Volcanology of Venus
The surface of Venus is dominated by volcanic features and has more volcanoes than any other planet in the Solar System. It has a surface that is 90% basalt, and about 65% of the planet consists of a mosaic of volcanic lava plains, indicating that volcanism played a major role in shaping its surface. There are more than 1,000 volcanic structures and possible periodic resurfacing of Venus by floods of lava. The planet may have had a major global resurfacing event about 500 million years ago, from what scientists can tell from the density of impact craters on the surface. Venus has an atmosphere rich in carbon dioxide, with a density that is 90 times greater than Earth's atmosphere.
Europa (moon)
Observations with the Goddard High Resolution Spectrograph of the Hubble Space Telescope, first described in 1995, revealed that Europa has a thin atmosphere composed mostly of molecular oxygen (O). The surface pressure of Europa's atmosphere is 0.1 μPa, or 10 times that of the Earth. In 1997, the "Galileo" spacecraft confirmed the presence of a tenuous ionosphere (an upper-atmospheric layer of charged particles) around Europa created by solar radiation and energetic particles from Jupiter's magnetosphere, providing evidence of an atmosphere.