June 19, 2015 Wired
On the surface, our planet and Venus appear to be virtually identical, sharing a similar size, having an atmosphere and being formed mainly of basaltic and rocky materials, however these similarities are broad and in many aspects Venus is incomparable to our home planet.
It sits closer to the sun, so its year is shorter. It spins on its axis in the opposite direction that Earth spins. Its atmosphere is a choking cloak of carbon dioxide and sulfur dioxide. And its rocky surface, although complex, lacks any evidence of plate tectonics as we know it on Earth.
Now, without plate tectonics, you could think that Venus would be a dead planet. Yet, if you look at some of the surface features on the planet, they look remarkably young — perhaps even erupting in the geologically-recent past (few million years). Unfortunately, that thick atmosphere blocks our view of the surface, so from Earth, we haven’t seen any direct evidence that there are active volcanoes on Venus. There have been times where events in the Venutian atmosphere suggested that an eruption could be occurring. Transient plumes of gases related to volcanic eruptions have been seen, but they could also be explained by upwelling and chemical reactions in Venus’ complex atmosphere.
A new study in Geophysical Research Letters has even more evidence for active volcanoes on Venus, possibly even catching an eruption as it happened! Shalygin and others (2015) examined Venus Express images and found areas that appeared and disappeared on different orbits (so, over the course of weeks to months). These areas were also warmer than the surrounding landscape and they estimate that some of these features were as hot as ~1300-1400ºC. That would put them right in the upper range for basaltic lava (or even komatiite lava). They were relatively small, covering about the same area as lava flow fields on Earth.