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 Venus is an extremely rare event, and the last solar transit of the planet before 2004 was in 1882. The most recent solar transit was in 2012; the next one will not occur until 2117. The Venus Express spacecraft formerly in orbit around the planet probed deeper into the atmosphere using infrared imaging spectroscopy in the 1–5 µm spectral range. The JAXA probe Akatsuki (Venus Climate Orbiter), launched in May 2010, is studying the planet for a period of two years, including the structure and activity of the atmosphere, but it failed to enter Venus orbit in December 2010. A second