Atmosphere of Uranus vast. The number density of atomic hydrogen in the corona falls slowly with the distance from the planet, remaining as high a few hundred atoms per cm at a few radii from Uranus. The effects of this bloated exosphere include a drag on small particles orbiting Uranus, causing a general depletion of dust in the Uranian rings. The infalling dust in turn contaminates the upper atmosphere of the planet. Uranus has a relatively bland appearance, lacking broad colorful bands and large clouds prevalent on Jupiter and Saturn. No discrete features were observed in Uranus's atmosphere before 1986. The most conspicuous
Atmosphere of Uranus bright tropospheric clouds are rare on Uranus, probably due to sluggish convection in the planet's interior. Nevertheless, observations of such clouds were used to measure the planet's zonal winds, which are remarkably fast with speeds up to 240 m/s. Little is known about the Uranian atmosphere as to date only one spacecraft, "Voyager 2", which passed by the planet in 1986, obtained some valuable compositional data. No other missions to Uranus are currently scheduled. Although there is no well-defined solid surface within Uranus's interior, the outermost part of Uranus's gaseous envelope (the region accessible to remote sensing) is called its