Venus is one nasty place. Its atmosphere is made up of nitrogen and carbon dioxide and is so dense that on its surface, it’s the same as being at a depth of about 3000 feet under the surface of the ocean. Temperatures can reach more than 850 degrees Fahrenheit, and clouds of sulfuric acid kilometers thick cover the planet. Yet, as recently as 715 million years ago, the planet could have supported life. That means that complex life could have existed on both Venus and Earth at the same time.
According to a recent NASA study, as long ago as two billion years, Venus was inside the habitable zone of the Sun, had liquid water oceans, and had the topography and atmosphere necessary to support life. Venus is much closer to the Sun than Earth, but that long ago, the Sun was less luminous and smaller, providing 30% less light than it does today. Even with Venus’ proximity, it received only about 40% more light than Earth does today – well within the realm of realism for life.
What Happened to Venus?
As the sun grew in both size and luminosity, Venus’ water evaporated into the atmosphere. Radiation from the Sun broke water molecules into hydrogen and oxygen, and the hydrogen leaked into space, robbing the planet of its water. Carbon dioxide then built up, which heated the planet even more, and produced something called a “runaway greenhouse effect” – Venus literally baked in its own juices.
The study’s findings are extraordinary and provide yet another location within our solar system that may have supported life.
Photo credit: NASA