock image of a very dark cloud over a city. Istanbul was thrust into darkness on Tuesday as a heavy cloud rolled over the city, nearly blocking out the sun entirely for around 5 minutes.

We are just slowly unravelling these brown-cloud effects. V. Ramanathan. In a study published recently in Nature 2, ... 'Atmospheric brown clouds', which appear as a dark haze on the horizon, ...

Because brown dwarfs are born hot and cool down over time, most of them should see each phase of sand cloud evolution as they age. “We are learning how these brown dwarfs live,” Suárez says.