Here’s something you can warm up to. Venus. Not only is the second planet from the sun broiling hot, with an average surface temperature of 864°, but it’s dotted with over 1,600 major volcanoes or volcanic features. Radar images of the surface taken through the planet’s perpetual cloud by NASA’s Magellan spacecraft in the early 1990s show evidence of lava channels, enormous lava flows and a volcano, Maat Mons, that rises more than 3 miles (5 km) above the surrounding plains.
Many of Venus’s volcanoes are probably extinct but not all. Last fall a group of scientists working with Magellan images and infrared data collected by the European Space Agency’s Venus Express orbiter and discovered “anomalies” at a volcano named Idunn Mons. Astronomers used the VIRTIS (Visible and InfraRed Thermal Imaging Spectrometer) instrument on the orbiter that maps heat given off by the planet’s surface. Infrared light, which we sense as heat, lies just beyond the red end of the rainbow spectrum.
By combining the Magellan images with high resolution infrared data from the orbiter, scientists identified and mapped distinctive lava flows on the top and eastern flank of Idunn Mons, a volcano in Venus’ southern hemisphere with a base 124-miles (200 km) across, that were hotter than their surroundings. This may indicate that the flows happened recently in geologic time, perhaps right up to the present. Future proposed missions to Venus — NASA’s VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy) and ESA’s En Vision M5 — will combine high-resolution radar and heat mapping to further explore the question of just how volcanically active Venus may still be.
Venus has more volcanoes than any other planet in the solar system. Unlike Earth, where volcanoes are often found in long chains along crustal plate boundaries, Venus has no plates or plate tectonics. The movement of those plates ensures that Earth’s oceanic crust gets recycled regularly, keeping it relatively young — about 100 million years old. Plateless Venus has a much older crust of 300-600 million years, the likely reason it also displays more volcanoes. Without recycling, the old ones stick around!
Most Venusian volcanoes don’t explode like Krakatoa or Mt. Helens but ooze with very runny lavas. This may have to do with its incredibly dense carbon dioxide atmosphere, often described as thick enough to feel like walking through water at a depth of a kilometer. The higher pressure probably “keeps the lid” on explosive eruptions.
Our neighbor planet shines brilliantly in the western sky on January evenings because it’s covered in thick clouds from pole to pole that are good reflectors of sunlight just like clouds are on Earth. Those same clouds also hide the searingly-hot, dry surface and thousands of volcanoes, some of which are probably active to this day. We know this because of sulfur-laden gases, likely spewed by those volcanoes, vary in amount from year to year, decade to decade.
In honor of lava, enjoy this B-52’s classic “Hot Lava.”