A new map created with decades-old radar imagery from NASA’s 1990’s Magellan mission shows the locations of a whopping 85,000 volcanoes on Venus. The detailed map displays where the volcanoes are, how they’re clustered, and how their distributions compare with other geophysical properties of the planet such as crustal thickness.
This comprehensive study of Venus will help planetary scientists answer many outstanding questions about the planet’s geological history, such as why doesn’t it have plate tectonics like Earth? Was it ever habitable, and if so, for how long?
Using archival radar images taken in the 1990s by NASA’s Magellan spacecraft, scientists have found evidence of recent active volcanism on Venus. The images revealed a volcanic vent that changed shape and increased significantly in size over an eight-month period.
The scientists say their findings confirm long-held suspicions that the planet, which is known to have a very geologically young surface and evidence of past volcanic eruptions, is still active today.
“We made the discovery in the most likely place that there should have been new volcanism,” said Robert Herrick, a geophysicist at the University of Alaska Fairbanks, speaking at a briefing on March 15, 2023 from the Lunar and Planetary Science Conference in Texas. “Extrapolating from a data set of one for an entire planet could be dangerous, but most scientists would say it’s pretty good evidence that being able to catch an eruption in an eight-month time frame means that others are taking place as well. It confirms there is modern geological activity on Venus.”
Ever since the announcement last September that astronomers found evidence of phosphine in the clouds of Venus, the planet has been getting a lot of attention. It’s not surprising. Phosphine is a potential biosignature: On Earth, it is produced by microbial life. Might a similar biological process be taking place in the skies of our sister planet? It’s a tantalizing prospect, and is definitely worth examining closely, but it’s too early to be sure. Microbes aren’t the only way to get phosphine. A new paper published on July 12th in the Proceedings of the National Academy of Science suggests that volcanism might instead be to blame for the strange chemistry in the Venusian cloud tops.
Planets move in mysterious ways. Or at least their surfaces do. Earth famously has a system of tectonic plates that drives the movement of its crust. Those plate tectonics are ultimately driven by the flow of material in the mantle – the layer directly below the crust. Now, scientists have found a slightly different deformation mechanic on our nearest sister planet – Venus.
Venus may not have had Earth-like tectonic plates or volcanism for the last billion years, according to a new study. A deep look at a giant impact crater on Venus suggests the planet hasn’t experienced any tectonic activity in the recent past, and might be covered with a in a single outer plate. If so, this would essentially rule out any recent volcanic activity on the planet that many consider Earth’s twin.
Ever since NASA’s Magellan orbiter was able to peak beneath Venus’ dense cloud layer and map out the surface, scientists have puzzled over the planet’s geological history. One of the greatest mysteries is the role volcanic activity has played in shaping Venus’ surface. In particular, there are what is known as “tesserae,” tectonically deformed regions on the surface that often stand above the surrounding landscape.
These features comprise about 7% of the planet’s surface and are consistently the oldest features in their immediate surroundings (dating to about 750 million years ago). In a new study, an international team of geologists and Earth scientists showed how a significant portion of these tesserae appear to be made up of layered rock, which is similar to features on Earth that are the result of volcanic activity.
There’s a problem with Venus. We don’t know how fast it rotates. For a space-faring civilization like ours, that’s a problem.
Measuring the length of day, or rotation rate, of most bodies is pretty straightforward. Mark a prominent surface feature and time how long it takes to rotate 360 degrees. But Venus is blanketed in thick clouds. Those clouds give it its reflectivity, and make it bright and noticeable in the sky, but they make it hard to measure Venus’ day length.
Venus is often referred to as “Earth’s sister planet“, owing to the number of similarities between them. Like Earth, Venus is a terrestrial (aka. rocky) planet and it resides with our Sun’s Circumstellar Habitable Zone (CHZ). And for some time, scientists have theorized that billions of years ago, Venus had oceans on its surface and was habitable – aka. not the hot and hellish place it is today.
However, after examining radar data on the Ovda Fluctus lava flow, a team scientists at the Lunar and Planetary Institute concluded that the highlands on Venus are likely to be composed of basaltic lava rock instead of granite. This effectively punches a hole in the main argument for Venus having oceans in the past, which is that the Ovda Regio highlands plateau formed in the presence of water.
In 1978, NASA’s Pioneer Venus (aka. Pioneer 12) mission reached Venus (“Earth’s Sister”) and found indications that Venus may have once had oceans on its surface. Since then, several missions have been sent to Venus and gathered data on its surface and atmosphere. From this, a picture has emerged of how Venus made the transition from being an “Earth-like” planet to the hot and hellish place it is today.
It all started about 700 million years ago when a massive resurfacing event triggered a runaway Greenhouse Effect that caused Venus’s atmosphere to become incredibly dense and hot. This means that for 2 to 3 billion years after Venus formed, the planet could have maintained a habitable environment. According to a recent study, that would have been long enough for life to have emerged on “Earth’s Sister”.