EARTH’S TWIN? Radar data collected over many years from multiple sources were used to create this beautiful, color-coded portrait of Venus. Venus has roughly the same size, mass, density, and composition as Earth. Until the 1960’s, scientists speculated that Venus may have been very Earth-like, and home to lush, tropical forests. That view changed when new observations confirmed a superheated surface with temperatures over 400˚C (750˚F) and pressures nearly a hundred times that of Earth. But the biggest difference with Earth lies within Venus’ atmosphere. Clouds on Venus are made not of water like they are on Earth, but rather of concentrated sulfuric acid—essentially battery acid. About 700 million years ago, Venus experienced tremendous volcanic activity, flooding the surface with new lava and filling the atmosphere with greenhouse gases, causing a runaway greenhouse effect. Image Credit: NASA/JPL-Caltech
