The Grand Canyon in Arizona is a massive natural landmark formed by the Colorado River, which cut through rock over millions of years. However, similar structures can be found not only on Earth, but also on other bodies in the Solar System. For example, there are canyons on the Moon that are the size of Earth’s natural wonder. However, the formation of canyons on the Moon took a very different path, as liquid water is not present there.
Features of canyons on the Moon
Recently, scientists have identified the mechanism for the formation of two lunar canyons, Vallis Schrödinger and Vallis Planck. These structures appeared in just a few minutes as a result of a giant collision, unlike the millions of years of erosion that formed the Grand Canyon on Earth.
Vallis Schrödinger and Vallis Planck are located on the far side of the Moon, near the South Pole. Their dimensions are impressive: Vallis Schrödinger is 270 kilometers long and 2.7 kilometers deep, while Vallis Planck is 280 kilometers long and 3.5 kilometers deep. Although the Grand Canyon on Earth is longer (446 kilometers), it is much shallower at only 1.86 kilometers.
Process of canyon formation
These canyons are part of what are known as ejecta rays, which form in the case of large volumes of material being ejected to the surface during an impact. Researchers led by David Kring of the US Lunar and Planetary Institute have studied their formation process in detail using data from images of the Moon’s surface. They created maps of the directions and distribution of the material that resulted from the impact and reconstructed the impact process itself.
The collision that created the canyons occurred about 3.8 billion years ago, when there were many more large asteroids in the Solar System. The results showed that the impact that formed the Schrödinger crater was asymmetric. Most of the ejected material was distributed away from the Moon’s South Pole. The velocity of the material that was ejected by the impact ranged from 0.95 to 1.28 km/s. The energy from the collision was enormous – about 130 times the entire energy of the world’s arsenal of nuclear weapons.
Importance for future research
NASA’s future Artemis III mission, scheduled for 2027, is to explore areas near the Moon’s South Pole. The exact landing site has not yet been determined, but researchers are confident that the astronauts are in no danger at this location. This study is important for future missions, because the scientists’ models indicate that the ejection material is predominantly concentrated away from the proposed landing sites. This opens up access to ancient minerals from the deep layers of the Moon that the astronauts plan to study.
The study, published in the journal Nature Communications, is another step toward understanding the formation processes of the lunar surface, as well as the history of our moon.
Earlier we reported on how the Moon’s largest craters formed planetesimals.
