Venus is known to be covered with more volcanoes than any other planet in the solar system.
And now scientists have “strong evidence” that some of these volcanoes are still active.
Images from NASA’s Magellan spacecraft show a vent — a vent through which volcanic activity takes place — on the planet that has changed shape over an eight-month period.
It had grown from about 0.85 square miles (2.2 square kilometers) to 1.5 square miles (3.9 square kilometers), suggesting eruptions and lava flows are underway on Venus, according to researchers at the University of Alaska Fairbanks.
The discovery casts doubt on whether Earth’s sister planet could harbor microbial life.
Two images of a particular vent on the massive shield volcano Maat Mons (pictured) were taken eight months apart and show it has changed shape and size
The opening had grown from about 0.85 square miles (2.2 sq km) to 1.5 square miles (3.9 sq km). Left: vent in February 1991, right: vent in October 1991
Venus is a terrestrial planet similar in size to Earth, but has a surface temperature of about 867°F (464°C) and a pressure 92 times that of our home planet.
VENUS: THE BASICS
Venus, the second planet from the sun, is a rocky planet about the same size and mass as Earth.
However, its atmosphere is radically different from ours – made up of 96 percent carbon dioxide and has a surface temperature of 867°F (464°C) and a pressure 92 times higher than that on Earth.
The inhospitable planet is shrouded in clouds of sulfuric acid that make it impossible to glimpse its surface through the visible light spectrum.
In the past, Venus likely had oceans similar to Earth’s, but these would have evaporated as it underwent a runaway greenhouse effect.
The surface of Venus is a dry desert landscape, which changes periodically due to volcanic activity.
The planet has no moons and revolves around the sun every 224.7 Earth days.
Known as Earth’s “evil twin,” scientists believe Venus was likely habitable 700 million years ago, before it mysteriously became habitable.
Today, Venus is a world of intense heat, crushing atmospheric pressure, and clouds of corrosive acid.
With 65 percent of the planet consisting of a mosaic of volcanic lava plains, scientists have known for some time that Venus has a younger surface than the other “non-terrestrial” rocky planets Mars and Mercury.
While no eruption has yet been recorded on the planet, there is evidence that these volcanoes are still active.
This includes the detection of “hot spots” with above-average temperatures, active “coronae” formed when hot material erupts through the Earth’s crust from within the planet, and sulfur dioxide and phosphine gas in the atmosphere, believed to be released by volcanoes.
But simulations of geodynamic processes on the planet give different predictions about the level of ongoing volcanic activity.
“Estimates of how often eruptions may occur on Venus have been speculative, ranging from a few large eruptions per year to one such eruption every few or even decades,” said author Dr Robert Herrick.
For the new study published today in Scienceresearchers wanted to find more convincing signs of recent eruptions.
The authors analyzed radar images taken by the Magellan spacecraft, which orbited the planet from 1989 to 1994, looking for more conclusive signs of eruptions.
Venus (pictured) is a terrestrial planet similar in size to Earth, but it has a surface temperature of about 867°F (464°C) and a pressure 92 times that of our home planet
Dr. Herrick said: ‘We can now say that Venus is currently volcanically active in the sense that there are at least a few eruptions per year’. Pictured: surface of Venus
Until recently, searching through these images to find evidence of lava flows took a lot of time, which is why not many people have tried to do this.
“It’s really only in the last decade or so that the Magellan data has become available at full resolution, mosaic and easily manipulated by a researcher with a typical personal workstation,” said Dr Herrick.
Between 1990 and 1992, the probe would take pictures at the same location Venus two or three times, and some of these were later identified as potential volcanic hot spots.
Two images of a particular vent on the huge shield volcano Maat Mons were taken eight months apart.
Size Mons is comparable in volume to the largest volcanoes on Earth, but has lower slopes and so is more spread out, said Dr. Herrick.
The researchers saw that between February and October 1991 it had grown and changed from a round formation to an irregular shape.
They also believe that its walls had shrunk and that it was filled almost to the brim with a kind of lava lake in the second image.
However, they couldn’t tell if it was still hot and molten, or if it had had enough time to cool and solidify.
They also saw “volcanic flows downhill from the vent” in the second image, but couldn’t confirm that it was present, just not visible, in the first image.
Therefore, they argue that these changes may very well be due to lava coming through the vent as a result of volcanic activity.
An eruption at the vent, or movement of magma below causing the walls to collapse, would have a similar effect on Earth.
Both cases would occur because of nearby volcanic eruptions and not earthquakes, leading the researchers to rule out one of the latter on Venus.
Dr Herrick said: ‘We can now say that Venus is currently volcanically active in the sense that there are at least a few eruptions per year.
“We can expect the upcoming Venus missions to observe new volcanic flows that have occurred since the Magellan mission ended three decades ago, and we should see some activity as the two upcoming orbital missions collect images.”
EVIDENCE OF VOLCANIC ACTIVITY ON VENUS
In 2015, scientists identified “hot spots” with above-average temperatures picked up during the European Space Agency’s (ESA) Venus Express mission that suggest volcanic activity.
The Venus Express also found anomalies in emissivity — the measure of an object’s ability to emit infrared energy — around the Idunn Mons volcano.
These anomalies strongly indicate geologically recent lava flows in the area.
In 2020, 37 ‘coronae’ were on the surface of Venus that resulted from currently active processes.
These ring-like structures are formed when hot material from deep inside the planet rises through the mantle and erupts through the crust.
Prior to this discovery, the coronae were thought to be signs of ancient activity from 500 million years ago rather than something happening more recently.
Scientists have also reported sulfur dioxide and phosphine gas in the atmosphere of Venus, which are believed to be released by volcanoes.
Now researchers have discovered a “vent” — an opening through which volcanic activity takes place — that changed shape over an eight-month period, adding to this body of evidence.