الخميس، 23 يوليو 2020

Venus May Be Geologically Active After All

Venus is sometimes called Earth’s “sister planet,” a distinction that came about before we knew how profoundly unpleasant it was. The crushing atmospheric pressure and clouds of acid make it an unappealing vacation spot, but scientists may have made a discovery that makes it just a little more Earth-like. Research from the University of Maryland suggests Venus may be volcanically active like Earth

In recent years, planetary scientists have started to suspect Venus may be hiding a volcanic secret under all those clouds. Its surface appears to be much younger than Mars or Mercury, both of which have cool interiors. Short of cracking a planet open, the best way to find out if it’s still active inside it to monitor the surface for volcanic activity. In the case of Venus, the planet has structures called coronae dotting its surface. 

These ring-shaped features come from plumes of hot material pushing up to the surface. Coronae come in all shapes and sizes; some have radial cracks, and others have cracks around the perimeter. Some have domes in the middle while others have ridges. They can vary in size from dozens to thousands of miles in diameter, too. The one above is about 96 miles across. Despite the complex collection of features, scientists used to think coronae were all ancient structures on Venus. That wisdom has been questioned with increasing frequency in the last few years, and now we have evidence the coronae may be changing. 

Researchers started by creating a model based on “thermo-mechanic activity” in the planet’s crust. From this, they generated 3D simulations of coronae on Venus so we would be able to identify a “fresh” coronae. The team showed that the myriad coronae shapes are not always a product of the conditions in the planet’s crust. Some are also a product of age.

Next, the researchers looked at the real planet to try and match those simulated features to real coronae. They found coronae at various stages of development that match the model, indicating they are or have been recently active. This isn’t just one or two hot spots, either. There were 37 separate coronae that showed signs of geological activity. 

Scientists are excited by these early results because it could help solve a mystery surrounding Venus. Its surface is overall very young — no more than 500-700 million years. If the planet is geologically active now, it may have been much more so in the past. Eruption events might have resurfaced the planet in the past, giving it a fresh face despite much less going on today.

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