According to the new research paper, Venus has obvious volcanic activity. Scientists have observed that lava flows are changing the landscape of Venus. It is still going on, but this time, strictly speaking, is 1991, more than 30 years ago.
Venus and Earth are very similar in size and mass, but the biggest difference is that Venus does not have plate tectonics. Earth’s plate boundaries are usually prime sites for volcanic activity, but Venus seems to lack this mechanism. A recent study by Robert Herrick of the University of Alaska’s Fairbanks Institute of Geophysics shows a nearly 1-square-mile crater on the surface of Venus observed by the Magellan spacecraft for eight months in 1991. The shape changes and continues to expand. On Earth, this level change is usually associated with volcanic activity, from volcanic eruptions or the movement of magma beneath the vent, which can cause the vent wall to collapse and the vent to expand. The research was published in the latest “Science” journal on March 15.
▲ Changes in the surface of Venus. The image on the right reveals an area of new lava flow near the Maat crater. (Source: NASA)
From 1990 to 1992, Magellan used synthetic aperture radar (SAR) to scan the surface of Venus. With the rotation of Venus, it can scan almost the entire surface of Venus, and the best image resolution reaches 100 meters. About 42% of the entire surface area of Venus was scanned two or more times, making it possible for scientists to further compare surface changes over time. The photos show that the volcanic channel has changed shape and increased significantly in size in less than a year. Geologically changing are the vast highland regions near the equator of Venus, including the two largest volcanoes, Ozza and Maat. The area was long thought to be volcanically active, but until now there was no direct evidence of activity.
▲ The topographic map of Maat Volcano based on the Magellan radar data. (Source: NASA)
While examining Magellan radar images, Herrick identified a crater associated with Maat Volcano that changed significantly between February and October 1991. The crater, which was clearly visible in the February image, doubled in size and changed shape in the August image, and even features a lava lake, clearly showing that the volcano is active. However, due to the different angles and poor resolution of the two shots, the research team built several computer models of volcanic channels with different structures to verify different geological event scenarios. It was concluded from these models that only volcanic eruptions could cause changes. While this is just one data point for the entire planet, it confirms that Venus is still geologically active today.
▲ An image of the VERITAS project. (Source: NASA)
It is amazing that new discoveries can be made from these 30-year-old materials. In fact, in the past ten years, the scientific community has finally obtained the Magellan radar data in a full-resolution and easy-to-analyze manner. This study finally confirms the changing characteristics of lava flows that were previously thought to be difficult to find. The astronomy community is now even more looking forward to the upcoming VERITAS mission, which will be NASA’s first spacecraft to re-explore Venus since the 1990s. It is expected to uncover the mysteries of this planet, which is the closest in size to Earth, but has a completely different fate from Earth.
(This article is reproduced with the authorization of Taipei Planetarium; Source of the first image: NASA)
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