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 ).
Planetary system
The Venus zone is the region around a star where a terrestrial planet would have runaway greenhouse conditions like Venus, but not so near the star that the atmosphere completely evaporates. As with the habitable zone, the location of the Venus zone depends on several factors, including the type of star and properties of the planets such as mass, rotation rate, and atmospheric clouds. Studies of the "Kepler" spacecraft data indicate that 32% of red dwarfs have potentially Venus-like planets based on planet size and distance from star, rising to 45% for K-type and G-type stars. Several candidates have been identified, but spectroscopic follow-up studies of their atmospheres are required to determine whether they are like Venus.