Colonization of Venus
Venus's atmosphere is made mostly out of carbon dioxide, which, after filtering from sulfuric acid, can be used to grow food. Because nitrogen and oxygen are lighter than the carbon-dioxide that makes the atmosphere, breathable-air-filled balloons will float at a height of about . At this height, the temperature is a manageable ; or if we could get higher (see ).
Cloud
Cloud cover has been seen on most other planets in the solar system. Venus's thick clouds are composed of sulfur dioxide (due to volcanic activity) and appear to be almost entirely stratiform. They are arranged in three main layers at altitudes of 45 to 65 km that obscure the planet's surface and can produce virga. No embedded cumuliform types have been identified, but broken stratocumuliform wave formations are sometimes seen in the top layer that reveal more continuous layer clouds underneath. On Mars, noctilucent, cirrus, cirrocumulus and stratocumulus composed of water-ice have been detected mostly near the poles. Water-ice fogs have also been detected on Mars.