Idunn Mons, a mountain on Venus was radar mapped by the Magellan space probe. The color overlay is a new thermal map using an infrared detector on the European Venus Express probe, currently orbiting Venus. Red is warmer, and as you can see, Idunn Mons is certainly hotter than expected.
Venus is a lot like the Earth with almost the same diameter (12,100 km versus Earth’s 12,740), it possesses about the same mass (5 versus 6 x 1024 kilos), it orbits the Sun a bit closer in than we do (109 million km versus 147). The total carbon content of the planet is similar to ours, too. It’s also a lot different. While our CO2 is locked up in the oceans and rocks, Venus has all of its CO2 in its atmosphere, which has caused a runaway greenhouse effect. The pressure at the surface is 90 times ours, and the surface temperature is 460° C (almost 900° F). It’s an alien planet.
Until recently it was believed that Venus was also Geologically dead, with little surface changes evident. But according to the team of scientists who took this data, this indicates that Venus was geologically active no more than 2.5 million years ago, and these features may have formed as little as 250,000 years ago and the fact that the hot spots are still around is a strong indicator that activity is still present on Venus.
“Based on a wide range of estimates for rates of volcanism on the surface, we find an upper bound of 250 years to 2.5 million years,” said lead author Suzanne Smrekar from JPL.
Hot spots on Venus
Smrekar also said the temperature variations aren’t huge. “Only a degree or two above the background temperature,” she said. “‘Hot spot’ refers to the geologic environment. On Earth, places like Hawaii where there is hot material coming up from deep inside the Earth to produce volcanism, are referred to as ‘hot spots’.”
One of the reasons Venus is so interesting is that while we study the Earth it often helps to have something else to compare and contrast with. Venus also holds lots of questions for us to try and answer. Why did Venus suffer such a catastrophic runaway greenhouse effect? Why is its surface apparently pretty much all one age (except for this new result)? Why are there hot spots, and are they like ours here on Earth?