peering through the clouds — We finally have proof of active volcanoes on Venus Researchers pored over images from Magellan’s visit to Venus in the early 1990s.

David Rothery, The Conversation – Mar 17, 2023 10:08 am UTC Enlarge / A perspective view across Maat Mons on Venus, based on Magellan radar data.NASA/JPL reader comments 3 with Share this story Share on Facebook Share on Twitter Share on Reddit

Venus is almost the same size, mass and density as Earth. So it should be generating heat in its interior (by the decay of radioactive elements) at much the same rate as the Earth does. On Earth, one of the main ways in which this heat leaks out is via volcanic eruptions. During an average year, at least 50 volcanoes erupt.

But despite decades of looking, weve not seen clear signs of volcanic eruptions on Venus until now. A new study by geophysicist Robert Herrick of the University of Alaska, Fairbanks, which he reported this week at the Lunar & Planetary Science Conference in Houston and published in the journal Science, has at last caught one of the planets volcanoes in the act.

Its not straightforward to study Venuss surface because it has a dense atmosphere including an unbroken cloud layer at a height of 45-65 km that is opaque to most wavelengths of radiation, including visible light. The only way to get a detailed view of the ground from above the clouds is by radar directed downward from an orbiting spacecraft. Advertisement Enlarge / Venus seen in ultraviolet light by Japans Akatsuki spacecraft in December 2016. The surface cannot be seen.ISAS/JAXA

A technique known as aperture synthesis is used to build up an image of the surface. This combines the varying strength of the radar echos bounced back from the ground including the time delay between transmission and receipt, plus slight shifts in frequency corresponding to whether the spacecraft is getting closer to or further from the origin of a particular echo. The resulting image looks rather like a black and white photograph, except that the brighter areas usually correspond to rougher surfaces and the darker areas to smoother surfaces. EnlargeNASA/JPL

Nasas Magellan probe orbited Venus from August 1990 to October 1994 and used this sort of radar technique to map the planets surface with a spatial resolution of about a hundred metres at best. It showed that over 80 percent of the surface is covered by lava flows, but just how recently the youngest of them were erupted, and whether any eruptions continue today, remained a mystery for the next three decades. Page: 1 2 Next → reader comments 3 with Share this story Share on Facebook Share on Twitter Share on Reddit The Conversation The Conversation is an independent source of news and views, sourced from the academic and research community. Our team of editors work with these experts to share their knowledge with the wider public. Our aim is to allow for better understanding of current affairs and complex issues, and hopefully improve the quality of public discourse on them. Advertisement Channel Ars Technica ← Previous story Related Stories Today on Ars