About 50 kilometres above Venus’ surface, the crushing heat and pressure below give way to temperatures and air pressure surprisingly close to Earth’s, a region NASA has described as the most Earth-surface-like environment in the solar system — at least by those measures, more forgiving than the surface of Mars.

About 50 kilometres above Venus’ surface, the crushing heat and pressure below give way to temperatures and air pressure surprisingly close to Earth’s, a region NASA has described as the most Earth-surface-like environment in the solar system — at least by those measures, more forgiving than the surface of Mars.

Venus is usually introduced as the planet that makes Mars look gentle. Its surface is hot enough to melt lead, its pressure is comparable to being nearly a kilometre under Earth’s ocean, and its clouds are chemically hostile. Yet about 50 kilometres above that surface, the numbers change in a way that is still easy to miss. NASA’s Venus facts page says that about 30 miles up, or roughly 50 kilometres, temperatures range from 30 to 70 degrees Cel…