Life-Friendly Venus? – September 25, 2019
Today, we’re going to talk about a neighboring planet in our solar system: Venus. Venus and Earth are similar in size and mass, but that’s where the resemblance ends. Venus’ surface temperatures are an incredible 864 degrees Fahrenheit (462 degrees Celsius), hot enough to melt lead! Similar to Earth, Venus’ surface holds lava plains, craters, volcanoes and mountains, but, on Venus, they’re hidden under dense clouds of sulfuric acid. The planet’s atmosphere is mostly carbon dioxide and nitrogen, and is about 90 times as thick as Earth’s atmosphere. Life, as we know it, cannot currently survive on the surface of Venus. But what about billions of years ago?
Scientists have recently reported that a water-covered and life-friendly Venus possibly persisted for as long as 3 billion years. But those conditions ended abruptly between 700 – 750 million years ago, when a near-planet-wide release of carbon dioxide stored in surface rocks disrupted the planet’s atmosphere and triggered its transformation to the hothouse of today (Earthlings, take notice!).
Venus is currently bombarded with about twice as much solar radiation as Earth, and some experts have suggested that it lies too close to the sun to have ever hosted oceans at all. Nevertheless, new computer models show that billions of years ago, that radiation wouldn’t have prevented Venus from having water on its surface.
Using computer simulations, scientists created five scenarios that used different topographies for the planet’s surface; varying amounts of ocean coverage; different chemical compositions in the atmosphere; and different epochs in time. In all of their simulations, Venus maintained stable surface temperatures for about 3 billion years of between 68 F (20 C) and 122 F (50 C). Under those conditions, liquid water — and possibly life — could have been feasible!