When we talk about planets that had water in the distant past, Mars is usually the planet we are talking about. Scientists have now stated that it is possible that Venus was a temperate planet with liquid water on its surface for 2-3 billion years. Some sort of dramatic transformation began to happen about 700 million years ago causing the planet to become the Venus we know now.
That major transformation changed 80% of the planet. Word of possible water on Venus billions of years ago comes from a new study that was presented recently. The study comes after data from the NASA Pioneer Venus mission from four decades ago found hints that Venus may have had a shallow ocean’s worth of water in its past.
The scientists have investigated whether Venus may have once had a stable climate capable of supporting liquid water, and the study involved five simulations assuming different levels of water coverage. In all five scenarios, the team found that Venus was able to maintain stable temperatures between a maximum of 50 degrees Celsius and a minimum of 20 degrees Celsius for around three billion years.
The team says that a temperate climate on Venus might have existed to this day had there not been a series of events that caused an outgassing of carbon dioxide stored in rocks of the planet about 700 to 750 million years ago. The team believes a near-global resurfacing event may be responsible for the change from an Earth-like climate to the hothouse on Venus today.
Three of the five scenarios estimated ocean depth at an average of 310 meters, a shallow water layer averaging 10 meters, and a small amount of water locked in the soil. One of the scenarios used Earth’s topography and a 310-meter deep ocean, and the last was a world entirely covered by an ocean 58 meters deep. The cause of the outgassing that the researchers believe led to the water loss is a mystery, but is thought to be related to volcanic activity. The team is calling for more Venus missions to gather more data.