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Explainer: Venus Volcanoes May Be Alive After All

Venus is looking hot. And it looks like lava might be causing it.

Venus is looking hot.

This past week, a team of researchers using the now-dead Venus Express spacecraft revealed hotspots on the surface shooting up by several hundred degrees. Their best guess as to what's happening? Lava from active volcanoes.

NEWS: Earth-Based Radar Unveils Venus' Mysterious Surface

We all know that Venus is a hellish world that killed some Soviet landers in minutes. Its average surface temperature would easily melt lead. But even on the surface trapped in a runaway greenhouse effect, the hotspots stood out. So what do we know about volcanoes on Venus?

Recent lava flows were first reported in 2010, when data from Venus Express was compared to the older NASA Magellan spacecraft, which mapped elevations. Scientists saw compositional differences in the lava-soaked terrain compared to what was around it - specifically, minerals that are abundant in lava on Earth.

"Recent", however, was a relative term that could mean hundreds of years ago, or millions. Here's an example of what Venus Express saw on the volcanic peak Idunn Mons. More concrete evidence came in 2012, when scientists reported spikes in sulfur dioxide noted by Venus Express after six years of work. The gas is generated by volcanoes, so this provided even more evidence that the volcanoes are awake.

NEWS: Active Volcanoes Revealed on Venus

Why are volcanoes so important? One reason is they reveal what is happening on the insides of the planet. And what we know shows that Venus was or is extremely active. The planet has more than 1,600 large volcanoes or volcanic features and many smaller ones, according to Oregon State.

But here's the rub (literally) - plate tectonics don't appear to be involved in a big way. On Earth, colliding tectonic plates create volcanic activity. But the chains of volcanoes and rifts on our planet aren't in evidence on Venus.

The Venus volcanoes, added Oregon State, also appear to be mostly of a single type: fluid lava flows. You won't see, for example, ashy volcanoes like on Earth. Reasons could include the high pressure at the surface (which requires the volcanoes be of higher pressure to erupt) and that there is no water on Venus. Water is a constant in Earth's volcanic explosions, which is no surprise as it is abundant on our planet.

ANALYSIS: The Metallic Snow-Capped Mountains of Venus

To learn more about Venus volcanoes will likely require another long-term mission, but unfortunately there is nothing firmed up yet. A proposed U.S. concept called the Venus In Situ Explorer would look in more detail at the atmospheric composition to get clues for Venus' interior. There also could be unexamined data in the Venus Express archive that will reveal more when researchers get a chance to look at it.

Artist’s conception of a volcanic eruption on Venus.