Earth’s evil twin Venus was born that way, so our planet may not be destined to become a hellish wasteland, after all

Venus and Earth are the same size, made of similar materials and are next-door neighbours in the solar system. But while Earth is wet and lush with life, Venus is desiccated, acidic and very hot. Planetary scientists have long assumed that whatever happened to Venus to send it down this dark path could one day befall Earth.

Now, Keiko Hamano of the University of Tokyo, Japan, and colleagues have created a new model that suggests Venus was always that way. Heat from the collisions that form planets leaves infant worlds covered in molten magma. Earth and Venus may have formed atmospheres of steam that held some of the heat.

Exoplanet hunt

According to Hamano, planets like Earth that form far enough from the sun can cool within a few million years, their steamy atmospheres condensing into liquid oceans. By contrast, water vapour in the upper atmospheres of planets like Venus born closer to the sun would get stripped away by the solar wind before it could condense to form oceans.


“It’s a clean idea for how, even if the accretionary processes were the same, Venus and Earth would have started out quite different right from birth,” says Lindy Elkins-Tanton of the Carnegie Institution for Science in Washington DC, who was not involved in the new work.

The theory could feed into the hunt for potentially habitable planets around other stars, she adds.

Journal reference: Nature, DOI: 10.1038/nature12163