Climates Gone Wrong: Venus and Mars

Abstract

Among the planets of our solar system, the Earth is unique in many ways, including the presence of oceans of liquid water, an oxygen-rich atmosphere, and abundant life. But there are two other planets that resemble our own in many other ways: Mars and Venus. A prime motivation for exploring the solar system has been a desire to improve our understanding of the Earth by comparison with our planetary neighbors. At the beginning of the space age, many scientists anticipated that Venus and Mars would turn out to be basically similar to our own planet. One of the most important lessons of nearly 30 years of planetary exploration has been the realization that this expectation was wrong.