They discover an active volcano on Venus

Computer-generated three-dimensional image of the Maat Mons volcano. / NASA

Science | Space

A team of researchers has identified a ~2.2 km2 vent that changed shape in the eight months since two images were taken of the same location.

Elena Martin Lopez

There are many volcanoes on the surface of Venus, but one has never been observed erupting and, until now, there was no evidence of ongoing volcanic activity. Therefore, scientists were not sure if the craters on its surface were calm or simply ancient remains of these geological formations. This Wednesday, a
study published in the journal 'Science' reveals the existence of a vent that has changed shape on the surface of Venus, which they interpret as current active volcanism.

To search for evidence of this activity, scientists have examined radar images of the surface of Venus collected by Magellan's spacecraft between 1990 and 1992. During his two-year mission, Magellan took photographs of Venus' surface from different orbits. and looked at some places two or three times, including areas that were later identified as possible locations of volcanic activity.

“What the Magellan mission revealed is that Venus has a surface that is, in general, geologically as young as Earth, and that it has a similar level of tectonic and volcanic features, although it does not have plate tectonics. Now, in addition, we know that new eruptions occur on its surface every few months, similar to those that characterize some terrestrial basaltic volcanoes," Robert Herrick, a researcher at the Institute of Geophysics at the University of Alaska Fairbanks (USA) told this newspaper. .

The planet Venus.

Although the Magellan data was collected in the 1990s, it has not been until the last decade that current computer hardware and software have allowed it to be analyzed in detail. "The software we use is called JMARS, which is from the same family as Google Earth or Google Maps, but it is oriented towards planetary data," says the researcher. “We restricted the search to areas that were imaged multiple times (in two imaging cycles). Our objective was to identify the volcanic constructions that appeared or were altered between the images, such as volcanic cones, fumaroles or lava flows.

Do you wash the debris?

This is how they identified a ~2.2 km2 vent that had changed shape in the eight months since two images of the same location were taken. This is located on the north side of a shield volcano that is part of a larger volcano, Maat Mons, the largest on Venus. Shield volcanoes are characterized by very gentle slopes, which means that the eruptions tend to be less explosive and more fluid. "On Earth, these types of volcanoes are especially common on oceanic islands, such as Iceland, the Canary Islands, Hawaii, and the Galapagos Islands," Herrick says.

In the images of the second cycle, from the chimney, additional volcanic flows are appreciated downslope. Therefore, the authors interpret the observed changes as indicative of ongoing volcanic activity on Venus. However, it is possible that these flows were already present in the first imaging cycle, but were invisible due to differences in the geometry of the photographs.

A vent at the top of a volcano could expand for two reasons: because an influx of magma disrupts, fills, and expands the vent; or because an underlying magma chamber drains, causing partial collapse bulging. Images of the enlarged vent from the second cycle lead scientists to believe that it is fluid (eg lava) that filled the vent. However, it still cannot be ruled out that what is inside the vent is debris rather than an active or cooled lava lake.

That is, it is possible that the increase in the size of the vent was caused simply by the collapse of the vent walls rather than by magmatism. "We are not aware of any analogous volcanoes on Earth where changes of several kilometers have occurred in a volcanic vent without accompanying volcanic activity, but we cannot yet rule out this possibility on Venus," the scientists say.

The search for volcanoes on other planets, as is being done with research on Mars, is interesting because these natural phenomena create habitable environments for living beings. While this possibility is remote on Venus, based on what is known, the data collected by the Magellan probe could still hold some surprises. The probe photographed 40% of the surface of Venus and, so far, only 1.5% has been analyzed.

The authors of this study are now focused on planning VERITAS and En Vision, two new missions to Venus that the United States and Europe hope to launch in 2031. The radars of these new probes will map the planet just as Magellan did years ago. "We want to understand where, how much, and how often volcanism (and tectonic activity) occurs on Venus," says Herrick.